Subaru Oil Pump Specs as Relates to Filter Bypass

Posted by: LoneRanger

Subaru Oil Pump Specs as Relates to Filter Bypass - 03/21/09 10:51 AM

It was asked a while back what the numbers were on the Subaru oil pump, during discussion regarding the 23psi bypass pressure setting in the Subaru OE oil filter, as we were trying to figure out why the bypass pressure spec was set so high. So here are the specs on the oil pump, to possibily help understand why the filter bypass rating is set @ 23psi (23.2 actually)

Oil Pump info for 2009 Subaru 2.5 liter four cylinder(identical specs for Turbo DOHC and NA SOHC 2.5 liter motors):


Lubrication Method: Forced lubrication
Pump Type: Trochoid type

Performance (oil temp 80 C which is 176 F)

600rpm: Discharge Pressure 14psi; Discharge rate 4.9 US quarts or more per minute

5000rpm: Discharge pressure 43psi; Discharge rate 49.7 US quarts or more per minute

Relief Valve working pressure: 85psi

Oil Filter

Type: Full Flow
Filtration Area: 124 sq in (800 sq cm)
Bypass Valve opening pressure: 23.2psi
Outer diameter x width: 2.68 x 2.56 in (68 x 65mm)
Installation screw specifications: M 20 x 1.5

Oil Pressure Switch warning light operating pressure: 2.1 psi
Oil Pressure Switch proof pressure: 142 psi


Posted by: Gary Allan

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 03/21/09 12:39 PM

Maybe Superbusa will have a séance with Bernelli for his insight into it.


(yes, I'm waiting )
Posted by: SuperBusa

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 03/21/09 12:59 PM

 Originally Posted By: Gary Allan
Maybe Superbusa will have a séance with Bernelli for his insight into it.


(yes, I'm waiting )


Posted by: Gary Allan

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 03/21/09 01:14 PM

Refresh me, LoneRanger ..does this have a gauge or an idgit light ..and does the turbo get the same pump (which I think comes with a guage)?
Posted by: SuperBusa

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 03/21/09 01:15 PM

 Originally Posted By: LoneRanger

Oil Pump info for 2009 Subaru 2.5 liter four cylinder(identical specs for Turbo DOHC and NA SOHC 2.5 liter motors):


Lubrication Method: Forced lubrication
Pump Type: Trochoid type

Performance (oil temp 80 C which is 176 F)

600rpm: Discharge Pressure 14psi; Discharge rate 4.9 US quarts or more per minute

5000rpm: Discharge pressure 43psi; Discharge rate 49.7 US quarts or more per minute


Relief Valve working pressure: 85psi



Wow ... you got all the detailed specs there.

Looking at the oil pumps output volume - 49.7 qts/min = 12.4 GPM - that's A LOT of oil flow. And that's at 43 psi discharge pressure, which means it can put out that much flow before it's pressure relief valve opens at 85 psi.

IMO, the filter's bypass is set higher because of the high volume oil pump. See chart below - you can see for these typical filters that at 6~8 GPM with COLD oil there is a huge PSID - 45 to 50 psi differential across the element. Of course with hot oil this will come way down.



So, it does look like the Subaru really needs a filer with a high bypass setting in order to ensure less time that the filter is in bypass mode. Obviously, this is more critical when the oil is cold with higher engine RPM. When the oil is near or at full operating temperature I'm sure the 23 psi bypass filter would never or hardly ever be in bypass. But, if you used a filter with a lower bypass there would certainly be more time in bypass mode IMO when the oil was cold and in the warm-up stage ... maybe even possibly when the oil is hot at max engine RPM.

Seems some of the bigger filter manufacture's like WIX or Purolator would come out with a filter with the high bypass setting for these Subarus ... as the filter manufactures are supposed to design their filters based on the vehicle's oil system specs.

No Bernoulli needed just yet.
Posted by: Gary Allan

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 03/21/09 02:49 PM

 Quote:
Looking at the oil pumps output volume - 49.7 qts/min = 12.4 GPM - that's A LOT of oil flow. And that's at 43 psi discharge pressure, which means it can put out that much flow before it's pressure relief valve opens at 85 psi.


hmmm..cold flow and 45lb of differential? That would be only possible if less than half of the output (at whatever output the oil pump was producing) reached the engine @ 85lb. Which cannot occur if the pump is not in relief. We'll, for the moment, assume that the media could withstand 45lb PSID and had no bypass.

Call Bernelli.
Posted by: LoneRanger

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 03/21/09 04:27 PM

 Originally Posted By: Gary Allan
Refresh me, LoneRanger ..does this have a gauge or an idgit light ..and does the turbo get the same pump (which I think comes with a guage)?


Idiot light on mine, mine being the base trim non-turbo. Yes, beginning in model year 2006 both the turbo and non-turbo got the same oil pump with same specs, same filter specs as well.

Before model yr 2006 the specs as posted above were only for the turbo motor, the pressure specs were same for the non-turbo but the volume was a bit less... 3.4 US qts/minute @ 600rpm and 34.4 US qts/minute @ 5000rpm and Relief Valve Pressure was 71psi for the non-turbo motor. Filter bypass at that time was still 23.2psi though.
Posted by: LoneRanger

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 03/21/09 04:34 PM

 Originally Posted By: SuperBusa

Wow ... you got all the detailed specs there.


Yup. From the 2009 Forester factory service manual. :~)
Posted by: SuperBusa

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 03/21/09 11:32 PM

 Originally Posted By: Gary Allan
 Quote:
Looking at the oil pumps output volume - 49.7 qts/min = 12.4 GPM - that's A LOT of oil flow. And that's at 43 psi discharge pressure, which means it can put out that much flow before it's pressure relief valve opens at 85 psi.


hmmm..cold flow and 45lb of differential? That would be only possible if less than half of the output (at whatever output the oil pump was producing) reached the engine @ 85lb. Which cannot occur if the pump is not in relief. We'll, for the moment, assume that the media could withstand 45lb PSID and had no bypass.

Call Bernelli.


Not quite what I meant. This is kind of long and drawn out to get the whole point across ... so hang in there.

Let’s look at those oil pump specs again:

 Quote:
Pump Type: Trochoid type
Performance (oil temp 80 C which is 176 F)
5000rpm: Discharge pressure 43psi; Discharge rate 49.7 US quarts or more per minute
Relief Valve working pressure: 85psi


Imagine that the engine is running at a constant 5000 RPM, and the oil temp is 176 deg F. The oil pump will be putting out 49.7 qts/min (12.4 gpm) at an output pressure of 43 psi. Remember that the engine in this example is always running at 5000 RPM and never changes.

Now imagine that the oil is slowly cooled down … making the oil viscosity correspondingly thicker (higher density). The oil pump will keep putting out 12.4 gpm, but as the oil temp starts to decrease the pump’s output pressure will start to increase in order to keep the 12.4 gpm flowing.

Now imagine that the oil temperature is at yet a some cooler temperature – let’s assume the oil temperature is 100 deg F. The pump output pressure is now 84.9 psi … just at the verge of the pump to start pressure relieving. At this point, the pump is still putting out 12.4 gpm since the pump is still not in relief mode.

So, at this point, if the oil filter develops a PSID greater than its bypass setting, then it will also start to bypass. If the filter's bypass pressure was set to low for this engine, it's entirely possible that it could go into bypass with relatively warm oil since the pump's output is so high volume - much higher than most normal cars IMO.

Now imagine the oil temperature is starting to cool down once again from the 100 deg F point, with the engine still running at 5000 RPM. As the oil becomes cooler and cooler, more and more of the 12.4 gpm output gets spit back into the engine’s sump by the pump's relief vavle, and less flow goes to the filter/engine circuit. But, keep in mind that the viscosity is continually becoming greater as the oil temperature decreases.

Here’s the key … even though the flow rate going through the filter/engine circuit is becoming less and less as the oil cools down, the PSID is also coming down some due to less volume flow, but the PSID is not coming down very fast due to increase in oil viscosity factor … they cancel each other out to some degree.

So … lets assume that when the oil is cold (say 34 deg F) like shown in the chart below, that the oil pump is sending 4 gpm to the filter/engine oil circuit. Also assume that the filter being used has the same flow vs PSID performance curve as the black line (Fram Doubleguard) and has a bypass valve setting of 23 psi for the Subaru.



Well, you can see that in this case, there is a PSID of 23 psi across the filter, so it would be right at the verge of going into bypass mode.

Now assume you put another filter on the Subaru that had a bypass setting of 10 psi. In this case, the filter would have went into bypass at 10 PSID. Looking at the flow graph, this means that ~2.3 gpm will be going through the filter element, and the other 1.7 gpm will be bypassing the filter element to achieve the 4 gpm going to the system.

Obviously Subaru has specified a filter bypass valve setting higher than most engine manufactures because the oil pump is pretty high volume. Any oil pump that puts out 12.4 gpm at 5000 engine RPM at 43 psi discharge pressure also means the oiling system on those engines are not very restrictive, and Subaru wants to feed lots of oil volume to their engines for some reason.

Personally, I would not run any filter that doesn’t have the 23 psi bypass valve on this car … otherwise there could a lot more bypass action while the oil is cold and in the warm-up transition.

Bernoulli not required, and is out riding his Benelli, and unavailable at this time.


Posted by: Gary Allan

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 03/22/09 12:33 AM

 Quote:
Now imagine that the oil is slowly cooled down … making the oil viscosity correspondingly thicker (higher density). The oil pump will keep putting out 12.4 gpm, but as the oil temp starts to decrease the pump’s output pressure will start to increase in order to keep the 12.4 gpm flowing.


Yep. Someone inside the pump said "call down to the boiler room for more steam" ..our 12.4 gpm of throughput is cooling and we have to keep up! Steady as she goes!"


Something is unright about these spec's. The 43psi is not correct. Especially @ 12.4gpm @ 176F.

Ask a turbo owner what the typical pressures are at full op at much lower rpm.


but you've morphed a few things here into non-clarity

 Quote:
Remember that the engine in this example is always running at 5000 RPM and never changes.
 Quote:
let’s assume the oil temperature is 100 deg F. The pump output pressure is now 84.9 psi … just at the verge of the pump to start pressure relieving. At this point, the pump is still putting out 12.4 gpm since the pump is still not in relief mode.


Actually, if stuff was in some rational proportion, this would work out to about 70lb by there figures. It may not really work out that way ..but for "what if" ..we'll go with what you've got there. Still that number is not right.

 Quote:
But, keep in mind that the viscosity is continually becoming greater as the oil temperature decreases.


So ..we can say that our pump called down to the engine room for more steam ..they said "no way, man. We're at our limits! You'll have to vent to atmosphere or we're gonna blow!"

 Quote:
Here’s the key … even though the flow rate going through the filter/engine circuit is becoming less and less as the oil cools down, the PSID is also coming down some due to less volume flow, but the PSID is not coming down very fast due to increase in oil viscosity factor … they cancel each other out to some degree.


Here's the flaw and the key. The pressure seen by the media is (for the moment, it can be exceeded) is 85psi. The engine, seeing that same reduced flow over its restriction, is dissipating less pressure to move whatever volume is being passed through it. THAT produces your differential. The mismatch in that output produced and output realized.

Now in your scenario you've kept the volume extremely high to kick in the absolute impedance of the filter. Still the numbers can't be right. That peak pressure at 12.4 @ 176F is not correct.
Posted by: SuperBusa

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 03/22/09 12:54 AM

 Originally Posted By: Gary Allan
Something is unright about these spec's. The 43psi is not correct. Especially @ 12.4gpm @ 176F.

Ask a turbo owner what the typical pressures are at full op at much lower rpm.


Those are the quoted specs from the Subaru shop manual. I'm assuming they are accurate at this point. One turbo does not define all turbos or other oil system designs. Spec are specs.


 Originally Posted By: Gary Allan
but you've morphed a few things here into non-clarity

 Quote:
Remember that the engine in this example is always running at 5000 RPM and never changes.
 Quote:
let’s assume the oil temperature is 100 deg F. The pump output pressure is now 84.9 psi … just at the verge of the pump to start pressure relieving. At this point, the pump is still putting out 12.4 gpm since the pump is still not in relief mode.


Actually, if stuff was in some rational proportion, this would work out to about 70lb by there figures. It may not really work out that way ..but for "what if" ..we'll go with what you've got there. Still that number is not right.


Keep in mind I'm not trying to predict exact numbers here ... I'm using numbers to show by example what's going on in the system as parameters change.


 Originally Posted By: Gary Allan
 Quote:
Here’s the key … even though the flow rate going through the filter/engine circuit is becoming less and less as the oil cools down, the PSID is also coming down some due to less volume flow, but the PSID is not coming down very fast due to increase in oil viscosity factor … they cancel each other out to some degree.


Here's the flaw and the key. The pressure seen by the media is (for the moment, it can be exceeded) is 85psi. The engine, seeing that same reduced flow over its restriction, is dissipating less pressure to move whatever volume is being passed through it. THAT produces your differential. The mismatch in that output produced and output realized.


Yes, the pressure seen by the filter input is 85 psi when the pump is in relief mode. The delta P across the filter is always going to be proportional to the oil flow volume & viscosity going through it ... a relationship like shown in that "Flow vs PSID" graph posted up earlier in this thread.

So, whatever volume and viscosity of oil that the 85 psi pump pressure can push through the fixed resistance circuit (defined by the filter + engine), will determine the exact volume of oil pushed through the circuit. The PSID across the filter will be determined by the flow rate and viscosity of the oil, and if that PSID is greater than the filter's bypass setting, then the filter will bypass. That's basically what I showed in the previous examples.

So, again ... if an engine has an oil pump with a very high volume output to the filter, that filter better be able to take the larger PSID across the element, and also have a bypass valve set accordingly to prevent unwanted bypass events. Simple as that.

Posted by: edhackett

Re: Subaru Oil Pump Specs as Relates to Filter Byp - 03/22/09 01:10 AM

LoneRanger, does the manual give the part number for the oil filter? The specifications say 124 sq. in. of filter area. I just measured the FRAM and came up with 65 sq. in. (depth of pleat x 2 x number of pleats x width of filter media).

The oversize filter such as the Wix 15356 that you are using and the Purolator PL14610 have ~130 sq. in. of media. The old AA080 Subaru filter (PL14460 size) was probably ~124 sq.in. of media.

This begs the question, would doubling the filter area balance the by-pass events? Would 65 sq. in. at 23 psi vs 130 sq. in. at 12 psi be the same?

Ed
Posted by: Gary Allan

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 03/22/09 01:13 AM

 Quote:
The PSID across the filter will be determined by the flow rate and viscosity of the oil, and if that PSID is greater than the filter's bypass setting, then the filter will bypass. That's basically what I showed in the previous examples.


No it won't. Now in this example, the scenario is manipulated to make it so. You're actually challenging the throughput limits of the filter. Outside of that constructed scenario, it's not so.

Outside of this impedance (effectively a reactive component that takes over beyond a given volume that will have some visc/volume sliding convertibility) the filter doesn't appear this way.

 Quote:
Those are the quoted specs from the Subaru shop manual. I'm assuming they are accurate at this point. One turbo does not define all turbos or other oil system designs. Spec are specs.

For the time being, you've got the shield of documented impunity ..but I'd say that you really are stretching your imagination on the plausibility of this being so.


I haven't quite picked apart everything here ..but you're still left with all the pressures adding up to supply. In one of your manipulations, it appears that you put the filter at parity with the engine with 1/2 of all pressure produced/dissipated over/by the filter.
Posted by: LoneRanger

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 03/22/09 09:33 AM

Subaru offers a Technical Information System web site, http://techinfo.subaru.com/html/index.jsp where you can buy a subscription in varying durations and during the duration you have access to the Service Manual as PDF files, TSB's as PDF files, Tech Tips monthly bulletins, Campaigns (recalls) as PDF's, etc. Model years from 1990 - 2009.

I bought a 72 hr subscription for $34.95 and am in the process of downloading the entire service manual. But they have every little system as a separate PDF for instance the Oil Pump Specs, which means there are a ton of PDF's to download to get the entire Service Manaul-- they limit you to 50 file downloads per hour, when you hit #51 you get a notification that you have to wait x number of minutes before you can download more. I've got about 3/4 of the manual so far, I have Body Section, Wiring System Section, and Body Repair Manual left to get.

It is tedious and time consuming but a factory service manual I can burn to CD for $34.95 I guess it is worth the time consuming effort, lol.

That is where the oil pump specs came from, straight out of the Engine Section- Lubrication section. It does not tell a p/n for the filter on the oil pump spec sheet, just dimensions and specs of the filter.
Posted by: SuperBusa

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 03/22/09 02:43 PM

 Originally Posted By: Gary Allan
 Quote:
The PSID across the filter will be determined by the flow rate and viscosity of the oil, and if that PSID is greater than the filter's bypass setting, then the filter will bypass. That's basically what I showed in the previous examples.


No it won't. Now in this example, the scenario is manipulated to make it so. You're actually challenging the throughput limits of the filter. Outside of that constructed scenario, it's not so.

Outside of this impedance (effectively a reactive component that takes over beyond a given volume that will have some visc/volume sliding convertibility) the filter doesn't appear this way.


Sure it will. What do you think causes the actual pressure drop across an oil filter? ... or any other fluid flow restriction? Flow through an oil filter causes a pressure drop across it. The volume and viscosity of the flow through any filter will develop a pressure drop proportional to the actual flow resistance characteristics of the filter assembly. This includes the filter element, as well as the base inlet holes and the center core outlet holes. They all play a part in the resistance of the filer assembly.

Why do you think manufacture's put a bypass valve in the filers? ... because they KNOW that at some point there will be a large enough PSID across the element to warrant bypassing the flow to keep the PSID to a maximum level. If a filter didn't have any possibility of producing a high PSID then they wouldn't need a bypass valve.

Why do you think Subaru has such a high filter bypass setting? IMO, it's because the oil pump on that engine has a very high volume output compared to many other cars on the road 12.4 gpm is ALOT of volume. They know that with more flow going through the filter that there will be a higher PSID across the filter, and have set the bypass higher to account for this. This gives more bypass "reserve headroom" for filter loading during its use period. If they put the bypass setting lower, then it may not take much filter loading to get its flow resistance higher, and will certainly cut the headroom down for those cold oil flow scenarios.

 Originally Posted By: Gary Allan
 Quote:
Those are the quoted specs from the Subaru shop manual. I'm assuming they are accurate at this point. One turbo does not define all turbos or other oil system designs. Spec are specs.

For the time being, you've got the shield of documented impunity ..but I'd say that you really are stretching your imagination on the plausibility of this being so.

I haven't quite picked apart everything here ..but you're still left with all the pressures adding up to supply. In one of your manipulations, it appears that you put the filter at parity with the engine with 1/2 of all pressure produced/dissipated over/by the filter.


I believe those specs from Subaru. I highly doubt they have an error in them. Until proven otherwise (like a TSB or similar from Subaru) saying there was an error in the shop manual, then those are the specs, and considered accurate.

Yes, I agree that the supply pressure must add up to the total amount of pressure lost through the system as it flows from inlet to outlet (outlet is zero psi - ATM pressure of the sump). BUT, keep in mind that an oiling system that is designed to flow 12.4 gpm of 176 deg F oil at 43 psi is a pretty wide open oiling system. This thing flows like mad ... and hence, the pressure drop across the engine circuit also has to be MUCH LOWER than your everyday vehicle with low volume pumps that only flow probably 1/3 or 1/4 of this Subaru system.

You need to look at what the Subaru system IS, instead of trying to think it must by like all the other systems out there. It's apples to oranges ... why else would Subaru have a bypass setting that is essentially DOUBLE the average bypass setting on 99+% of all other vehicles.
Posted by: SuperBusa

Re: Subaru Oil Pump Specs as Relates to Filter Byp - 03/22/09 02:58 PM

 Originally Posted By: edhackett
LoneRanger, does the manual give the part number for the oil filter? The specifications say 124 sq. in. of filter area. I just measured the FRAM and came up with 65 sq. in. (depth of pleat x 2 x number of pleats x width of filter media).

The oversize filter such as the Wix 15356 that you are using and the Purolator PL14610 have ~130 sq. in. of media. The old AA080 Subaru filter (PL14460 size) was probably ~124 sq.in. of media.

This begs the question, would doubling the filter area balance the by-pass events? Would 65 sq. in. at 23 psi vs 130 sq. in. at 12 psi be the same?

Ed


Yes, there is definitely a relationship between the amount of filtering area to the flow restriction. Obviously, with the same filtering material used, as the flow area goes up the PSID across it will decrease with the same flow volume going through it.

Yes, it's possible that if a filter is larger and less restrictive, then the bypass setting could be set lower. For instance, imaging forcing 12 gpm through a filter the size of a thimble compared to forcing 12 gpm through a filter the size of a 55 gallon drum. Obviously, the thimble sized filer would need a very high bypass setting to ensure the oil actually went through the filter element. It all depends on the expected worse case PSID across the filter, and the expected loading factor, that will determine what the bypass setting should be set to.

If a filter manufactures does their job right, then they would know the exact flow characteristics of a specific engine and design filters accordingly.

LoneRanger - are there any filter manufactures (such as WIX, K&N, M1, etc) that actually have a filter specified for your Subaru? If so, then I would certainly think that they know it has a high volume oiling system and have designed the filter accordingly. If they made a filter, it certainly wouldn't hurt to contact their Engineering Tech Dept to get their inputs to your concern.
Posted by: Gary Allan

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 03/22/09 03:54 PM

 Quote:
The volume and viscosity of the flow through any filter will develop a pressure drop proportional to the actual flow resistance characteristics of the filter assembly.


Take a 2gpm flow through an 8" conduit. Expand the conduit to 12" ..reduce the conduit to 8" ...give it a 2" outlet. How much resistance does the 12" diameter section add in pressure alteration. It decelerates the flow.

Take a 12" conduit ..narrow it to 8" ...expand it to 12" ..give it a 2" outlet. How much does the 8" section add to the pressure alteration? It accelerates the flow.

In both scenarios ..intermediate velocity changes. The mean velocity does not. Since the 2" outlet is by far the most restrictive element ..the intermediate alteration in velocity and therefore pressure, is inconsequential.

 Quote:
Why do you think manufacture's put a bypass valve in the filers? ... because they KNOW that at some point there will be a large enough PSID across the element to warrant bypassing the flow to keep the PSID to a maximum level. If a filter didn't have any possibility of producing a high PSID then they wouldn't need a bypass valve.


The bypass valve and the oil pump relief valve work in concert. They allow slack in an otherwise solid fluid transmission.

Don't tell me that you're still clinging to the absolute resistance of the filter as being the primary reason that a bypass valve operates? Please say that this is not so. It may take me going through the whole deal and actually videoing the event to prove it to you. I'll pull the remote dual oil mount out of mothballs ..hook it up on my jeep and show you the PSID when the relief event occurs. I'll show you it erode when the relief event is over.

Let's say that you have a massive filter. Suppose you've got 60 weight oil @ 32F and you attempt to move that static oil column from ZERO to 1gpm instantaneously. What do you think occurs? The oil pump spins its tires and moves next to no oil. You then have max pressure applied ..but virtually no flow. That's why it takes longer for your system to see pressure. This is where you've got the maximum differential across the filter. Max pressure and minimal flow. The media just gives you a place to read it. At that point, filter or no filter, the flow will be minimal and the pressure peaked.

Is that too hard to see? Are you unable to envision this scenario and concede to it?

 Quote:
Why do you think Subaru has such a high filter bypass setting? IMO, it's because the oil pump on that engine has a very high volume output compared to many other cars on the road 12.4 gpm is ALOT of volume.


If you care to read back on other discussions on filters with higher bypass settings (including with YOU) you'll see that I don't argue with the reason ..and this is even before you attempted to turn Bernelli over.

12.4 is an incredible volume. My HV pump could maybe match it. It's rated @ 9gpm @ 3500 rpm. Since my engine can only process about 5gpm at the same rate I have to use a 20 weight to "fit" the flow through the engine without being in relief. I have to use a 20 weight to have only fractional PSID across my media.


The more I think about it ..the more I can see the above spec's working. As I said this is a prime opportunity for you to continue down this road of non-semantic misinformation in this EXCEPTIONAL situation. It provided an environment that actually needed the 9-11 gpm limits of the filter. The vast galactic universal known dimensions do not dwell here.

 Quote:
This gives more bypass "reserve headroom" for filter loading during its use period. If they put the bypass setting lower, then it may not take much filter loading to get its flow resistance higher, and will certainly cut the headroom down for those cold oil flow scenarios.


No. It allows more filtering in anticipated relief events. Keep in mind that 175F is a good bit off of cold start.

Now it will also allow higher volume at elevated PSID without bypass ..but that won't alter the basic concept of why the two are there. The same loading should occur on 8psi bypass valve filters ...are you saying that the entire rolling population is getting screwed by not using 20psi bypass valves??? It is only at that peak volume where this would be a factor and would not apply to the same size filter at a much more typical flow rate.

 Quote:
If they put the bypass setting lower, then it may not take much filter loading to get its flow resistance higher, and will certainly cut the headroom down for those cold oil flow scenarios.


No. It will elongate the elevated PSID event beyond the cessation of the relief event. It's still not substantial. That is, the effect of volume through an effectively smaller filter will be more pronounced until the fluid warms. You're pushing a heavier fluid through a smaller passage.

 Quote:
I believe those specs from Subaru. I highly doubt they have an error in them. Until proven otherwise (like a TSB or similar from Subaru) saying there was an error in the shop manual, then those are the specs, and considered accurate.



I won't doubt them either. What you've not seen is what occurs at startup. All the spec's are at normalized temps (near enough). And I'd say that you're correct at peak flow with the numbers you're saying.

Again, all filters have a PSID @ XX gpm w/Y visc fluid passing through them. This doesn't mean squat when the choke the filter presents is minimal compared to the engine.

 Quote:
You need to look at what the Subaru system IS, instead of trying to think it must by like all the other systems out there. It's apples to oranges ... why else would Subaru have a bypass setting that is essentially DOUBLE the average bypass setting on 99+% of all other vehicles.


I've conceded to that and experience it myself ..every day. The same applied to VW/AUDI/Porsche/etc. ..except that they have ultra high pressure limits and spec relatively high visc oils. The have 30+ bypass valve settings. It's because they're in relief for up to a half hour. It takes that long to have the gauge come off of 135+ at any normal road speed.


I wish he had a gauge.
Posted by: SuperBusa

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 03/22/09 04:02 PM

Gary ... I'm I going to have to go find Bernoulli again? - you're misinterpreting some of the physics here - or at a minimum my description of the physics. Maybe when I have the time I'll respond to some of your stuff.
Posted by: Gary Allan

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 03/22/09 04:16 PM

I guess you will make me go through all the hardware rigging. I had a great platform to do this lame stuff on with my minivan ..but it goes stolen ..with a good bit of my hardware in it.

..but if you insist.. I will show you low volume with high differential at cold temps ..and I will show you high volume at cold temps with virtually no differential. I will also show you high volume with virtually no differential.

You'll have one out for weasel room. I won't be able to quote volume ..but ..if we're genuinely trying to work on "seeing" ..you'll forgo the opportunity to skate.

How do you think I came up with all this? Just pulled it out of my behind? No, pal. It's REAL
Posted by: LoneRanger

Re: Subaru Oil Pump Specs as Relates to Filter Byp - 03/22/09 04:51 PM

 Originally Posted By: SuperBusa
LoneRanger - are there any filter manufactures (such as WIX, K&N, M1, etc) that actually have a filter specified for your Subaru? If so, then I would certainly think that they know it has a high volume oiling system and have designed the filter accordingly. If they made a filter, it certainly wouldn't hurt to contact their Engineering Tech Dept to get their inputs to your concern.


Wix filter for my car is 51365 with bypass rated at 8-11psi, plus it appears to be a universal filter hence the lawn tractors and outboard marine motors it also is purported to fit:

http://www.wixfilters.com/filterlookup/ResultsPart.asp?PartNo=51365

Click the part number for a pop-up with specs and fitment for the filter.

I removed the Wix 51365 this past week after this discussion made me increasingly uncomfortable with the low bypass setting.

I now have one of the OE Subaru filters on again, the Honeywell made blue ones-- local dealer sells them for $6... cheap compared to what other Subaru dealers are charging for them. Filter changes are mess-free and super easy on this car.

Posted by: SuperBusa

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 03/22/09 05:53 PM

 Originally Posted By: Gary Allan
I guess you will make me go through all the hardware rigging. I had a great platform to do this lame stuff on with my minivan ..but it goes stolen ..with a good bit of my hardware in it.

..but if you insist.. I will show you low volume with high differential at cold temps ..and I will show you high volume at cold temps with virtually no differential. I will also show you high volume with virtually no differential.

You'll have one out for weasel room. I won't be able to quote volume ..but ..if we're genuinely trying to work on "seeing" ..you'll forgo the opportunity to skate.

How do you think I came up with all this? Just pulled it out of my behind? No, pal. It's REAL


But your missing the whole point ... it's the VOLUME that's going to make or break this whole discussion. It's the volume in question that makes this situation different than in most cars on the road. Any engine that puts out tons of oil volume is going to have to use a filter that is capable of working correctly in that environment. What kind of filters are used on race cars that put out tons of oil volume? Tell you something.

My whole point here is that the Subaru's oiling system under discussion has uncommonly high volume output for a road car.

If the pump puts out high volume under hot conditions (per the spec), then it will also put out a relatively high volume output under cold oil conditions, as compared to other vehicles. That's because the oiling system is much more unrestrictive than what you are use to seeing and playing with. An unrestrictive system will flow more cold oil than a restrictive one ... and that means the filter used on it will also have to handle a higher cold oil flow volume.

Can you get your head around on just how much 12.4 gpm is? - that's like a wide open garden hose flowing. If the engine only holds say 5 quarts, that means the entire sump volume is exchanged nearly 10 times every minute if the engine was running at 5000 RPM. That's HUGE, and yes somewhat hard to believe - but we have to believe Subaru's specs unless proven false somehow.

If the system on that engine can flow 12.4 gpm with 176 deg F oil, and it only requires 43 psi of supply pressure to do so (much less than the pump's relief pressure setting), then the oiling system can not be a very restrictive compared to some other cars. In fact, it even has some margin in it's performance to flow the full 12.4 gpm with oil colder than 176 deg F, meaning you could increase the oil viscosity to the point until the pump bumps up against its 85 psi relief setting to push the 12.4 gpm through the system.

I think you are under the impression that this oiling system is like 99% of all the others on the road ... forget what you think it should do and look at what it does based on the specs from Subaru.

If you did a test where you could flow 12.4 gpm of oil (at say whatever oil temp keeps the pump just a hair below the 85 psi relief setting), I'm sure you'd see MUCH MORE than a few PSID across the element. That's why Subaru has specified a 23 psi filter bypass setting (at least on their specific OEM filter), so that they ensure the bypass doesn't open when it shouldn't.
Posted by: SuperBusa

Re: Subaru Oil Pump Specs as Relates to Filter Byp - 03/22/09 06:14 PM

 Originally Posted By: LoneRanger

Wix filter for my car is 51365 with bypass rated at 8-11 psi, plus it appears to be a universal filter hence the lawn tractors and outboard marine motors it also is purported to fit:

http://www.wixfilters.com/filterlookup/ResultsPart.asp?PartNo=51365

Click the part number for a pop-up with specs and fitment for the filter.

I removed the Wix 51365 this past week after this discussion made me increasingly uncomfortable with the low bypass setting.

I now have one of the OE Subaru filters on again, the Honeywell made blue ones-- local dealer sells them for $6... cheap compared to what other Subaru dealers are charging for them. Filter changes are mess-free and super easy on this car.



I'm familiar with that filter, it's the same one called out for my V6 Altima engine (VQ35DE). I just bought the longer version for my next oil change (NAPA Gold 1356, which would be the WIX 51356) since I have enough room to run a longer filter. Can you use the longer filter? ... I think I remember you saying you can't due to clearance issues.

After looking at the oil pump specs on your Subaru, I'd also be a little nervous using a non-OEM filter unless I got specific word from the filter manufacture’s Engineering Department that they understand the oil pump on that car is high volume, and the filter has been verified to work correctly. It could be that they don't care much because after the oil warms up the filter would probably work just fine and they figure that some cold oil bypass is acceptable without any major ill effects. Hard to say exactly what's in the minds of these filter designers sometime.

If you contact WIX or whoever, I'd be interested in hearing their inputs on this one.
Posted by: LoneRanger

Re: Subaru Oil Pump Specs as Relates to Filter Byp - 03/22/09 06:46 PM

If anyones wants to see where I drew these specs from PM me an email addr and I can email the PDF file that has this info in it.
Posted by: LoneRanger

Re: Subaru Oil Pump Specs as Relates to Filter Byp - 03/22/09 06:57 PM

To add another dimension to the OE filter vs Wix 51365 comparison as has surfaced in this discussion, here is a picture of a new unused Wix 51365's filter element compared to a used Subaru blue OEM (Honeywell) filter element after both cans were cut open (w/a hack saw-- kind of sloppy but it worked... chewed up the Honeywell's end cap a bit):



As can be seen, the OE filter appears to feature more media. which only seems to hurt the case against using the Wix in this car even more as smaller media area = higher PSID but with a bypass setting almost 1/3 the strength of the OE spec.
Posted by: rcy

Re: Subaru Oil Pump Specs as Relates to Filter Byp - 03/22/09 07:25 PM

 Originally Posted By: LoneRanger
 Originally Posted By: SuperBusa
LoneRanger - are there any filter manufactures (such as WIX, K&N, M1, etc) that actually have a filter specified for your Subaru? If so, then I would certainly think that they know it has a high volume oiling system and have designed the filter accordingly. If they made a filter, it certainly wouldn't hurt to contact their Engineering Tech Dept to get their inputs to your concern.


Wix filter for my car is 51365 with bypass rated at 8-11psi, plus it appears to be a universal filter hence the lawn tractors and outboard marine motors it also is purported to fit:

http://www.wixfilters.com/filterlookup/ResultsPart.asp?PartNo=51365

Click the part number for a pop-up with specs and fitment for the filter.

I removed the Wix 51365 this past week after this discussion made me increasingly uncomfortable with the low bypass setting.

I now have one of the OE Subaru filters on again, the Honeywell made blue ones-- local dealer sells them for $6... cheap compared to what other Subaru dealers are charging for them. Filter changes are mess-free and super easy on this car.



I did the same thing on my 2001 H6 which also needs a filter with the 23psi bypass(when I'm at my desktop, I'll post the specs for the oil pump/filter for that car - I have the service manual pdf on that computer). The car has a 6 litre oil capacity.

I had been using a Wix filter on my car as well, but switched back to the Canadian Subaru filter (when you say Honeywell, you really mean FRAM right - you just can't bring yourself to type that four letter word haha).

Speaking of filters for Subaru's - I replaced the tranny filter (which is a spin-on) with a Wix as well. I see the bypass on the Wix tranny filter is also 8-11psi. I wonder if I should switch this filter back to Subaru? One big difference is that on the Subaru tranny filter, there is a fine metal mesh screen AFTER the bypass filter. I assume this is to catch any larger debris that might blow out when the filter goes into bypass mode. I would hazard a guess that this filter is also a FRAM.
Posted by: Gary Allan

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 03/22/09 07:36 PM

 Quote:
it's the VOLUME that's going to make or break this whole discussion.


Naturally. It's the only thing to leave out

 Quote:
It's the volume in question that makes this situation different than in most cars on the road.


Yes. So do you now concede to things that you've been avoiding like the plague?

Let's "qualify" your statements. It's ONLY in this or like situations that a filter has any merit in terms of resistance or restriction, correct??


the rest was a waste of typing. Captain Obvious to my rescue.


Except maybe this:

 Quote:
That's why Subaru has specified a 23 psi filter bypass setting (at least on their specific OEM filter), so that they ensure the bypass doesn't open when it shouldn't.



Cold start relief events: MANY

5000rpm 12.4gpm events: FEW

Likely duration of dwell time in bypass

Cold start relief events: MANY

5000 rpm 12.4 gpm events: FEW

Likely sensible benefit to a high bypass valve setting????
Posted by: rcy

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 03/22/09 07:57 PM

Here are the specs for a 2001 H6. Even back then a 23psi bypass was spec'd

[img][/img]
Posted by: SuperBusa

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 03/22/09 08:46 PM

 Originally Posted By: Gary Allan
 Quote:
it's the VOLUME that's going to make or break this whole discussion.


Naturally. It's the only thing to leave out

 Quote:
It's the volume in question that makes this situation different than in most cars on the road.


Yes. So do you now concede to things that you've been avoiding like the plague?


I've said that from the first few posts in this thread. It's not a matter of me "condeding", but more of a matter of your reading comprehension.

 Originally Posted By: Gary Allan
Let's "qualify" your statements. It's ONLY in this or like situations that a filter has any merit in terms of resistance or restriction, correct??


the rest was a waste of typing. Captain Obvious to my rescue.


Huh ... agian, you're just realizing this? Where have you been? Please, go back and read this thread about 3 times ... it might sink in then. I've qualified my disussion in this thread in every manner possible. Let me say it one more time ... it's all a matter of flow VOLUME in this case. More flow VOLUME means more filter PSID, which means the filter bypass needs to be set higher accordingly for all possible use senarios ... including cold starts and running the engine during oil warm up period.


 Originally Posted By: Gary Allan
Except maybe this:

 Quote:
That's why Subaru has specified a 23 psi filter bypass setting (at least on their specific OEM filter), so that they ensure the bypass doesn't open when it shouldn't.



Cold start relief events: MANY

5000rpm 12.4gpm events: FEW

Likely duration of dwell time in bypass

Cold start relief events: MANY

5000 rpm 12.4 gpm events: FEW

Likely sensible benefit to a high bypass valve setting????



Actually, it would NOT flow 12.4 gpm when the oil is cold ... I thought we already established this point. Every thing you've parroted has already been painstakingly explained (for your benefit – or was it to give you a reason to counter argue every point) in my previous posts.

The fact still remains that Subaru has set the filter bypass to 23 psi for a specific reason ... not just to be different from everyone else. The reason is because of the high volume oil pump and the free flowing oil system on this engine. I've explained it every which way I can ... anything else is a waste of time.

So, it sounds like your suggestion is to put whatever oil filter on this car and not worry about it? … that seems kind of careless to me.

If it was my car, I’d run the OEM filter. I’d contact the Engineering Dept of anyone who actually lists a filter for this specific car and ask them to prove to me that they have accounted for the high oil pump volume on this application. Otherwise, I’d be leery of just throwing any oil filter on it.

Either that, or just don't rev the engine much until the oil is pretty hot ... but who want's to screw with that all the time?
Posted by: SuperBusa

Re: Subaru Oil Pump Specs as Relates to Filter Byp - 03/22/09 09:01 PM

 Originally Posted By: LoneRanger
To add another dimension to the OE filter vs Wix 51365 comparison as has surfaced in this discussion, here is a picture of a new unused Wix 51365's filter element compared to a used Subaru blue OEM (Honeywell) filter element after both cans were cut open (w/a hack saw-- kind of sloppy but it worked... chewed up the Honeywell's end cap a bit):



As can be seen, the OE filter appears to feature more media. which only seems to hurt the case against using the Wix in this car even more as smaller media area = higher PSID but with a bypass setting almost 1/3 the strength of the OE spec.


I've seen filters on 600cc motorcycles bigger than that! There might be a slight illusion here though ... I'd bet the metal end caps only cut some of the effective filer area; less than what it appears like.

So I take it you can't use the 51356 which has the same filter specs, but about 1" longer? Of course the bypass is still 8-11 psi on that one, so I'd still be leary until further info could be obtained from WIX.
Posted by: Gary Allan

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 03/23/09 03:27 AM

 Quote:
So, it sounds like your suggestion is to put whatever oil filter on this car and not worry about it? … that seems kind of careless to me.


I dunno. Maybe "I" wouldn't worry about it. Then again, I use 0w-10 oil, so what do I know

You're just getting fall out from our last slug fest, that's all. In evaporators, it's called "carry over".

 Quote:
Actually, it would NOT flow 12.4 gpm when the oil is cold


Let's read this again ...for clarity ...

Cold start relief events: MANY

5000rpm 12.4gpm events: FEW

Likely duration of dwell time in bypass

Cold start relief events: MANY


I don't see any reference to 12.4gpm of cold flowing oil, just cold start events. Do you really see it (imagine a piece of paper that I flip over and examine both sides ..several times ..and blink as though to clear my eyes)
Posted by: Thingfish

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 03/23/09 08:41 AM

FWIW, I fit the 51344 in my '03 wrx. With a 0/20 BTW..
Posted by: SuperBusa

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 03/23/09 12:54 PM

 Originally Posted By: Gary Allan
 Quote:
So, it sounds like your suggestion is to put whatever oil filter on this car and not worry about it? … that seems kind of careless to me.


I dunno. Maybe "I" wouldn't worry about it. Then again, I use 0w-10 oil, so what do I know

You're just getting fall out from our last slug fest, that's all. In evaporators, it's called "carry over".

 Quote:
Actually, it would NOT flow 12.4 gpm when the oil is cold


Let's read this again ...for clarity ...

Cold start relief events: MANY

5000rpm 12.4gpm events: FEW

Likely duration of dwell time in bypass

Cold start relief events: MANY


I don't see any reference to 12.4gpm of cold flowing oil, just cold start events. Do you really see it (imagine a piece of paper that I flip over and examine both sides ..several times ..and blink as though to clear my eyes)


I don't see any statement saying the oil is hot either. And why would you worry about 12.4 gpm at 5000 RPM with hot oil anyway? ... didn't we conclude (more than once) that is an operating condition that is not as critical as cold starts and high engine RPM during oil warm-up phase? Don't weasel out here ... are you studying to become a kangaroo court lawyer in your spare time?
Posted by: Gary Allan

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 03/23/09 03:23 PM

 Quote:
I don't see any statement saying the oil is hot either.


Well, we've probably both figured out that you probably couldn't push 12.4 gpm of cold oil through the engine ..you would be in a relief event (most likely) ...and that's where we're nearer the "cold start" scenario.

 Quote:
didn't we conclude (more than once) that is an operating condition that is not as critical as cold starts and high engine RPM during oil warm-up phase?


I didn't see any conclusion on your part (I may have lost it in the salvos). I've seen you repeatedly cite the hot oil 12.5 gpm scenario to bolster your pressure/restriction POV ..and, in implication, attempt to apply it over the full span of operation. ..or did I get that wrong?

 Quote:
are you studying to become a kangaroo court lawyer in your spare time?


Debate is an art, my friend. I do thank you for challenging me at my limits. The art of winning any debate is conceding to the obvious and passing over it and moving on to promote your POV with reasons that show its advantages/strengths. You'll note my repeated (and ignored) references to "granted and conceded to". You went on to treat me as a plebe on primary fundamentals of differentials and pressures, bogging the discussion down in needlessly redundant information ..while never attacking my basic way of viewing the events as they occur. "Let's get beyond this and see if you can manage this" fell on deaf ears.

I was sitting there with my partner and we had a problem with the evaporator and he couldn't understand it. I blurted out as close a parallel scenario in another system as I could in an attempt to get him to relate to what was going on. He gave me some static about the lack of contour to what was at hand. I then said, "For a minute ..pretend that you actually want to understand what I'm saying and not engage in an argument". He paused ..and nodded his head in understanding. He had to choose to employ the abstract thought process. It wasn't a natural act for him. For me, it's FIRST nature.

This is how I've rationalized these physical events. If you're going to install a new paradigm for me, you're going to have to work from within my understanding and make it not work. For that, you'll first have to attempt to see how I've got where I am and then prove that pathway to be in error. I can't think too much outside of the box that I've constructed. I don't have the disciplined back ground to do so.
Posted by: SuperBusa

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 03/23/09 05:46 PM

 Originally Posted By: Gary Allan

 Quote:
didn't we conclude (more than once) that is an operating condition that is not as critical as cold starts and high engine RPM during oil warm-up phase?


I didn't see any conclusion on your part (I may have lost it in the salvos). I've seen you repeatedly cite the hot oil 12.5 gpm scenario to bolster your pressure/restriction POV ..and, in implication, attempt to apply it over the full span of operation. ..or did I get that wrong?


The conclusion is buried in here somewhere – you just skim over some of this stuff I’m willing to bet. The “bolstered” examples were to show just how much flow volume the filter would have to take on in a max flow case ... which is obviously hot oil without any pump relief - or even just warm oil since the pump isn’t near the 85 psi relief at quoted flow spec. Since the 12.4 gpm flow spec was quoted at 43 psi, and the pump relieves at 85 psi, then all 12.4 gpm will go through the filter. IMO, that is one reason the filter’s bypass is set to 23 psi ... because 12.4 gpm, even with warm oil, is a HUGE flow rate compared to some engines and can create a pretty significant PSID. Of course, there could be a worse case than that if whatever flow rate (in gpm) you can get through the filter with cold oil with 85 psi pushing it through the system. The higher viscosity at a much reduced flow rate would probably cause the highest PSID case. Of course, without doing some heavy duty number crunching, or and actual flow test one would not know for sure.

What do you think a typical say LSx GM V8 engine flows at near redline? I guess I could get my factory service manual out and see ... but I’d be very surprised if it is near 12.4 gpm at max flow conditions. Of course, most GM V8s use a somewhat larger filter than the Subaru in this discussion, so that alone helps the designed bypass PSI setting come down some.

 Originally Posted By: Gary Allan
Debate is an art, my friend. I do thank you for challenging me at my limits. The art of winning any debate is conceding to the obvious and passing over it and moving on to promote your POV with reasons that show its advantages/strengths.


Humm ... seems more than not you will challenge the obvious described by me, just to put it in your own words – or many you don’t quite grasp the concept because it’s not described in a manner you expect (?). This is what makes these round ‘n round discussions (on both our parts) at times one big cluster [you know what]. ;\)
Posted by: Gary Allan

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 03/23/09 06:19 PM

 Quote:
What do you think a typical say LSx GM V8 engine flows at near redline? I guess I could get my factory service manual out and see ... but I’d be very surprised if it is near 12.4 gpm at max flow conditions. Of course, most GM V8s use a somewhat larger filter than the Subaru in this discussion, so that alone helps the designed bypass PSI setting come down some.


It's probably quite high. I don't know if it would be in the 12gpm realm ..but I wouldn't be surprised with 10+/-.

We keep defaulting to the ultra ubber here.

You're new, so you haven't heard ..literally thousands of times... "I've purchased XYZ filter because it flows better" when flow is not a function of the filter. It's a function of the pump.

It's the difference of two people viewing "I chose 10w-40 so it would be thicker when hot and thinner when cold". While I'm giving orientation on the fact that the cold spec is VERY THICK (which would not be apparent in the static statement without qualification) ..you're up there on the 40 weight properties.

 Quote:
Humm ... seems more than not you will challenge the obvious described by me, just to put it in your own words – or many you don’t quite grasp the concept because it’s not described in a manner you expect (?).


I see said the reflection in the mirror.
Posted by: WagonBoss

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 03/23/09 07:24 PM

After lurking around this site for several years and recently registering I'm compelled to make my first post. I have 2 Subies to maintain and found this a very interesting discussion, though much was far over my head.

I wrote to customer service at Hastings and this is the reply, though not technically helpful I found it to be an honest statement FWIW.

Recently there has been a bit of discussion on Subaru lube filters and the Subaru oil system on enthusiasts forums. The gist is that Subaru recently announced a new filter which the user community believes is produced by Honeywell (Fram) to Subaru specifications. Frankly, there is not much happiness in this new product. The discussion on the oil system indicates that Subaru uses a high volume oil pump and specifies a 23 PSID pressure relief valve.
I have two Subaru cars with the 4 cylinder 2.5 liter non-turbo engine. Both use a LF113 (or the longer LF240). My search through the various filter manufacturers' sites (Hastings/Baldwin, Wix, Fram, and Purolator) reveals that no filters, searched for my application, contains the 23 PSID pressure relief valve as specified. My primary concern is cold flow on startup as these are daily drivers - not a performance application. I use 5w-30 oil as recommended by the owners manual.
Should I be concerned about the difference between the 14 PSID spec on the LF113 and the factory spec of 23 PSID? Is there any technical reason the correct pressure relief is not available? Are there any plans to offer a filter with the correct specification?

Thanks in advance for your help. It is quite bewildering to have this great a variance in specifications.


REPLY:
Thank you for using Hastings Filters. I do not recommend using a filter with a 14-16 psi bypass valve in an application which calls for a filter with a 23 psi by-pass valve. We design our filters with a 3 psi maximum tolerance with regards to bypass valves. Therefore, I doubt that we would cross the new Subaru number to either the LF113 or the LF240. We do have a very similar filter with a 20 psi bypass valve. This is the LF491. If you have further questions, please feel free to contact me.
Cordially,

TRAVIS R. WINBERG
SUPERVISOR OF SERVICE ENGINEERING
Posted by: SuperBusa

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 03/23/09 07:41 PM

 Originally Posted By: Gary Allan
 Quote:
What do you think a typical say LSx GM V8 engine flows at near redline? I guess I could get my factory service manual out and see ... but I’d be very surprised if it is near 12.4 gpm at max flow conditions. Of course, most GM V8s use a somewhat larger filter than the Subaru in this discussion, so that alone helps the designed bypass PSI setting come down some.


It's probably quite high. I don't know if it would be in the 12gpm realm ..but I wouldn't be surprised with 10+/-.


I've got the factory service manual for a 2002 LS1/LS6, so I'll see if it has any oil system specs listed.

 Originally Posted By: Gary Allan
You're new, so you haven't heard ..literally thousands of times... "I've purchased XYZ filter because it flows better" when flow is not a function of the filter. It's a function of the pump.


That statement is way too general, or just plain wrong. ;\) In actuality, the flow volume THROUGH THE SYSTEM (which includes the filter) is a function of the pump's supply pressure AND the flow circuit resistance. Yeah, the pump's output performance has a bearing on the system flow, but so does the flow circuit's resistance which includes the filter (PSID). IF a filter is indeed was very restrictive, then it WILL effect the flow volume going through the engine - especially if the oil is cold or is very high volume. For some reason you can't seem to grasp this concept - please tell me you're on the same page here. You have to look at the entire SYSTEM to see what's going on. If you have a constant pump supply pressure, then the oil flow will choke down more and more through the circuit as the restriction to flow increases. The ONLY way a filter will NOT affect the oil flow going through an engine is if it has zero flow PSID (impossible) or the bypass is set to zero (doubt it).

Man in the mirror looking ... humm.
Posted by: SuperBusa

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 03/23/09 07:49 PM

WagonBoss - interesting reply from Subaru, and right in line with the discussions here. So glad you joined in, and amazing that it took a wild thread like this one to get you to post.

 Originally Posted By: Subaru Tech Dept
I do not recommend using a filter with a 14-16 psi bypass valve in an application which calls for a filter with a 23 psi by-pass valve. We design our filters with a 3 psi maximum tolerance with regards to bypass valves.


The high volume pump is the reason why Subaru recommends using a filter with the 23 psi bypass setting. They understand that with higher volume of oil going through the filter, that there is a corresponding higher pressure drop across the element and have taken measures to ensure less filter bypass occurances. If they only have a 3 psi max tolerance (ie, "headroom") on the bypass setting, then they expect to see 20 PSID events across the filter element - at least that's how I read it.
Posted by: WagonBoss

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 03/23/09 08:09 PM

Just for clarity the reply was from Hastings Filter - not Subaru. I found it interesting they aren't recommending the filter they say is the correct filter for the application.
Posted by: deeter16317

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 03/23/09 08:44 PM

Couple points...

At almost 50 quarts of oil per minute, would you not expect the pump to literally suck the sump empty?? Sorry, but the oil doesn't return to the sump that fast in the real world as it gets hung up on things...

And do you REALLY think you are using almost 50 quarts per minute?? Think about the clearances...while the pump might be able to flow that much oil, its doubtful the engine (even in a completely worn out scenario) would flow that much oil...

If the clearances actually allowed that much flow, the engine would starve of oil at an idle...
Posted by: LoneRanger

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 03/23/09 09:53 PM

Okay, to clear up any questions as to the oil pump specs I posted here is the service manual excerp:

Posted by: LoneRanger

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 03/23/09 09:59 PM

WagonBoss, good info from Hastings there. I'm now resigned to using the blue OE Subaru filter, though. This discussion has moved me to that conclusion, and that is a good thing in the end, even if I'm not a huge fan of Honeywell (FRAM) filter materials and design it is the factory authorized part and apparently these blue ones are the ones going on Subaru's leaving the assembly plant in Lafayette, Indiana (accross the river from my Alma Mater-- Go Purdue!). Also,in the rare event something comes up with my motor, being under warranty, Subaru can't balk on a claim over anything to do with the oil filter if its an OE (provided I can prove adherance to the maintenance schedule in the manual).
Posted by: Thingfish

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 03/24/09 02:10 AM

With the WIX filter having an 8-11 GPM max flow rate, wouldn't the filter have to be in bypass at high rpms? Even with 0/20 @ 180 oil temp ( Motul 300v 0/20 ) I still see almost 75-80 psi at almost anything above idle. Fwiw, my redline is in excess of 8K rpm on 91 octane, and I deal with cars that exceed 9K rpm on race fuel. It would be frightening to think that everything is going past the media. ( I typically use nothing but oversized WIX and Amsoil filters )

For some reason, I see Subarus flow rates being a typo or mistake ( Wishfull thinking maybe? ). I am looking through my WRX factory manuals, but cannot find the info.

Being a Subaru specialist, I have bumped into mistakes with Subaru info many times in the past.


Looks like I may have to look into a remote filter mount, with a pair of filters in parallel. It would at least give me a chance to use VERY large filters.
Posted by: Thingfish

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 03/24/09 02:22 AM

 Originally Posted By: LoneRanger
WagonBoss, good info from Hastings there. I'm now resigned to using the blue OE Subaru filter, though. This discussion has moved me to that conclusion, and that is a good thing in the end, even if I'm not a huge fan of Honeywell (FRAM) filter materials and design it is the factory authorized part and apparently these blue ones are the ones going on Subaru's leaving the assembly plant in Lafayette, Indiana (accross the river from my Alma Mater-- Go Purdue!). Also,in the rare event something comes up with my motor, being under warranty, Subaru can't balk on a claim over anything to do with the oil filter if its an OE (provided I can prove adherance to the maintenance schedule in the manual).



The Purolator for the Subaru, ( the 14460 ) has a 20-25 psi bypass.
Posted by: Gary Allan

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 03/24/09 03:37 AM

 Quote:
That statement is way too general, or just plain wrong.


Well, it is a general statement. As it stands it is 100% correct. There is no functional way that a filter can produce flow or inhibit flow by itself. It requires some alteration of the pump.

..btw- I'll see if Lone Ranger has a schematic of where the tap is for the pressure reading. If it's downstream of the filter, then the pump will see 60 psi @ the 12.4gpm @ 17xF at whatever visc it's spec'd at. It will elevate the pressure as seen by the pump. I suspect that it is.

 Quote:
In actuality, the flow volume THROUGH THE SYSTEM (which includes the filter) is a function of the pump's supply pressure AND the flow circuit resistance


Well, in actuality ..it's far easier to figure that the pump will have variable pressure, at a given IMMUTABLE VOLUME, through a given restriction.

Here's Bernelli for you, yo!

 Quote:
Yeah, the pump's output performance has a bearing on the system flow, but so does the flow circuit's resistance which includes the filter (PSID). IF a filter is indeed was very restrictive, then it WILL effect the flow volume going through the engine - especially if the oil is cold or is very high volume.


That statement is way too general and just plain wrong. The pump, in the vacuum in the absence of senseless qualification that you seem to insist that I waste time on ..but are too lazy to do yourself, could care less whether it sees cold glue. Our theoretical pump has no boundaries unless they're qualified. Did Bernelli only exist in the mundane of what he could practically do??

For some reason you seem to grasp and lose this concept depending on which post you're typing.

 Quote:
You have to look at the entire SYSTEM to see what's going on.


I'm afraid that you don't. I don't have to know internal pump head or anything that you insist is essential to know/see the effects upon the filter. You seem to be unable to divorce Bernelli from the undeniable physical events and give them powers that aren't essential to understanding what occurs (more often then not).

 Quote:
If you have a constant pump supply pressure, then the oil flow will choke down more and more through the circuit as the restriction to flow increases.


Again, in your unqualified statement, that's just plain wrong. Double the oil gallery and all passages in the engine and run the pump at the same rate ..the same volume will be flowing. The pressure developed will be less (assume for the sake of discussion that the pump is of 100% efficiency and that the pump is operated at some rational flow rate to avoid marginal/exceptional influences - how's that for qualification).

This is one concept that you have 100% inability to grasp. You keep going back to a faucet.

 Quote:
The ONLY way a filter will NOT affect the oil flow going through an engine is if it has zero flow PSID (impossible) or the bypass is set to zero (doubt it).


So, now you're implying that if Subaru eliminated the filter ..that the 12.4gpm figure would be more (under the same qualified conditions that I described)??

NOW we're really getting somewhere here.
Posted by: LoneRanger

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 03/24/09 05:37 AM

 Originally Posted By: Gary Allan

..btw- I'll see if Lone Ranger has a schematic of where the tap is for the pressure reading. If it's downstream of the filter, then the pump will see 60 psi @ the 12.4gpm @ 17xF at whatever visc it's spec'd at. It will elevate the pressure as seen by the pump. I suspect that it is.


I should have a schematic or exploded parts view, as I grabbed all the pages for the engine portion of the manual. Long day today at work coming up, but later this evening I will look and post what I find.
Posted by: Gary Allan

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 03/24/09 08:45 AM

Great! I know you've been hijacked here ..

Now ..back to the slugfest.


At loggerheads: Idiom Definitions for 'At loggerheads'
If people are at loggerheads, they are arguing and can't agree on anything.
Posted by: Paul B.

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 03/24/09 09:53 AM

I've been reading this thread with interest since I drive a 2005 Subaru with the Turbo engine. I think that their is a durability issue related to the high volume/pressure lubrication system and a high incidence of turbocharger failures, and found the response from the oil filter Mfg (Hastings) especially interesting.
In certain models (2005 is one of them) the oil line carrying filtered oil from the right side cylinder head to the Turbo has fine mesh sreen filter located in a banjo fitting at the exit from the head. On some engines this screen has become blocked with debris resulting in broken shaft in the Turbocharger. It's a chore to remove the screen to check/clean it, and it's not called for in any of the factory prescribed maintenance.
Since the their is only filtered oil going in to the line, I have wondered where the deris would come from in amounts large enough to block the screen completely. Now I think I see a cause for it. If aftermarket filters are run with bypass valves designed to open at 11 psi or even less, I can see that they could be running in bypass mode for a long enough time that it could cause the probem.
Some people have checked the screen condition after 60,000 miles and found nothing in it, while others suffer oil starvation turbo failures at 30,000 miles. I haven't seen anybody blame aftermarket filters yet, but I think it's a real possibility.
Posted by: SuperBusa

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 03/24/09 12:14 PM

 Originally Posted By: deeter16317
Couple points...

At almost 50 quarts of oil per minute, would you not expect the pump to literally suck the sump empty?? Sorry, but the oil doesn't return to the sump that fast in the real world as it gets hung up on things...

And do you REALLY think you are using almost 50 quarts per minute?? Think about the clearances...while the pump might be able to flow that much oil, its doubtful the engine (even in a completely worn out scenario) would flow that much oil...

If the clearances actually allowed that much flow, the engine would starve of oil at an idle...



 Originally Posted By: Thingfish
With the WIX filter having an 8-11 GPM max flow rate, wouldn't the filter have to be in bypass at high rpms? Even with 0/20 @ 180 oil temp ( Motul 300v 0/20 ) I still see almost 75-80 psi at almost anything above idle. Fwiw, my redline is in excess of 8K rpm on 91 octane, and I deal with cars that exceed 9K rpm on race fuel. It would be frightening to think that everything is going past the media. ( I typically use nothing but oversized WIX and Amsoil filters )

For some reason, I see Subarus flow rates being a typo or mistake ( Wishfull thinking maybe? ). I am looking through my WRX factory manuals, but cannot find the info.

Being a Subaru specialist, I have bumped into mistakes with Subaru info many times in the past.


I agree that it seems like a HUGE (and unbelievable) amount of oil volume output from the oil pump. It very well could be a typo, but who can prove it? I don’t think my garden hose even flows at 12 gpm.
Posted by: LoneRanger

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 03/24/09 12:21 PM

Welcome to the discuss, Paul B.

Gary: I don't consider the discussion to be a thread hijack at all, it has been informative... well as informative as it can be for me since trying to wrap my brain around some of the concepts you and Superbusa are discussing can be challenging at times as I have no training in fluid dynamics or fluid mechanics.

Now, to find that schematic for the oil pressure sender...
Posted by: SuperBusa

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 03/24/09 12:34 PM

 Originally Posted By: Gary Allan
Great! I know you've been hijacked here ..

Now ..back to the slugfest.


At loggerheads: Idiom Definitions for 'At loggerheads'
If people are at loggerheads, they are arguing and can't agree on anything.


I've concluded that these discussions are nothing but a frickin game for you. Everything I say, which by the way is usually correct, you find some way to twist it up in your head just to stir up sh*t. I could try to explain this stuff until I'm blue in the face and you would never admit that you're thinking is messed up on some of this stuff.

If you don't think an oil filter can contribute to flow restriction in the oil system, then go chew on this info for awhile. You like real test data ... right? Well, here ya go. As you can see (if you can read), is that each of those filters tested produced a different PSID across them with the same oil at the same flowrate. The PSID ranged from 6 to 16 psi dependant on the filter, with only flowing about 1.3 gpm of 10 deg C 10w-30 oil through them (relatively thick oil). I'm sure you'll twist something up to make it look like it was all done wrong, or the data is all bogus.

http://www.geocities.com/rfpxj/Oil_Filter_Experiment.pdf
Posted by: edhackett

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 03/24/09 12:49 PM

I think that spec is with no head on the pump. The pumps are positive displacement only in theory. They have clearances, as the pressure goes up the efficiency goes down.

FWIW, my WRX read ~100 psi cold, a common reading seen by those with gauges. This is above the 85 psi relief setting specified for the pump. Mine was reading at the top, back of the block in the main galley. This was essentially the greatest distance possible from the pump(lower front of engine). There is obviously a restriction to flow in the system.

Ed

Ed
Posted by: SuperBusa

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 03/24/09 01:05 PM

 Originally Posted By: edhackett
I think that spec is with no head on the pump. The pumps are positive displacement only in theory. They have clearances, as the pressure goes up the efficiency goes down.


That pump flow spec is with some kind of resistance on the output, otherwise the spec wouldn't specify it was at 43 psi discharge pressure. The 43 psi can't be a dead head output pressure, as it would certainly produce much more that 43 psi.

I have not seen any actual flow graphs of positive displacement pumps, and I'm sure there is some inefficiency on the top end, but if the pump is in good shape (ie, tight clearances) then IMO it's not going to lose much performance on the top end.

 Originally Posted By: edhackett
FWIW, my WRX read ~100 psi cold, a common reading seen by those with gauges. This is above the 85 psi relief setting specified for the pump. Mine was reading at the top, back of the block in the main galley. This was essentially the greatest distance possible from the pump(lower front of engine). There is obviously a restriction to flow in the system.

Ed


The only reason I could think of on why the oil pressure gauge would read higher than the pumps relief pressure setting is because it's possible the relief valve can not bypass all the excessive flow 100% effectively and that in turn will allow the pumps output to exceed the relief pressure setting. Imagine a relief valve that really didn't relieve very well ... where must the excess volume go? ... through the engine, which will increase the supply pressure because the pump is forcing more oil down the engine circuit because the relief valve didn't do it's job 100% as designed. This could certainly happen in a cold oil flow senario.
Posted by: SuperBusa

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 03/24/09 01:10 PM

 Originally Posted By: Gary Allan
 Quote:
You have to look at the entire SYSTEM to see what's going on.


I'm afraid that you don't. I don't have to know internal pump head or anything that you insist is essential to know/see the effects upon the filter. You seem to be unable to divorce Bernelli from the undeniable physical events and give them powers that aren't essential to understanding what occurs (more often then not).


You wouldn't know Bernoulli if he bit you in the arse! [censored], you can’t even spell it right.

Gary - I want to know why YOU think Subaru has specified a 23 psi relief setting on their oil filters. Tell us why if there is no pressure drop factor in a filter with high volume flow going through it.
Posted by: Gary Allan

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 03/24/09 07:02 PM

 Quote:
I've concluded that these discussions are nothing but a frickin game for you. Everything I say, which by the way is usually correct, you find some way to twist it up in your head just to stir up sh*t. I could try to explain this stuff until I'm blue in the face and you would never admit that you're thinking is messed up on some of this stuff.


I've concluded that these discussions are nothing but a frickin' game for you in self ego massaging. Everything I say, which, btw, is based 100% on real physical events, gets ignored and can't be envisioned nor integrated by your mindset and stubborn need to see garden hoses where none exist. I keep looking for you to bring something to the table that falls outside this one dimensional view ..and see nothing. You insist on twisting it back to a garden hose with applied pressure over a variable resistance ..which is not how the system reacts.

 Quote:
If you don't think an oil filter can contribute to flow restriction in the oil system,


Oh, here's where you fail the test 100% of the time. I've only insisted that a filter cannot alter the flow rate if the pump is not in relief.

You can read that statement, can you not? How does a pump producing 12gpm have its flow altered? Assuming it is not in relief, the pressures can vary ..but not the flow (again, for discussion's sake assume near 100% efficiency).

How hard is that to see?

Oh ..the link? Don't doubt the observed data at all. The guy surely isn't a liar. You've found another exceptional circumstance to bolster a flaw premise..

Flow can be altered...

BUT NOT WITHOUT CREATING ENOUGH RESISTANCE TO CAUSE A RELIEF EVENT AT THE PUMP.

This is a way exceptional event in millions upon millions of engine that putt-putt around in ignorant bliss and never see an appreciable PSID event beyond start up.
Posted by: Gary Allan

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 03/24/09 07:18 PM

 Quote:
FWIW, my WRX read ~100 psi cold, a common reading seen by those with gauges. This is above the 85 psi relief setting specified for the pump. Mine was reading at the top, back of the block in the main galley. This was essentially the greatest distance possible from the pump(lower front of engine).


Thank you for being one owner with a gauge. Your pump output, at startup visc, is in excess of what the engine and the relief can process and remain @ 85 PSI line pressure. You ARE in a garden hose scenario with the filter being limited in resistance to the flow being maxed @ 23 PSI ADDED to the circuit. Once you pull off of 85lb (as read off the pump)..there's no relief event ..that differential will retreat. If the sensor is downstream (which it appears that it is) then you would see 123+lb if you tapped in above the filter if your downstream is 100psi+/-.

 Quote:
There is obviously a restriction to flow in the system.


There is a resistance to flow passing an irresistible flow at a given rate(non-relief). It's evidenced by pressure elevations where the flow changes in velocity.

This is where SuperBusa (and just about everyone else) misses it.

5gpm through the Holland Tunnel
5pm though a capillary tube.

Once you accept that both DO IN FACT PASS THE FLOW ..the only difference is velocity and the pressure developed to do the job. Since we surrender to the (imperfections in pump efficiency ignored for discussion - making assertions MORE true than untrue)) fact that a positive displacement pump will pass a given volume at a given pump speed ..there's really not much else to argue with. The internal physics of the pump really doesn't need to enter into the discussion.
Posted by: Gary Allan

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 03/24/09 07:29 PM

 Quote:
Gary - I want to know why YOU think Subaru has specified a 23 psi relief setting on their oil filters. Tell us why if there is no pressure drop factor in a filter with high volume flow going through it.


I've stated this a few times ..but if you need a refresher..

Events @ 12.4 gpm = few
Events at startup relief = many


There are obviously limits to anything. The outlet port size of the pump will (probably) come into play at some point. I imagine that this is why pumps are typically rated with some terminal volume at some given pump speed. The internal pump outlet port, at some point, causes its own relief event. I've seen SBC racers machining out the gear side outlets to enable higher flow ...

So? How this upper strata limit alters flow is still missing in anything you've presented, SuperBusa.

12.4gpm @ 23 PSID at the filter
12.4gpm @ 11 PSID at the filter (non-spec)

The difference? 12.4gpm will be composed of more or less filtered oil depending on which filter you use...but it will still be 12.4gpm of flow.

Start up (and probably a good bit through the warm up event).

More oil will be filtered while limiting the maximum resistance to flow that a filter can present in a pressure over resistance flow scenario that is only possible in a pump relief event.
Posted by: SuperBusa

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 03/24/09 08:06 PM

 Originally Posted By: Gary Allan
 Quote:
I've concluded that these discussions are nothing but a frickin game for you. Everything I say, which by the way is usually correct, you find some way to twist it up in your head just to stir up sh*t. I could try to explain this stuff until I'm blue in the face and you would never admit that you're thinking is messed up on some of this stuff.


I've concluded that these discussions are nothing but a frickin' game for you in self ego massaging. Everything I say, which, btw, is based 100% on real physical events, gets ignored and can't be envisioned nor integrated by your mindset and stubborn need to see garden hoses where none exist. I keep looking for you to bring something to the table that falls outside this one dimensional view ..and see nothing. You insist on twisting it back to a garden hose with applied pressure over a variable resistance ..which is not how the system reacts.


You're the ego maniac here on this board ... I can sense it. You can't stand it if someone challenges your "supreme thoughts", and especially if they are right and you are wrong. You think you're always right, but there are plenty of things you don't quite grasp just yet, and frankly probably never will because you really do NOT understand fluid flow physics enough to see through your fogged up thoughts.

 Originally Posted By: Gary Allan
 Quote:
If you don't think an oil filter can contribute to flow restriction in the oil system,


Oh, here's where you fail the test 100% of the time. I've only insisted that a filter cannot alter the flow rate if the pump is not in relief.

You can read that statement, can you not? How does a pump producing 12gpm have its flow altered? Assuming it is not in relief, the pressures can vary ..but not the flow (again, for discussion's sake assume near 100% efficiency).

How hard is that to see?


This is where you don't get it - I have never claimed that the oil filter controls the flow rate through it. My claim is THAT THE FLOW THROUGH THE FILTER CAUSES A PRESSURE DROP ACROSS THE FILTER EMEMENT. When I say the words "FLOW RESTRICTION" I mean the filter is adding RESISTANCE TO FLOW. It does NOT mean that the filter is making the oil pump flow rate go DOWN ... you ARE ASSUMING THAT for some reason. Hence, this comes right around full circle with my claim (that you don't believe) that IF you put THE SAME FLOW RATE through a HIGHER FLOW RESISTANCE that the PSID across that resistance will INCREASE. Get it ???


 Originally Posted By: Gary Allan
If the pump is NOT in relief then ALL of its flowrate is going to the filter. Any you are claiming that with ALL the flow going through the filter that there isn't a significant PSID across the filter element? Come on man, are you serious?


Dude ... PLEASE re-read this stuff. See above ... you derailed some time ago it seems. I've ALWAYS CLAIMED that the MORE VOLUME YOU PUT THROUGH A FILTER THE GREATER PSID YOU WILL HAVE ACROSS THAT FILTER. Get a grip and learn how to frickin' read! And I'm NOT going to "hold your hand" and go back to point out every place I've described the physics. Instead, if you're so hot to prove me wrong, you can go back and find exactly where I've claimed differently.

 Originally Posted By: Gary Allan
Oh ..the link? Don't doubt the observed data at all. The guy surely isn't a liar. You've found another exceptional circumstance to bolster a flaw premise..

Flow can be altered...

BUT NOT WITHOUT CREATING ENOUGH RESISTANCE TO CAUSE A RELIEF EVENT AT THE PUMP.

This is a way exceptional event in millions upon millions of engine that putt-putt around in ignorant bliss and never see an appreciable PSID event beyond start up.


Don't get distracted from the test results. There was NO relief valve in the test. The pump was turned up until the SAME FLOW RATE was put through each filter, and then the PSID was seen. Obviously, not all filers are the same ... and they CAN have a somewhat significant PSID depending on the FLOW RATE and oil VISCOSITY going through them. And to add (and the reason for this thread), if the bypass valve is not set correctly for a filter's application then the PSID will be high enough to get unwarranted bypass events. This isn't rocket science, now is it?
Posted by: SuperBusa

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 03/24/09 08:40 PM

 Originally Posted By: Gary Allan
 Quote:
Gary - I want to know why YOU think Subaru has specified a 23 psi relief setting on their oil filters. Tell us why if there is no pressure drop factor in a filter with high volume flow going through it.


I've stated this a few times ..but if you need a refresher..

Events @ 12.4 gpm = few
Events at startup relief = many


There are obviously limits to anything. The outlet port size of the pump will (probably) come into play at some point. I imagine that this is why pumps are typically rated with some terminal volume at some given pump speed. The internal pump outlet port, at some point, causes its own relief event. I've seen SBC racers machining out the gear side outlets to enable higher flow ...

So? How this upper strata limit alters flow is still missing in anything you've presented, SuperBusa.


Sure, even a PDP can't have a linear output forever. But, I think the pump will perform relatively linear up to it's relief pressure setting. It wouldn't make sense to design a pump application for an engine that fell on it's face (output vs speed wise) way before the relief setting. If you believe that oil pump performance spec from Subaru, it says that the pump can put out 12.4 gpm at 5000 RPM. It also says that it takes 43 psi of pressure to push that 12.4 gpm of oil at 176 deg F (viscosity qualifier) through the oiling system of that Subaru engine - that gives you an idea of how restrictive the oil system is on that car ... not very IMO, otherwise it would take a whole lot more than 43 psi to flow that much oil warm through it. At least that's how I read it.

 Originally Posted By: Gary Allan

12.4gpm @ 23 PSID at the filter
12.4gpm @ 11 PSID at the filter (non-spec)


The difference? 12.4gpm will be composed of more or less filtered oil depending on which filter you use...but it will still be 12.4gpm of flow.

Start up (and probably a good bit through the warm up event).

More oil will be filtered while limiting the maximum resistance to flow that a filter can present in a pressure over resistance flow scenario that is only possible in a pump relief event.


I'm assuming you mean 23 and 11 psi bypass valves ... not PSID (see red).

The difference is, IF both filter's elements had the same resistance to flow, then the PSID should be the SAME in both filters if 12.4 gpm of flow is put through them both. The big difference then would be that the filter with the 11 psi bypass valve will go in to bypass much more often, and bypass events could happen even if the oil is relatively warm. This is the exact reason Subaru has specified a higher bypass valve setting ... to keep bypass events down to a minimum. Will it prevent them all? ... probably not - but, it will definitely keep the frequency down to a minimum.
Posted by: Thingfish

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 03/24/09 09:32 PM

I am a bit late but FWIW, 43 psi is the minimum pressure at 5K rpm.
 Originally Posted By: 2003 service manual

Oil pressure:
98 kPa (1.0 kg/cd, 14 psi) or more at 800 rpm
294 kPa (3.0 ks/cd, 43 psi) or more at 5,000
rpm


I see ~100 psi at cold start, and WELL more than 43 psi above 5K rpm, @ 180 oil temp, and around 20-25 psi at idle.

I have oil temp and pressure gauges.
Posted by: Gary Allan

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 03/25/09 07:38 AM

 Quote:
My claim is THAT THE FLOW THROUGH THE FILTER CAUSES A PRESSURE DROP ACROSS THE FILTER EMEMENT.


Only in exceptional circumstances. You some how "use" this to bolster the notion that it applies up and down the line. I assure you, it does not.

A filter is a virtual "still well" compared to the screaming galleries and passages. It crawls through the filter.

With a two lane road with a single lane exit as it's only outlet, how much does a section of 28 lane road inhibit traffic? A: Only when the 28 lane road is taxed by the rate of speed and number of cars. 99 44/100th % of those out see next to nothing.

You're finding physics that rarely applies and pretending, because you wish it to be true, that it works in all instances. It does not.


The Basic Test Fixture
The basic test fixture is made up of a positive displacement pump drawing oil from a
resevoir thru a test plate that can accommodate different modular adapters that the filter
will attach to and then discharging the oil back to the resevoir. The fixture has a pressure
gage on the inlet side of the filter and one on the outlet side of the filter. This setup is not
unlike the situation with a real oil pump in the motorcyle drawing oil from the sump, thru
the filter and then back to the sump. The inlet and outlet pressure gages would allow the
calculation of pressure drop across the filter and would also allow the calibration of the
outlet pressure gage to indicate flow rates.
Refer to APP I for a drawing of the test fixture and APP II for a photograph.


I don't quite get how the discharge tube simulates an engine.

Suppose the maximum oil flow was 1.1gpm?
Posted by: WagonBoss

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 03/25/09 05:40 PM

LoneRanger,
When you cut apart the OE filter and the 1365, could you discern any difference in the bypass valves? Is there a way to determine if one is "stiffer" just by feel?

One would think that UOA's would detect more wear if a filter was in bypass a lot. But, that does not appear to be the case as there is no additional apparent wear on these engines with a non-spec filter that I can tell just by looking at UOAs. The 2.5 NA engine just has good numbers with good oils.
Posted by: LoneRanger

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 03/25/09 05:47 PM

Yes, the Wix's bypass spring was easier to compress. Quite a bit easier. In order to compress the Wix's bypass valve I had to slip a socket fitting into it that was large enough to catch the bypass spring.
Posted by: SuperBusa

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 03/26/09 12:47 AM

 Originally Posted By: Gary Allan
 Quote:
My claim is THAT THE FLOW THROUGH THE FILTER CAUSES A PRESSURE DROP ACROSS THE FILTER ELEMENT.


Only in exceptional circumstances. You some how "use" this to bolster the notion that it applies up and down the line. I assure you, it does not.

A filter is a virtual "still well" compared to the screaming galleries and passages. It crawls through the filter.

You're finding physics that rarely applies and pretending, because you wish it to be true, that it works in all instances. It does not.


I really wouldn't go as far as saying the flow always "crawls" through an oil filter. Again, it all depends on what flow rate and viscosity of oil is going through the filter, the total surface area for that flow to go through, as well as the filter element resistance to flow. These are the parameters that will define what PSID is produced by across an oil filter.

The physics are there if you choose to believe it or not. For some reason you believe that every filter is a "still well" of oil where the oil if hardly moving through the filter ... I don't see it that way, because it's not always that way. If you actually flowed 12 gpm (even 6 gpm) of oil through a filter don't you think that is a pretty significant flow? - of course remember the viscosity factor has an effect too. I can agree that if it's a 1 or 2 gpm, then it's a whole different story then 6 or 12 gpm; but the fact remains that any flow will technically produce a corresponding PSID, even if it's a small one. There are certainly conditions where the filter PSID is significant ... you can't argue that fact.

 Originally Posted By: Gary Allan

The Basic Test Fixture
The basic test fixture is made up of a positive displacement pump drawing oil from a resevoir thru a test plate that can accommodate different modular adapters that the filter will attach to and then discharging the oil back to the resevoir. The fixture has a pressure gage on the inlet side of the filter and one on the outlet side of the filter. This setup is not unlike the situation with a real oil pump in the motorcyle drawing oil from the sump, thru the filter and then back to the sump. The inlet and outlet pressure gages would allow the calculation of pressure drop across the filter and would also allow the calibration of the outlet pressure gage to indicate flow rates.
Refer to APP I for a drawing of the test fixture and APP II for a photograph.


I don't quite get how the discharge tube simulates an engine.

Suppose the maximum oil flow was 1.1gpm?


In that filter test, the objective was to compare the flow characteristics of various filters by looking at their PSID while flowing the same oil volume and viscosity through each filter. As you can see, there were some significant PSIDs (up to 16 psi) while flowing just about 1.3 gpm (5.25 liter/min). The oil was 10w-30 and only at 10 deg C, so it was relatively viscous. Sure, if the oil was hot and thin, then the PSID might have only been 1~2 psi instead of 16 psi.

The test setup was not meant to simulate and engine, but it really doesn't matter because if you flowed 1.3 gpm through those filters regardless if they were on a test rig like that, or actually on an engine, then there would still be 1.3 gpm going through them which would give you the same PSID he saw. The PSID produced by the filter was solely a function of the oil volume and viscosity of the oil going through it ... and of course the total design of the filter assembly. Not all filters flow the same while under the same exact flow conditions - this test proved that.

Link to reference test:
http://www.geocities.com/rfpxj/Oil_Filter_Experiment.pdf
Posted by: Gary Allan

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 03/26/09 02:12 AM

 Quote:
If you actually flowed 12 gpm (even 6 gpm)


Both of which are extremes for most engines.

IF your aunt had testicles, she'd be your uncle. You default to the extreme because it supports your assumptions about filters that don't apply more than they ever could apply.

When you're average stroke says that he chose a given filter because it was more "free flowing" ..he's not talking about flat shifting @ 7000 rpm or running flat out on the track.

You have to be young or living out of some Jeg's catalog.

 Quote:
I really wouldn't go as far as saying the flow always "crawls" through an oil filter.


..and I will not require you to...

Relative to the velocity out of the pump and through to the main gallery, it is a crawl. Now you can cite the squeezing through the pores in the media ..but there is a tremendous deceleration of fluid that enters the filter (on average, anyway). I'm pretty sure that it shears as it descends into the filter (spinflow's excluded).

60mph is crawling on the autobahn.

 Quote:
In that filter test, the objective was to compare the flow characteristics of various filters by looking at their PSID while flowing the same oil volume and viscosity through each filter.


You're giving too much credit to filter resistance since you can't seem to see how much the reactive component of viscosity plays in the picture. A filter can (probably) be reduced to one larger orifice. The turbulent pressure alterations on the companded (compressed and expanded) flow squeezing through it are not linear and have some disproportionate impact on PSID as either flow increases or viscosity is high. Most of this is still a non-factor in many more instances than not since the viscosity also increases the apparent resistance of the engine, which the filter must be subordinate to in total circuit resistance.

Under this filter's testing:

18-Oct-03 10 Fram PH30 20 13.25 6.75 5.26 1.4444 2.024 New

..the engine would always be 2/3 of the relative resistance to the filter. Choke the outlet at the same volume to where the downstream pressure was 9/10th of the supply pressure ..and those figures would not be the same.

That is, whatever pressure is developed in the acceleration of the oil through the collective orifices of the filter, generally speaking, is minor to what pressure is developed accelerating the oil through the engine. You can probably exchange "power required as evidenced by pressure alterations" if you'll entertain the notion. In a positive displacement environment, nothing flows faster. It may flow easier.

Again, while not specifically manipulated for proving your point, it's misleading. It can only be used in a comparative manner for most sensible views.

It's not that simple.
Posted by: SuperBusa

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 03/26/09 04:09 AM

 Originally Posted By: Gary Allan

You're giving too much credit to filter resistance since you can't seem to see how much the reactive component of viscosity plays in the picture. A filter can (probably) be reduced to one larger orifice. The turbulent pressure alterations on the companded (compressed and expanded) flow squeezing through it are not linear and have some disproportionate impact on PSID as either flow increases or viscosity is high. Most of this is still a non-factor in many more instances than not since the viscosity also increases the apparent resistance of the engine, which the filter must be subordinate to in total circuit resistance.


When you flow oil through a filter and measure the flow rate and PSID, whatever that (supposed) phenomena you tried to describe above is contributing to the PSID generated. Flow is flow ... PSID is PSID ... it doesn't matter how the PSID is generated. The flow and PSID are directly related to each other through the flow characteristics of the fluid and filter. This holds true for any other restriction a fluid flows through - orifice, venturi tube, small tubes, main bearing, etc, etc.

 Originally Posted By: Gary Allan
Under this filter's testing:

18-Oct-03 10 Fram PH30 20 13.25 6.75 5.26 1.4444 2.024 New

..the engine would always be 2/3 of the relative resistance to the filter. Choke the outlet at the same volume to where the downstream pressure was 9/10th of the supply pressure ..and those figures would not be the same.


Well of course not. If you choke the flow down to a trickle then you essentially make every pressure drop a very small amount. And if you plugged the outlet all together there would be zero pressure drop anywhere because the flow would be zero. So what's the point? Don't you believe a filter can flow 1.3 gpm of cold oil?

I really want to know how you came up with the theory that:

"Under this filter's testing:

18-Oct-03 10 Fram PH30 20 13.25 6.75 5.26 1.4444 2.024 New

..the engine would always be 2/3 of the relative resistance to the filter."


 Originally Posted By: Gary Allan
That is, whatever pressure is developed in the acceleration of the oil through the collective orifices of the filter, generally speaking, is minor to what pressure is developed accelerating the oil through the engine. You can probably exchange "power required as evidenced by pressure alterations" if you'll entertain the notion.


Pressure is not developed by accelerating the oil. Is that what you really mean? Are you saying that when a fluid goes through something like a small orifice that more pressure is created out of magic somehow? It's just a strange way to word something. In actuality, pressure is produced solely by the pump based on how much flow is being forced through a fixed resistance path. As the flow progresses through the flow path, pressure is being lost all along the path from start to finish. Each pressure drop along the way is dependent on each specific restriction found throughout the flow path. As you know, all the specific pressure drops must at up to the supply pressure since the flow is exiting at ATM pressure (0 gauge psi). A filter drops the pressure slightly, the main bearings drop the pressure a lot, lifters drop is some, cam bearings, etc, until the oil exits out into the engine's sump where the pressure is zero psi.

 Originally Posted By: Gary Allan
In a positive displacement environment, nothing flows faster. It may flow easier.


Not real sure what you're after with that statement. The positive displacement flow will change velocity accordingly as it goes through small or large cross sectional areas throughout the flow path. When it goes into a small tube it's flow speed increases (it will be "screaming" as you've said before) ... when it goes in a big cavity the flow speed decreases (in to a big oil filter can for instance). Isn't this basically what you've described before? Guess what ... this is exactly Bernoulli's effect. I knew you'd like that tid-bit. ;\)

 Originally Posted By: Gary Allan
Again, while not specifically manipulated for proving your point, it's misleading. It can only be used in a comparative manner for most sensible views.


Yes, that filter test was for "comparative purposes". I don't think it's misleading at all. The fact is, oil filters create a pressure drop across them with flow - it is that simple. And actually, flowing 1.3 gpm of 10w-30 oil at 10 deg C through an oil filter does seem pretty realistic to me. Until you can rig up an accurate flow meter and filter delta-P gauge on a car that puts out some decent oil pump volume, and show me the actual oil flow rate and corresponding PSID with engine at high RPM with cold oil ... only then I might say the pressure drop across an oil filter is negligible IF the PSID is small. Otherwise, I'm betting it's going to be much more than you think it is.
Posted by: Gary Allan

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 03/26/09 08:01 AM

 Quote:
If you choke the flow down to a trickle then you essentially make every pressure drop a very small amount. And if you plugged the outlet all together there would be zero pressure drop anywhere because the flow would be zero. So what's the point? Don't you believe a filter can flow 1.3 gpm of cold oil?


Did I say reduce flow? A river, traveling through a rapids or flat, has no change in flow rate. The velocity, and the "choke" is altered.

 Quote:
I really want to know how you came up with the theory that:

"Under this filter's testing:

18-Oct-03 10 Fram PH30 20 13.25 6.75 5.26 1.4444 2.024 New

..the engine would always be 2/3 of the relative resistance to the filter."


How hard is it for you to understand that you have two resistors in a ratio to each other. Apply any pressure you want ...pass any current and the ratio will be the same (reactive elements, if any, ignored for the moment).

(applying your style) Anyone knows that. Are you saying that this is something new to you? The model the tester presented had 2/3 pressure down stream of the filter ...or (would be) engine.

Now, add a substantial restriction to the downstream (no difference in flow) ..and that PSID will compress. The pressure dissipated accelerating the oil through the orifice of the filter will be minor compared to the pressure dissipated over the engine accelerating the oil through it.

Under your universal model, if there was no outlet restriction, while the input pressure would be reduced, the input pressure would also be the PSID. Let's say it was 5. Are you saying that, as you kept the flow state constant, that THAT 5PSID would be maintained ..regardless of how you effected total pressure by reducing the cross section of the outlet (or lengthened it)??

Flow is flow, right? No. Those pressure alterations would be in ratio to each other.

 Quote:
Pressure is not developed by accelerating the oil. Is that what you really mean?


Are you saying that you ARE this one dimensional and can't think one inch outside the box in alternative thinking?

Drop or develop ..it's the same thing. The difference is that in a positive displacement situation it's more indicative of the physical events taking place. As you add restriction, through viscosity ..the pressure is "backed up". YES ..the internal pump pressure (A VARIABLE AMOUNT DEPENDING ON WHAT RESISTANCE IT SEES) is "developed" over the restriction. This is a common term with high impedance inputs and whatnot. It would be hard to imagine that you're this educated without integrating this.

Stating it this way you avoid looking at it like a water faucet or garden hose. You merely regard it as a flow dictated circuit ..which it is. Everything else will be variable ..but NOT THE FLOW. Resistance will be variable with viscosity ..pressure will vary with resistance. FLOW is the only fundamental that alters the other two ..the other two cannot alter flow. Here's where you're seeing what you want to see. 1 gpm is still 1 gpm. The pressure and resistance will vary ..but 1 gpm is still 1 gpm. It never changes from one gpm (use whatever number you please). When I say flow dictated circuit ..it is at any flow rate. Take any rate you please, just consider it a constant in THAT moment. The pressure, a component of resistance under flow, will VARY. The flow, will not change and will be the ULTIMATE determining factor of WHAT pressure is seen based on the FLOW passing through the resistance AT THAT TIME.

 Quote:
As the flow progresses through the flow path, pressure is being lost all along the path from start to finish.


Sure, you can state it this way, except that if you added additional resistance, you would also add additional pressure. Hence the concept of "loss" is not indicative of the physical events taking place. You're "adding" resistance ..and therefore, adding additional pressure to the circuit.

If I add resistance, does the supply pressure approach closer the the relief limit ..ie GO UP? YES OR NO? See how easy that was to see?? Did I, in doing so, "develop" more pressure?? YES OR NO?

This is not all that hard to grip. You can cite anything you please, but there is nothing "wrong" with using those terms ..which MUCH more clearly show the physical events as they occur. You can complicate it if it makes you feel better.

 Quote:
Not real sure what you're after with that statement.


It's very simple. 1 gpm is 1 gpm. The difference will be the power required to move it. That stress, power, pressure, force ..may vary. The flow does not. Got an argument with that?

 Quote:
Until you can rig up an accurate flow meter and filter delta-P gauge on a car that puts out some decent oil pump volume, and show me the actual oil flow rate and corresponding PSID with engine at high RPM with cold oil ... only then I might say the pressure drop across an oil filter is negligible IF the PSID is small. Otherwise, I'm betting it's going to be much more than you think it is.


Ah ..so I need an accurate flow meter to be "true", huh?

Normal differential gauges and upstream downstream pressures won't be valid on any engine ..under any conditions ..and even if they were, would be in no way indicative of what any engine/filter combination sees at any time.


I see

Next!



The only time a filter can be a factor in terms of resistance is at the extremes. Take any size conduit that you want ..make it as big as you want. Move ENOUGH stuff through it and it will eventually become a factor. The likelihood of this occurring in the vast majority of engine/filter combo's is nil.

There will always be exceptions. Unless your exceptional ..or special ..(along with your education) ..I doubt you'll ever need to worry about it.
Posted by: Gary Allan

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 03/26/09 08:23 AM

 Quote:
Pressure is not developed by accelerating the oil. Is that what you really mean?


Let me expand on this a moment (edit time - I need to do this pony style).

Let's go back here:

1gpm passing through a 1/2" pipe
1gpm passing through a 1/4" pipe

What's the difference?

Velocity and pressure (I'll leave it in your terms)

Got that?

Good.

Now put the 1/4" pipe on the end of the 1/2" pipe. What MUST the fluid do upon encountering the 1/4" pipe? Hint: It ACCELERATES!!!!!. Now it has about 3X the velocity. The pressure reading, at the point of transition, is the force/power/whatever required to accelerate the fluid to that flow rate ..over that length of conduit ...because ..it's a flow dictated circuit of 1gpm (for no other reason that I say so for this demonstration). The velocity will vary ..the pressure will vary ..but the flow will be constant. Now apply any flow rate you want, and the view is the same. The pressure is how velocity and/or acceleration is expressed in a positive displacement environment.

Tell me you've never used analogs? This is no more or less than that.

You can view it in your terms if you please, but there's nothing wrong with what I just said. It's far more indicative of the physical events as they occur.

Simple enough??
Posted by: SuperBusa

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 03/26/09 08:24 PM

 Originally Posted By: Gary Allan

How hard is it for you to understand that you have two resistors in a ratio to each other. Apply any pressure you want ...pass any current and the ratio will be the same (reactive elements, if any, ignored for the moment).

(applying your style) Anyone knows that. Are you saying that this is something new to you? The model the tester presented had 2/3 pressure down stream of the filter ...or (would be) engine.

Now, add a substantial restriction to the downstream (no difference in flow) ..and that PSID will compress. The pressure dissipated accelerating the oil through the orifice of the filter will be minor compared to the pressure dissipated over the engine accelerating the oil through it.


I’m really getting tired of going round-n-round with you on the same old bullsheeeet. Seems you are all over the place with your thinking at times. Makes it real hard to have any kind of constructive discussion.

So, let’s use your system “resistance ratio” thoughts. Yeah, I agree and fully understand that there is a total resistance of the flow path which is the sum of the filter resistance plus the engine resistance. If you don’t agree with that, then you don’t agree with yourself, which actually has happened in these discussions because you’ve contradicted yourself more than a few times. ;\)

So, let’s say an oil pump has a relief valve setting of 120 psi. Let’s say the pump is supplying oil flow at 100 psi (it’s not in relief). Let’s say that the engine’s flow path is 9/10 ths of the total system flow restriction, and the oil filter is only 1/10 th. So, that means there would be 10 PSID across the filter and 90 PSID across the engine in this particular case ... for a total pressure loss = 100 psi, which is the difference between the pump supply pressure and the exit pressure of 0 psi at the sump.

The 10 PSID across the filter in this case is certainly measureable and could be significant IF the filter’s bypass was not set correctly for a particular vehicle application.

Let’s go a step further and look at this Subaru oiling system in this case. Since the oil system specs say that it can flow 12.4 gpm at 43 psi with 176 deg F oil, this tells me right off that the engine’s flow path is not very restrictive. Let’s say it is 4/5 ths the total system restriction, and the filter is 1/5 th. So the max flow and hence max pressure drops throughout the system will occur when the oil pump is in relief mode – 85 psi in this case. So we have 85 psi to dissipate from inlet to outlet of the oil flow path. So, if 4/5 ths of the flow is dissipated in the engine, then 1/5 th is dissipated in the filter. This means there is a 17 PSID across the filter and a 68 PSID across the engine flow circuit in this particular flow case. In the Subaru example, the estimated 17 PSID is only 6 psi below the filter’s bypass setting of 23 psi.

The bottom line is still the fact that the more flow you put through a fixed flow resistance (including an oil filter – crazy isn’t it that even a filter must obey the laws of fluid flow ;\) ), the more pressure drop (PSID) you will see. In the case of the Subaru example, it can be seen that the more free flowing the system is (less restriction), and higher volume output the oil pump has, the more filter PSID you will achieve. Again, that is why Subaru has specified a 23 psi bypass valve on their oil filter for this car.

 Originally Posted By: Gary Allan

Under your universal model, if there was no outlet restriction, while the input pressure would be reduced, the input pressure would also be the PSID. Let's say it was 5. Are you saying that, as you kept the flow state constant, that THAT 5PSID would be maintained ..regardless of how you effected total pressure by reducing the cross section of the outlet (or lengthened it)??

Flow is flow, right? No. Those pressure alterations would be in ratio to each other.


No, I’m not saying what’s shown in red text in your quote. IF you “reduced the cross section of the outlet” then you have INCREASED the resistance to flow. When you increase the resistance to flow but DON’T CHANGE the flow rate, the ONLY thing that can happen is a HIGHER PSID will be produced. This is exactly why a filter with a more resistive element produces a higher PSID with the same flow conditions. That is exactly what that motorcycle filter test proved.

Anyway ... can’t address everything you’ve spit back at this point. I spend way too much time going “round ‘n round” with this stuff as it is.
Posted by: Gary Allan

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 03/27/09 04:43 AM

 Quote:
So, let’s use your system “resistance ratio” thoughts. Yeah, I agree and fully understand that there is a total resistance of the flow path which is the sum of the filter resistance plus the engine resistance. If you don’t agree with that, then you don’t agree with yourself, which actually has happened in these discussions because you’ve contradicted yourself more than a few times. ;\)


No problem.

 Quote:
So, let’s say an oil pump has a relief valve setting of 120 psi. Let’s say the pump is supplying oil flow at 100 psi (it’s not in relief). Let’s say that the engine’s flow path is 9/10 ths of the total system flow restriction, and the oil filter is only 1/10 th. So, that means there would be 10 PSID across the filter and 90 PSID across the engine in this particular case ... for a total pressure loss = 100 psi, which is the difference between the pump supply pressure and the exit pressure of 0 psi at the sump.


No problem.

 Quote:
The 10 PSID across the filter in this case is certainly measureable and could be significant IF the filter’s bypass was not set correctly for a particular vehicle application.


No problem if that's what it is.

So? You've just magically produced a scenario where you have 10 PSID across the filter. Why not 20..30..40?

(sigh) ....How do I know that 100 psi applied to a given filter will produce the 9/10 split between the engine and the filter? How do you know it? You don't. My point was in regard to the test that you cited as living proof of your assertions was setup in a manner where there would always be a sizable PSID across the filter since the downstream pressure (with all the usual caveats) was always going to be around 65%. Raise or lower volume to produce a bypass event. Very easy to produce PSID ..and therefore easy to "make" a bypass event.

 Quote:
Let’s go a step further and look at this Subaru oiling system in this case. Since the oil system specs say that it can flow 12.4 gpm at 43 psi with 176 deg F oil, this tells me right off that the engine’s flow path is not very restrictive.


No problem ..so far.. again, you default at the extreme for whatever reason you need to. I can't quite figure how this applies to too much outside of that narrow confine ..but let's go back and rehash it. I tend to agree with this, but with you it's merely a setup for something that won't necessarily flush.

 Quote:
Let’s say it is 4/5 ths the total system restriction, and the filter is 1/5 th.


When? I see you constructing a given pre-packaged scenario here. Try and define the difference between revealing something, and configuring something to work out the way you want it to.


 Quote:
So the max flow and hence max pressure drops throughout the system will occur when the oil pump is in relief mode – 85 psi in this case.


How do you figure? In relief mode:

A: You have less than max flow
B: You DO have max pressure applied
C: You can have 85lb and be in relief at virtually NO VOLUME to the engine (startup and until the fluid gets moving).

You haven't qualified the conditions well enough. You've just stated that something is so without thinking it out too far.

Maximum possible flow will go to the engine (whatever that may be). Maximum pressure is applied (and can be exceeded). The difference between flow at 85lb in relief and 85lb out of relief will be the difference between the flow seen by the engine vs. the total flow output of the pump. The difference in pressure (drop, if you must) across the engine (due to the flow passing through it) and the pressure applied will determine the pressure differential across the filter. Once the flow is unified (a single flow) the engine will drop (if you insist) more pressure due to more flow going through it (buffoons will admit this) ..YET THE APPLIED PRESSURE WILL REMAIN THE SAME @ 85LB OUT OF RELIEF.


The differential across the filter will evaporate to next to nothing.

A CHILD CAN REASON THIS (at this point, anyway).

None of the above has once challenged the flow limitations of the filter. You seem to obsess on this aspect of the filter that is so rare ..all for what?



That's enough for now. Yes, if he's going to operate @ 5000 rpm ..he'll need a higher bypass rated filter just as much as he does while he's in relief (many ..many..many more times) at cold start and through the warm up process ...and most of it from idle through the point of dropping below 85lb of pressure regardless of the volume output of the pump for a goooooooood long way up to peak volume capability.













Posted by: Gary Allan

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 03/27/09 05:26 AM

Let me give you this last demonstration here

We'll use the following givens (adjust as needed)

85lb relief limit
23lb bypass valve setting


85lbs in relief

Maximum differential across filter 23lb

Readings (not given for the truth in a Subaru - only stating it for a generic 85lb relief limit pump and "a filter" with a 23lb bypass valve:

Reading above/below filter

85 - 23 = 62lb across engine. Got that? Good.

Now what occurs when MORE flow is channeled to the engine as less flow exits the relief port returning to either the sump or the suction side of the pump

85lb - (?) = MORE THAN 62lb due to more flow - filter can NO LONGER DROP 23lb
Increase flow

85lb - (?)= EVEN CLOSER TO 85lb due to even more flow through the engine. Filter drops even less than before.

85lb -(?) engine pressure drop increases EVEN MORE and approaches EVEN closer to the PEAKED 85 EFFFIN POUNDS

AND THE SUPPLY IS STILL 85 EFFIN Pounds!!! Where did the PSID go? It evaporated!!!!!!


QED

Please ..no more ..
Posted by: SuperBusa

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 03/27/09 06:28 PM

 Originally Posted By: Gary Allan

So? You've just magically produced a scenario where you have 10 PSID across the filter. Why not 20..30..40?

(sigh) ....How do I know that 100 psi applied to a given filter will produce the 9/10 split between the engine and the filter? How do you know it? You don't.


Agreed ... NOBODY knows unless they do some flow vs. pressure testing with instrumentation on an actual vehicle’s oiling system – so neither one of us can claim they know the real split. You have “guesstimated” a few times yourself. But at least the example gives an ideal of how the filter vs. engine resistance ratio to oil flow will play a part on how an oil filter


 Originally Posted By: Gary Allan

My point was in regard to the test that you cited as living proof of your assertions was setup in a manner where there would always be a sizable PSID across the filter since the downstream pressure (with all the usual caveats) was always going to be around 65%. Raise or lower volume to produce a bypass event. Very easy to produce PSID ..and therefore easy to "make" a bypass event.


The key to all of these discussions is that certainly are instances when there can be enough PSID across a filter to create unwanted bypass events. This is why it’s so important that an oil filter has a bypass setting designed adequately for the application the filter is for. Subaru specifying a 23 psi bypass valve reflects just that ... because if it was set much lower (like 8-10 psi), then there are going to be WAY more bypass events going on, which could be detrimental in the long run.

The cycle filter testing IMO wasn’t so far removed for practicality. Do you think an engine could flow 1.3 gpm of cold (10 deg C) 10w-30 oil during a cold start/run use? I think it could ... and therefore, any of those tested oil filters on an engine that could produce that same flow would show the same PSID as in that bench test. Some of those PSIDs were probably up at or very close to the bypass setting. So, there really isn’t a big surprise there, as I’m sure there are thousands of oil filters in use that go into bypass mode to some degree during cold start/run use. The frequency and level of the bypass events is still dependant on the overall flow design of the oil filter AND engine’s oiling system, and how they both work together as a system.


 Originally Posted By: Gary Allan

 Quote:
Let’s go a step further and look at this Subaru oiling system in this case. Since the oil system specs say that it can flow 12.4 gpm at 43 psi with 176 deg F oil, this tells me right off that the engine’s flow path is not very restrictive.


No problem ..so far.. again, you default at the extreme for whatever reason you need to. I can't quite figure how this applies to too much outside of that narrow confine ..but let's go back and rehash it. I tend to agree with this, but with you it's merely a setup for something that won't necessarily flush.




 Originally Posted By: Gary Allan

 Quote:
Let’s say it is 4/5 ths the total system restriction, and the filter is 1/5 th.


When? I see you constructing a given pre-packaged scenario here. Try and define the difference between revealing something, and configuring something to work out the way you want it to.


You’re kind of paranoid I see. ;\) Of course a scenario has to be “constructed” to get point across. You do it all the time too. I don’t think it’s that unrealistic. It doesn’t have to be 100% realistic to describe the physics.


 Originally Posted By: Gary Allan

 Quote:
So the max flow and hence max pressure drops throughout the system will occur when the oil pump is in relief mode – 85 psi in this case.


How do you figure? In relief mode:

A: You have less than max flow
B: You DO have max pressure applied
C: You can have 85lb and be in relief at virtually NO VOLUME to the engine (startup and until the fluid gets moving).

You haven't qualified the conditions well enough. You've just stated that something is so without thinking it out too far.


OK, let me explain. Please realize that anytime the oil pump is in relief mode that this point is where the max flow to the filter/engine circuit occurs – depending on the oil viscosity of course. This is kind of tricky to comprehend (and describe too), so stay with me.

Your item A) above. Yes, when the oil pump is in relief mode “you have less than max flow” ... BUT really only less than the possible max the pump could have produced IF it wasn’t in relief mode. Since it IS in relief mode, then the oil volume that actually goes through the filter/engine flow path IS the maximum you can ever achieve (with xyz oil viscosity of course) because this is the maximum pressure that can ever be put on the system. With higher pressure you get more flow. So, max flow ALWAYS happens when the oil pump is putting out max pressure at its relief setting. Keep in mind that the oil pump COULD produce more pressure and flow if it could go above the relief point.

Your item B) above. Yes, agreed. And just as I explained above, this also correlates to having the max possible flow going to the filter/engine. The pump DOES put out more flow, but the excess volume gets spit back to the sump, and the volume going to the filter/engine remains constant at the pumps relief pressure point.

Your item C) above. Same principle. In the case you site in item C), you are still at the max flow that is POSSIBLE under those conditions. In other words, you can NOT flow more than what will flow with 85 psi trying to push the oil through the flow path. We both know that as the oil starts warming up, the then the actual flow VOLUME will also increase. Imagine the oil pump is in relief mode at 85 psi instantly from cold start to full oil temp. Of course the flow volume will be a lot smaller at cold start then at full operating temperature ... BUT, during the whole warm-up period, the MAX POSSIBLE flow to the filter/engine was always maxed out because the oil supply pressure was always at the max possible of 85 psi. Look at it from the supply pressure point just downstream of the relief valve. Look at the pressure and flow volume at that point, not at the point between the oil pump and relief valve.


 Originally Posted By: Gary Allan

Maximum possible flow will go to the engine (whatever that may be). Maximum pressure is applied (and can be exceeded). The difference between flow at 85lb in relief and 85lb out of relief will be the difference between the flow seen by the engine vs. the total flow output of the pump.


Well, IMO ... “technically”, the flow coming out of the pump right at the 85 psi relief point is just on the verge of splitting between the filter/engine and sump. This is a bad pressure to talk about flow split because the spit is ill defined right at the relief setting. We both know and could say that if the pump outlet was say between 1 and 80 psi then there should be no slit, and all the pump’s output volume goes to the filter/engine. But if the pump’s output pressure hit 85 psi, and the pump’s RPM was then still increasing at this point, (remember that a PD pump’s RPM is key here), then the oil pump WILL put out more volume, but any volume in excess of what can be pushed through at 85 psi to the filter/engine will be spit out the relief valve to the sump.


 Originally Posted By: Gary Allan

The difference in pressure (drop, if you must) across the engine (due to the flow passing through it) and the pressure applied will determine the pressure differential across the filter. Once the flow is unified (a single flow) the engine will drop (if you insist) more pressure due to more flow going through it (buffoons will admit this) ..YET THE APPLIED PRESSURE WILL REMAIN THE SAME @ 85LB OUT OF RELIEF.

The differential across the filter will evaporate to next to nothing.

A CHILD CAN REASON THIS (at this point, anyway).

None of the above has once challenged the flow limitations of the filter. You seem to obsess on this aspect of the filter that is so rare ..all for what?


Now, now ... I’m sure a child would actually have no idea whatsoever what any of this discussion means. I haven’t seen but a few comments made from other members here with regards to our detailed discussions, so apparently either everyone else besides you and me fully understand it, or else they don’t want to even get involved because they don’t understand it.

I think you’ve mis-read or misinterpreted (“read between the lines”) some things I’ve tired to say in some of these discussions. All of my discussions and examples are assumed to be after the engine has started and the oil pressure has come up and has filled every nook and cranny of the oiling system with flowing oil – ie, “steady oil flow” conditions. I really don’t care about the instantaneous physics going on here – ie, starting a cold engine with a dry filter and engine galleys not filled up.

You think that “the difference across the filter will evaporate to next to nothing”. Well, it really DEPENDS on a number of things. As we have hashed over more than once on this, the engine’s oil flow path resistance will dominate in determining exactly what flow rate goes through the filter/engine flow path. No agreement there ... and YES, the engine flow path WILL be more restrictive than the oil filter ... BUT, just how much more? This is the KEY to this whole discussion. Not every engine will have the same flow resistance. The Subaru in question obviously seems to have an oiling system that is quite a bit less restrictive than most cars on the road, and this DOES play a part on how the oil filter must be designed for an engine application like this. That has been my main focus in these discussions all along. Yeah, it might be it a so called “rare case”, so why always try to divert from this and always assume it’s like all the other cars on the road? – I’m not claiming that EVERY oil filter might have some flow/PSID/bypass issue.

But in a “rare case” like this, the flow limitations of the filter could certainly be “challenged” by the application – that specifically being that using a filter with the wrong bypass setting on an engine like the Subaru could certainly cause excessive bypass events, which could lead to other problems as one member posted about (debris in the turbo oil line screen filter that eventually chokes oil to the turbo and smokes it.).


 Originally Posted By: Gary Allan

That's enough for now. Yes, if he's going to operate @ 5000 rpm ..he'll need a higher bypass rated filter just as much as he does while he's in relief (many ..many..many more times) at cold start and through the warm up process ...and most of it from idle through the point of dropping below 85lb of pressure regardless of the volume output of the pump for a goooooooood long way up to peak volume capability.



WTF? ... I can’t believe it, after all of that. You’ve just confirmed what I’ve been claiming (and have said) all along! It’s a miracle!
Posted by: SuperBusa

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 03/27/09 07:05 PM

 Originally Posted By: Gary Allan
Let me give you this last demonstration here

We'll use the following givens (adjust as needed)

85lb relief limit
23lb bypass valve setting

85lbs in relief

Maximum differential across filter 23lb

Readings (not given for the truth in a Subaru - only stating it for a generic 85lb relief limit pump and "a filter" with a 23lb bypass valve:

Reading above/below filter

85 - 23 = 62lb across engine. Got that? Good.

Now what occurs when MORE flow is channeled to the engine as less flow exits the relief port returning to either the sump or the suction side of the pump


Gotta jump in right here. Here’s the clincher. There can NOT be more flow going to the filter/engine if the pump goes below relief pressure and puts out less pressure than 85 psi – it is impossible. The basic phenomena that causes the pump to go into bypass is the fact that the pump’s outlet pressure is increasing (due to trying to force the oil down a path of resistance) as the pump's output volume increases due to running it at a higher and higher RPM. That's the whole principle behind a PD pump ... it's output volume is basically a liner function of the RPM it is driven at.

This could be were some of you thinking is off. You see, the more supply pressure there is coming out of an oil pump, then the more flow there will be due to running it at higher and higher RPM (everything else being constant – keep that in mind). There can NOT be more oil flow at a supply pressure of say 70 psi (pump out of relief mode) than at 85 psi (pump at or well into relief mode). This is because (read carefully) as the pump goes below 85 psi, the flow will also decrease accordingly (assuming everything else is constant like the circuit resistance and oil viscosity). Remember with a PD pump, the output volume is a function of it’s RPM.

The oil pump can NOT force any more flow down a fixed resistance path when it’s output pressure is below the relief pressure. The max oil flow through a fixed resistance path will ALWAYS occur when the oil pump is in relief mode. The max flow volume through the filter/engine circuit occurs at pump relief and that volume will remain CONSTANT from that RPM and above because the pump output pressure is constant at 85 psi. The rest of the EXCESS PUMP VOLUME (created from higher PRM) is spit back to the sump by the relief valve, and that volume of spit back oil is the only stream in the total pump output that increases with increased engine RPMs. Think about it ... you will see it.

 Originally Posted By: Gary Allan

85lb - (?) = MORE THAN 62lb due to more flow - filter can NO LONGER DROP 23lb
Increase flow

85lb - (?)= EVEN CLOSER TO 85lb due to even more flow through the engine. Filter drops even less than before.

85lb -(?) engine pressure drop increases EVEN MORE and approaches EVEN closer to the PEAKED 85 EFFFIN POUNDS

AND THE SUPPLY IS STILL 85 EFFIN Pounds!!! Where did the PSID go? It evaporated!!!!!!

QED

Please ..no more ..


I really didn’t quite follow your thoughts on the rest here – I think you derailed some on this one. Based on what I wrote above, the ONLY time the supply pressure can be at 85 psi is when the oil pump in relief mode. And as described above, if the filter/engine circuit and oil viscosity remain constant, then so does the oil volume going through the filter/engine if the pump is always in relief mode. If the supply pressure is in relief mode at 85 psi, then the flow through the filter/engine is the highest possible (for any given constant visosity of course). If the supply pressure is say 40 psi (due to lower RPM), then the flow through the filter/engine is less. There is WAY LESS oil volume going through the filter/engine at idle or low RPM (WAY below pump relief) than at redline when the pump maybe WELL INTO relief mode.

Are we converging yet? ... does your head hurt? ;\) Man, this is getting way down into grass roots ... something has to come out of it.
Posted by: Gary Allan

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 03/27/09 07:16 PM

 Quote:
Please realize that anytime the oil pump is in relief mode that this point is where the max flow to the filter/engine circuit occurs


Well, I fully realize what occurs when a pump is in relief, I've observed it first hand personally I'll assume that you're not qualifying this (left it out) that we're not only fully enveloped, but that all effects of taking a static oil column to max flow capability has been achieved.

 Quote:
This is kind of tricky to comprehend (and describe too), so stay with me.


No chit. I've been trying to get you up to speed from the beginning. You continue to be a very stubborn student.

 Quote:
Your item A) above. Yes, when the oil pump is in relief mode “you have less than max flow” ... BUT really only less than the possible max the pump could have produced IF it wasn’t in relief mode.


Oh, really? So you've got a scenario where you're at an attenuated pressure and a reduced flow? ..and the pressure (drop) seen across the engine will be less than the (at the moment) FIXED system pressure, right? SP - Ep= ^across the filter, right?? Good ..now you're finally figuring it out!! \:\!


 Quote:
With higher pressure you get more flow.


You're at an attenuated pressure


You can't concede to the obvious. Let's abandon this whole conceptual thing and focus on ultra high volume stuff as it relates to taxing max flow capacity in filters.

Deckard: Bad joke. No really. Bad joke. Go home.


The basement always comes up to meet the ceiling. As that occurs there is no way to maintain a differential across the filter. You get reduced to (what might be described as something like) a valve constant. These relief event scenarios create the most frequent elevated PSID events BY FAR in ANY engine and therefore create the greatest potential for filter bypass events.

I'm getting tired....but I'm in conflict with the Black Knight in Monty Python's The Holy Grail.

You can call it a draw, if you want ..anytime.
Posted by: SuperBusa

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 03/27/09 07:34 PM

 Originally Posted By: Gary Allan
 Quote:
Your item A) above. Yes, when the oil pump is in relief mode “you have less than max flow” ... BUT really only less than the possible max the pump could have produced IF it wasn’t in relief mode.


Oh, really? So you've got a scenario where you're at an attenuated pressure and a reduced flow? ..and the pressure (drop) seen across the engine will be less than the (at the moment) FIXED system pressure, right? SP - Ep= ^across the filter, right?? Good ..now you're finally figuring it out!! \:\!


I don't think you quite followed me on that one ... probably my fault for not writing is clearly. Let elaborate ... this stuff really is tricky to get across; we BOTH know.

I think I tried to explain it in the last post above also, but here it is again. What I meant by the statement,

"Yes, when the oil pump is in relief mode “you have less than max flow” ... BUT really only less than the possible max the pump could have produced IF it wasn’t in relief mode."

is that the oil pump WILL put out more volume (beyond what it produces right at the 85 psi relief setting) only IF the PRM goes higher, and ONLY the excess output volume produced by the pump beyond the relief point is NOT going to flow through the filter/engine, but only back to the sump. So in essence, when in relief mode "you would have less than (the POSSIBLE) max flow" being produced by the pump actually going to the filter/engine. You are still putting the MAX amount of flow that the filter/engine flow path CAN TAKE at 85 psi, even though you are relieving the EXCESS volume that the oil pump is producing and sending back to the sump via the relief valve. See it?

 Originally Posted By: Gary Allan
I'm getting tired....but I'm in conflict with the Black Knight in Monty Python's The Holy Grail.

You can call it a draw, if you want ..anytime.


... yeah, this is one wild arsed discussion. I can go on for a good long time, and we probably are at the "draw" point. With time, some of this stuff will sink in and we can discuss later as it comes up in other threads. You were a difficult but honorable student, grasshopper.
Posted by: Gary Allan

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 03/27/09 08:04 PM

I agree, my young Padawan apprentice
Posted by: LoneRanger

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 03/27/09 08:15 PM

You guys are wearing my brain out.
Posted by: HondaRD

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 03/27/09 09:22 PM

 Originally Posted By: WagonBoss
After lurking around this site for several years and recently registering I'm compelled to make my first post. I have 2 Subies to maintain and found this a very interesting discussion, though much was far over my head.

I wrote to customer service at Hastings and this is the reply, though not technically helpful I found it to be an honest statement FWIW.

Recently there has been a bit of discussion on Subaru lube filters and the Subaru oil system on enthusiasts forums. The gist is that Subaru recently announced a new filter which the user community believes is produced by Honeywell (Fram) to Subaru specifications. Frankly, there is not much happiness in this new product. The discussion on the oil system indicates that Subaru uses a high volume oil pump and specifies a 23 PSID pressure relief valve.
I have two Subaru cars with the 4 cylinder 2.5 liter non-turbo engine. Both use a LF113 (or the longer LF240). My search through the various filter manufacturers' sites (Hastings/Baldwin, Wix, Fram, and Purolator) reveals that no filters, searched for my application, contains the 23 PSID pressure relief valve as specified. My primary concern is cold flow on startup as these are daily drivers - not a performance application. I use 5w-30 oil as recommended by the owners manual.
Should I be concerned about the difference between the 14 PSID spec on the LF113 and the factory spec of 23 PSID? Is there any technical reason the correct pressure relief is not available? Are there any plans to offer a filter with the correct specification?

Thanks in advance for your help. It is quite bewildering to have this great a variance in specifications.


REPLY:
Thank you for using Hastings Filters. I do not recommend using a filter with a 14-16 psi bypass valve in an application which calls for a filter with a 23 psi by-pass valve. We design our filters with a 3 psi maximum tolerance with regards to bypass valves. Therefore, I doubt that we would cross the new Subaru number to either the LF113 or the LF240. We do have a very similar filter with a 20 psi bypass valve. This is the LF491. If you have further questions, please feel free to contact me.
Cordially,

TRAVIS R. WINBERG
SUPERVISOR OF SERVICE ENGINEERING


I just followed your lead and sent a similar inquiry to WIX. I even went as far as asking them to consider increasing the bypass spring rate to meet the OEM specification if after they have confirmed the 8~11psi spec is indeed accurate. I may have to consider using Purolator if I don't use an OEM filter based on my limit research as they seem to be the closest to matching Subaru's spec: http://www.purolatorautofilters.net/en-us/resources/Popup/Pages/PartDetailPopup.aspx?partnum=PL14612
Posted by: rcy

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 03/27/09 09:31 PM

I sent an inquiry a few days ago regarding the Wix recommended filter not meeting the 23psi bypass the manufacturer wants. I asked them to recommend a Wix filter that would work.

Being in Canada, it looks like my question was redirected to "Affinia Group, Wix Division" I responded to the email by sending a link to this thread, and mentioning that the 23psi spec is from factory service manuals. At some point I'll get the Subaru part number for them as well, though really, that should be their job.
_______________________________
Here was the answer

Unfortunatly we are not aware of a 23 psi setting on the valve for that filter and we have a not had any problems or complaints about some one having an H6 and using this filter.
do you happen to have the oe part number so that we can check the valve settings and then we can go from there to find out if it could be a problem.

Thanks
*name edited*
AFFINIA Group Canada, WIX Division
(519) 622-4545 *277
*email edited*
Posted by: HondaRD

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 03/27/09 09:46 PM

Thanks rcy. Looks like you beat me to it :)

The OEM part number (as well as other mfg p/n's) is in this link. Since you already have dialog with WIX, would you mind forwarding this to them? When WIX responds to me, I'll do the same. I just hope we get lucky and get the attention of that one engineer that actually cares to research more into this and provide a technically sound reponse or convince WIX purchasing/planning dept to make a unique application for Subaru.

http://www.bescaredracing.com/sti/oil/filters/sti_oil_filters.xls


Posted by: SuperBusa

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 03/27/09 10:33 PM

 Originally Posted By: Gary Allan
I agree, my young Padawan apprentice


Luuuke ... I am your faaaather!

 Originally Posted By: LoneRanger
You guys are wearing my brain out.


Mine (or Gary's) isn't doing much better.
Posted by: SuperBusa

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 03/27/09 10:40 PM

 Originally Posted By: rcy
I sent an inquiry a few days ago regarding the Wix recommended filter not meeting the 23psi bypass the manufacturer wants. I asked them to recommend a Wix filter that would work.

Being in Canada, it looks like my question was redirected to "Affinia Group, Wix Division" I responded to the email by sending a link to this thread, and mentioning that the 23psi spec is from factory service manuals. At some point I'll get the Subaru part number for them as well, though really, that should be their job.
_______________________________
Here was the answer

Unfortunatly we are not aware of a 23 psi setting on the valve for that filter and we have a not had any problems or complaints about some one having an H6 and using this filter.
do you happen to have the oe part number so that we can check the valve settings and then we can go from there to find out if it could be a problem.

Thanks
*name edited*
AFFINIA Group Canada, WIX Division
(519) 622-4545 *277
*email edited*


See bold red text in your quote - my responses below.

My God! ... if you sent the link to this thread they are going to go completely insane trying to decyper it all!!

Also, saying that they "have not had any problems or complaints" doesn't mean much. As basically concluded in all this back and forth discussion here, if a filter with a much lower bypass setting than 23 psi is used, there is the possibility of a lot more bypass going on in the filter than if a filter with the 23 psi bypass was used. Will it cause the motor to blow up? I doubt it ... but IMO I'd RATHER have a filter that runs the oil through the filter element as much as possible, and not through the bypass.

Although, the one input in this thread about the turbo line screen getting debris on it kind of eluded that it could have been possibly caused by filter bypass allowing crud to get past the filter and into the engine's oiling system. Something to definitely consider as a possibility if the bypass valve is too weak for this Subaru application.
Posted by: rcy

Re: Subaru Oil Pump Specs as Relates to Filter Byp - 03/28/09 06:57 AM

 Originally Posted By: SuperBusa

My God! ... if you sent the link to this thread they are going to go completely insane trying to decyper it all!!



I thought they might learn something - or change professions.

I hope they don't do R&D by waiting for car owners to call in with problems or complaints on how the filters are working.
Posted by: LoneRanger

Re: Subaru Oil Pump Specs as Relates to Filter Byp - 03/28/09 09:32 AM

I sent an inquiry to Wix a couple weeks ago and didn't even get the courtesy of a reply other than the auto-reply bot saying the inquiry was recieved and I would get an answer in a few business days. Never got one. I don't think Wix cares that much, and probably won't be likely to adjust spring rating on the bypass valve to meet 23psi spec.

I'm active over on Subaruforester.org, and plan on sharing the results of this situation over there, once a firm conclusion can be arrived at. So far it seems to be: avoid after market filters, especially Wix, due to Wix's apparent low bypass psi (8 lbs) being only 1/3 of the OE spec (23.2psi). Wix filters are well made, but if the well madeness can still cause excessive bypass due to weak spring spec, it is going to mean your engine is getting unfiltered oil more often than Subaru intends.

Having said that, the ideal filter in this fantasy land of Wix adjusting spec for a super small market (Subaru is small market already, add to that us enthusiasts who actually care about the filter type) would be a 51356 (not typo-- 356 not 365) with its larger media area, same OE diameter, and a 23psi bypass valve instead of the 8 lb one.
Posted by: Gary Allan

Re: Subaru Oil Pump Specs as Relates to Filter Byp - 03/28/09 10:43 AM




Here's is what you would likely see on an oil pump of no exceptional volume output at start up where conditions were right for a relief event. Our same 85psi relief limit standing. Assume that visc/temp is appropriate to enable a relief event at startup. Filter has 10PSI rated relief valve.

Above:below

0:0
0-75:0-85
76:85
77:85
78:85
79:85
80:85
81:85
82:85
83:85
82:84
81:83
80:82
..and so on all the way down to normalized temps over majority of the range of engine operation. This may/will include just plain startup and 30 sec idle ..and driving away. The span between the numbers may drift a bit, but this is how they would basically lay out.

Now with a HV pump under the same conditions

0-75:0-85
76:85
77:85
78:85
79:85
80:85
81:85
82:85 (now start to drive)
82:85
83:88
85:90
85:92
85:95
87:97
90:100
and further along in the warm up event
85:95
83:93
83:91
83:89
83:87
83:85
81:83 still at normal engine speeds and warming up

after warm up (probably)

11:13
12:14
20:22
22:24
24:26 etc.etc ..etc. all the way up to where the flowpacity of the filter comes into play - which I've never seen in my testing over a broad span of engine rpms and temp/visc conditions.

The transitions are rather "dynamic" and no one state has any dwell time to speak of. I'm sure when you first start up, shear forces are substantial until the various layers become more fluid. That's how you can manage to actually increase volume while transitioning in relief and not exceed the relief threshold in many applications.
Posted by: SuperBusa

Re: Subaru Oil Pump Specs as Relates to Filter Byp - 03/28/09 07:07 PM

... not following your post above, so can't really make any constructive comments. "above:below" ???

All I can say is that the pump will go into relief any time the oil is too cold and/or the engine RPM high engough to make the pump TRY to push an amount of oil volume through the filter/engine flow path that will require more pressure than the relief vavle is set to.
Posted by: Gary Allan

Re: Subaru Oil Pump Specs as Relates to Filter Byp - 03/29/09 12:43 AM

Well, I surely appreciate your attempt at offering constructive content. Don't take failure too bad. You'll achieve it if you keep at it. All in due time, I guess. Don't rush success. We all should have gotten our 6 digit incomes while we still knew it all. Have faith in yourself, son!!

 Quote:
"above:below" ???




The above:below is simply on either side of the filter.

A rare view at the awe and mystery that reaches from the inner mind ..to the Outer Limits



 Quote:
All I can say is that the pump will go into relief any time the oil is too cold and/or the engine RPM high engough to make the pump TRY to push an amount of oil volume through the filter/engine flow path that will require more pressure than the relief vavle is set to.



This is true. Some setups run real close to the relief level at full operating temp with spec'd oil. Those will see the most PSID across the filter over the longest/most frequent span of time throughout their lives. Others, like my above example, peak pressure is almost a given every time the engine sees a cold start, regardless of ambient temp (like our subject Subaru here). Only the depth and duration of peak pressure events will vary.

Now that we know that this Bologna guy can't provide us with all the answers for things occurring in the magic can ..we need to reason a few things on our own here.
Posted by: Gary Allan

The basement always comes up to meet the ceiling - 03/29/09 11:56 AM

"The basement always comes up to meet the ceiling"

To further explain this statement, let's expand the realm of possibilities here.

Let's take our typical Subbie turbo owner who, while having the same 85lb relief HV oil pump, sees 100+ startup cold pressure. I'll venture to say that any cold start produces this starting pressure.

Here the ceiling is raised above the 85lb relief limit. This occurs since the volume that can fit through the relief port is less than Subaru felt sensible at start up visc to deprive the engine of in the maintenance of that 85lb spec.

This will maintain the differential across the filter.

85-23= 62

105-23= 82

The only difference at the exact same volume(s) is a matter of viscosity. Use a 0w-10 oil ..and this would not show the same pressures since the radically reduced visc would fit more easily through the engine and the relief port.


Here's an alternative way of viewing it. It requires a bit of massaging ..and is not offered for "the truth" of what necessarily occurs ..but if you eliminate a few roadblocks it can (perhaps) give you something else to relate to in how it appears.

important side note: I have never studied any of properties of Non-Newtonian vs. Newtonian physics as applied to fluids. I've asked questions of those who do and massaged what they've attempted to demonstrate into agreed to parallels that I can relate to/integrate. That's why I qualify everything with that it is not presented for "the truth" ..but merely to demonstrate the rationale/reasoning applied.

It's almost like a transition from a Non-Newtonian state to Newtonian (for all I know, Newtonian fluids DO transition from a Non-Newtonian "state" to a Newtonian state all the time ) ..except that this is usually demonstrated with a spinning spindle in a beaker. A Newtonian fluid will shear and form a bunch of circles that slow as they move to the outer edge of the beaker. Each layer producing friction to the next ..causing it to start moving. The faster the spindle turns, the mean velocity of the fluid increases.

Now take cake batter and do the same thing. You'll form a very small circle of motion ..and there will be no cascading movement toward the outer edge of the beaker.

Now you just replace the Non-Newtonian fluid in a beaker with a Newtonian fluid that represents enough mass to effectively simulate the same para-effect through a conduit. For a moment, consider it even the lightest fluid you can think of ..in any BIG conduit that you can think of ..but make it a mile long ..just to make 1gpm equating to several thousand pounds of fluid having to be moved at 1gpm between inlet and outlet. I think that you can figure that it's going to take a very long time for any pump to bring that mass up to speed. It may never occur and you'll be in a perpetual relief. Now just tone that down a good bit. You'll reduce the time lag ..or the "phase" relationship between pressure applied ..and volume moved.

Other views:

Think of a steam locomotive spinning its wheels at startup. A muscle car doing a burn out. Do they not parallel maximum applied pressure/force until the motion matches the applied power?

Let's just measure the time that a drag car has less than 100% traction. Isn't there a "differential" that evaporates after full traction is achieved? Now consider viscosity the mass of the car being pushed. Too much mass, longer burn out duration. The longer the "differential" will be maintained.

This is the same with torque converters ..except that they never completely hook up (without a mechanical clutch). You start off with a massive differential that evaporates as the mass gets accelerated.

Boat props ..same deal. It's this "out of phase" relationship that produces the PSID across your filter in most of the elevated PSID events that it will ever see.


Again, non of my examples are stated for "the truth". It's merely to offer other events that may allow you to get a grip on how relief events effect PSID and ..ultimately, filter bypass events.

There are other factors in the mix over the full scope of how a filter reacts in terms of pressure differential. One is loading. This effectively reduces the media ^2" and increases the impact of volume (at visc) through it. It WOULD simulate higher volumes up to the point where volume may be significant enough to make the filter a factor. In my experience with used filters, this still has limited impact ..but YMMV if you're dwelling in higher volume states with extended loading on the filter.
Posted by: SuperBusa

Re: Subaru Oil Pump Specs as Relates to Filter Byp - 03/29/09 02:04 PM

 Originally Posted By: Gary Allan
Well, I surely appreciate your attempt at offering constructive content. Don't take failure too bad. You'll achieve it if you keep at it. All in due time, I guess. Don't rush success. We all should have gotten our 6 digit incomes while we still knew it all. Have faith in yourself, son!!


Constructive content is only constructive if the receiver of the content opens his head and understands said content. It's hard to get "someone" with deep rooted erroneous thoughts to see the light of truth. ;\)


 Originally Posted By: Gary Allan
 Quote:
"above:below" ???


The above:below is simply on either side of the filter.

A rare view at the awe and mystery that reaches from the inner mind ..to the Outer Limits



Would have been nice to have those few extra key words to unlock the mysterious thoughts in a Gary post. I'm pretty cognizant of my world, but not quite to the ESP level just yet.

So what's the qualifying information for the gauge readings above? So now we know the cryptic "above:below" is the pressure across the filter. But at what exact operating conditions, as we both know the PSID is highly dependent on many factors. PSID of ~8 psi showing ... could it already be in filter bypass? ... hummm, could be.

 Originally Posted By: Gary Allan
 Quote:
All I can say is that the pump will go into relief any time the oil is too cold and/or the engine RPM high enough to make the pump TRY to push an amount of oil volume through the filter/engine flow path that will require more pressure than the relief valve is set to.


This is true.


When did you change your mind? ... this stuff must be slowly oozing in through subconscious osmosis.

 Originally Posted By: Gary Allan
Some setups run real close to the relief level at full operating temp with spec'd oil. Those will see the most PSID across the filter over the longest/most frequent span of time throughout their lives. Others, like my above example, peak pressure is almost a given every time the engine sees a cold start, regardless of ambient temp (like our subject Subaru here). Only the depth and duration of peak pressure events will vary.


When did you change your mind? ... A while back you were pretty sure that as the oil gets to operating temperature that the PSID across the filter "disappears", "evaporates", etc to basically zero. Just as I was saying all along, in a case like the Subaru in question, if the wrong filter is used with a bypass setting much lower than specified, then there will be many more and longer bypass events ... maybe even when the oil is at full temp with high RPM. This keeps coming back to what I've been saying since page 1 of this thread. Amazing.

Posted by: Gary Allan

Re: Subaru Oil Pump Specs as Relates to Filter Byp - 03/29/09 02:30 PM

 Originally Posted By: SuperBusa



 Originally Posted By: Gary Allan

[quote=Gary Allan]
 Quote:
All I can say is that the pump will go into relief any time the oil is too cold and/or the engine RPM high enough to make the pump TRY to push an amount of oil volume through the filter/engine flow path that will require more pressure than the relief valve is set to.


This is true.




 Originally Posted By: Gary Allan
Some setups run real close to the relief level at full operating temp with spec'd oil. Those will see the most PSID across the filter over the longest/most frequent span of time throughout their lives. Others, like my above example, peak pressure is almost a given every time the engine sees a cold start, regardless of ambient temp (like our subject Subaru here). Only the depth and duration of peak pressure events will vary.


When did you change your mind? ... A while back you were pretty sure that as the oil gets to operating temperature that the PSID across the filter "disappears", "evaporates", etc to basically zero. Just as I was saying all along, in a case like the Subaru in question, if the wrong filter is used with a bypass setting much lower than specified, then there will be many more and longer bypass events ... maybe even when the oil is at full temp with high RPM. This keeps coming back to what I've been saying since page 1 of this thread. Amazing.



I see no reference to operating temperature at all in your post that I agreed with. You simply stated, and I quote:

 Quote:
All I can say is that the pump will go into relief any time the oil is too cold and/or the engine RPM high enough to make the pump TRY to push an amount of oil volume through the filter/engine flow path that will require more pressure than the relief valve is set to.


You stated IF the oil was too cold (hence too thick) or the engine rpm too high, you'll be in relief. This was never disputed.

Your whole dispute with (just about) everything I've stated is just what causes PSID across the filter. I've successfully demonstrated conditions where PSID retreats in the midst of increased throughput of the filter specifically because of the relief event.

This has throw a monkey wrench in any absolute value to Ballony's immutable principles of flow dynamics ..or at least compressed them into irrelevancy in a SIZABLE chuck of our known reality
Posted by: SuperBusa

Re: Subaru Oil Pump Specs as Relates to Filter Byp - 03/29/09 03:00 PM

 Originally Posted By: Gary Allan

Here's is what you would likely see on an oil pump of no exceptional volume output at start up where conditions were right for a relief event. Our same 85psi relief limit standing. Assume that visc/temp is appropriate to enable a relief event at startup. Filter has 10PSI rated relief valve.

Above:below

0:0
0-75:0-85
76:85
77:85
78:85
79:85
80:85
81:85
82:85
83:85
82:84
81:83
80:82
..and so on all the way down to normalized temps over majority of the range of engine operation. This may/will include just plain startup and 30 sec idle ..and driving away. The span between the numbers may drift a bit, but this is how they would basically lay out.


Let's regress a bit here and readdress your so called "brilliant" analysis above. Since we now have established that your nomenclature "above:below" means the oil pressure "above" (before) and "below" (after) the filter ... how is it possible that the pressure is HIGHER after ("below") the filter than before the filter?

The most BASIC principle of fluid flow is that a PRESSURE DIFFERENCE makes fluid flow ... and fluid flows from a HIGH to LOW pressure. Bernoulli would flunk your arse over this big misunderstanding of basic fluid dynamics. No wonder I didn't get it.
Posted by: Gary Allan

Re: Subaru Oil Pump Specs as Relates to Filter Byp - 03/29/09 03:20 PM

Invert it for sensibility ..or you could use it for senseless distraction from/of what it's trying to communicate. Be my guest

When you go to the WIX site and see Beta 2/20 = 12/42 when you KNOW that the proper nomenclature is Beta12=2 and Beta42=20

..do you sit there and look and ponder that the WIX engineers are "wrong"??

I tend to wonder ... given your need to (apparently) re-educate me. I tend to think that you actually believe that I think otherwise ..which does bring YOUR cerebral capabilities into question

I gave you more credit than that ..but I may have been mistaken
Posted by: SuperBusa

Re: Subaru Oil Pump Specs as Relates to Filter Byp - 03/29/09 03:31 PM

 Originally Posted By: Gary Allan
Invert it for sensibility ..or you could use it for senseless distraction of what it's trying to communicate. Be my guest

When you go to the WIX site and see Beta 2/20 = 12/42 when you KNOW that the proper nomenclature is Beta12=2 and Beta42=20

..do you sit there and look

I tend to wonder given your need to (apparently) re-educate me. I tend to think that you actually belief that I think otherwise ..which does bring YOUR cerebral capabilities into question

I gave you more credit than that ..but I may have been mistaken


Dude ... I can't try to assume that you're stating everything backwards when you really mean it otherwise. No wonder these discussions are so screwed up and go in circles half the time. Can't even follow your reasoning on some of this stuff that makes it look like you don't understand what's going on. I still wonder. If you don't want misunderstanding, then relay the information correctly. I really don't see how you could blunder on something like that without actually thinking the physics were working as you stated. Backpedaling is easy to see. ;\)
Posted by: Gary Allan

Re: Subaru Oil Pump Specs as Relates to Filter Byp - 03/29/09 04:58 PM

 Quote:
Backpedaling is easy to see. ;\)



Yeah ..now how did you rationalize PSID evaporating when transitioning out of a relief event??? Perhaps not backpedaling ..more like tap dancing..


Posted by: SuperBusa

Re: Subaru Oil Pump Specs as Relates to Filter Byp - 03/29/09 05:03 PM

 Originally Posted By: Gary Allan

You stated IF the oil was too cold (hence too thick) or the engine rpm too high, you'll be in relief. This was never disputed.


Perfect \:\!

 Originally Posted By: Gary Allan
Your whole dispute with (just about) everything I've stated is just what causes PSID across the filter. I've successfully demonstrated conditions where PSID retreats in the midst of increased throughput of the filter specifically because of the relief event.


The only way the filter's PSID can "retreat" with "increased throughput of the filter" is if the oil viscosity goes WAY down (becomes super thin) in such a manner that it significantly over-rides the effects of the increased volume factor. Not disagreeing here, just stating that the conditions have to be right ... and usually are on most cars (without HV pumps) as you will always see the oil pressure do down significantly with thinner oil.

 Originally Posted By: Gary Allan
This has throw a monkey wrench in any absolute value to Ballony's immutable principles of flow dynamics ..or at least compressed them into irrelevancy in a SIZABLE chuck of our known reality


... seems like a nonsensical statement since you don't really have one clue on how Bernoulli's principles apply in these discussions.
Posted by: SuperBusa

Re: Subaru Oil Pump Specs as Relates to Filter Byp - 03/29/09 05:05 PM

 Originally Posted By: Gary Allan
 Quote:
Backpedaling is easy to see. ;\)



Yeah ..now how did you rationalize PSID evaporating when transitioning out of a relief event??? Perhaps not backpedaling ..more like tap dancing..



... I never claimed or "rationalized" that filter PSID "evaporated" at any point ... you did somewhere along the way in this discussion. You're really going in circles now.

The fact is, and I've said it all along, is that there will ALWAYS be some level of PSID across the filter if there is flow through it ... be it with or without the oil pump in relief mode. The pump being in relief mode or not doesn't change the reality that the PSID is directly related to the flow and viscosity of the oil going through the filter.
Posted by: Gary Allan

Re: Subaru Oil Pump Specs as Relates to Filter Byp - 03/29/09 05:31 PM

 Quote:
The only way the filter's PSID can "retreat" with "increased throughput of the filter" is if the oil viscosity goes WAY down (becomes super thin) in such a manner that it significantly over-rides the effects of the increased volume factor. Not disagreeing here, just stating that the conditions have to be right ... and usually are on most cars (without HV pumps) as you will always see the oil pressure do down significantly with thinner oil.


Knock-knock

Remember me?

85lb relief - filter in bypass @ 23lb pressure "drop" ..leaving 62lb pressure read at the engine??

What occurs when less flow is sent out the relief port? Hint: MORE flow goes to the engine.

So

..the filter can NO LONGER drop 23lb.

How can this be? MORE flow is traveling through the filter ..and ...lo a and behold..ONLY the engine side pressure increases. Amazing

As the relieved amount of oil approaches ZERO ..so will the PSID across the filter. It will be RADICALLY reduced to next to nothing.
Posted by: SuperBusa

Re: Subaru Oil Pump Specs as Relates to Filter Byp - 03/30/09 12:30 AM

 Originally Posted By: Gary Allan
 Quote:
The only way the filter's PSID can "retreat" with "increased throughput of the filter" is if the oil viscosity goes WAY down (becomes super thin) in such a manner that it significantly over-rides the effects of the increased volume factor. Not disagreeing here, just stating that the conditions have to be right ... and usually are on most cars (without HV pumps) as you will always see the oil pressure do down significantly with thinner oil.


Knock-knock

Remember me?

85lb relief - filter in bypass @ 23lb pressure "drop" ..leaving 62lb pressure read at the engine??


Some initial conditions, but actually not enough as it falls apart below.

 Originally Posted By: Gary Allan
What occurs when less flow is sent out the relief port? Hint: MORE flow goes to the engine.

So

..the filter can NO LONGER drop 23lb.


Now what's causing less flow through the relief port and causing the pump out of relief? Hotter oil, less RPM, both? All these factors will have a direct effect on what pump output volume will cause the relief valve to open or close, as well as effect the PSID across the filter and the engine's oil pressure reading.

If the pump goes out of relief and sends more volume to the filter/engine at the same time (while at the same RPM), then that can only happen if the oil is becoming hotter/thinner.

If the oil viscosity remains constant, then the only way the pump can go out of relief is to reduce through pump's RPM, which means it's output volume must also go down.


 Originally Posted By: Gary Allan
How can this be? MORE flow is traveling through the filter ..and ...lo a and behold..ONLY the engine side pressure increases. Amazing

As the relieved amount of oil approaches ZERO ..so will the PSID across the filter. It will be RADICALLY reduced to next to nothing.


If the oil's viscosity remains constant, then more engine oil pressure means more flow through the engine ... do you agree? If so, then you can't dispute that there is also more flow through the filter - you said so above. If there is more oil flow through the filter, then there is also a larger PSID across the filter - and if that PSID is above the bypass setting, then the filter will be in bypass mode.

It's the way it works ... "filter PSID will not approach zero" unless the engine oil pressure approaches zero. The filter's PSID will obviously be much lower than the engine's PSID ... not argurment there. But any time the engine oil pressure is high (high volume flow), then the filter's PSID is also relatively higher. Any time the engine's oil pressure is low (low volume flow), then so is the filter's relative PSID. They both go up and down in unison from 0 to their peak range, and the absolute values of the filter and engine PSID is dependant on the resistance ratio of the two in the serial flow path. Didn't we agree on that some time ago?

There is NO physical way that you can increase the engine's flow volume and pressure without also increasing the filter's flow volume and relative PSID. The filter's PSID can NOT go down to near zero while the engine's volume flow and pressure goes up. Sorry, ther is no way it can happen ... \:\(
Posted by: Gary Allan

Re: Subaru Oil Pump Specs as Relates to Filter Byp - 03/30/09 01:56 AM

 Quote:
Now what's causing less flow through the relief port and causing the pump out of relief? Hotter oil, less RPM, both? All these factors will have a direct effect on what pump output volume will cause the relief valve to open or close, as well as effect the PSID across the filter and the engine's oil pressure reading.


Dood!! The system pressure is fixed in this scenario ..the ENGINE PRESSURE CAME UP TO MEET IT All due to more flow.

How can a filter, that YOU HAVE ALLEGED (TIME AND TIME AND TIME AGAIN) AlWAYS HAS INCREASED PSID WITH AN INCREASE IN FLOW, DROP LESS PSID IN THE MIDST OF MORE FLOW???

According to you and your heralded Ballony, it can't. It's all the undeniable laws of physics that I've ignored



Riddle us that, batman

It's because the PSID IS NOT because of restriction to flow (OF THE FILTER), but the divergence of flow and the "apparent" effect that THAT condition creates as seen by the filter. Maximized pressure at reduced pressure over resistance derived flow.
Posted by: SuperBusa

Re: Subaru Oil Pump Specs as Relates to Filter Byp - 03/30/09 03:42 AM

 Originally Posted By: Gary Allan
 Quote:
Now what's causing less flow through the relief port and causing the pump out of relief? Hotter oil, less RPM, both? All these factors will have a direct effect on what pump output volume will cause the relief valve to open or close, as well as effect the PSID across the filter and the engine's oil pressure reading.


Dood!! The system pressure is fixed in this scenario ..the ENGINE PRESSURE CAME UP TO MEET IT All due to more flow.


You must have some good stuff there - how are you dreaming this stuff up? If the system (pump supply) pressure is fixed, then there will always be the same relative pressure drop split ratio across the filter and engine that will stay in proportion to the flow resistance ratio of the filter vs. engine flow resistance. It is IMPOSSIBLE for either the filter or engine to change it's relative pressure drop ratio because their flow resistance is FIXED, AND the SAME FLOW is going through both. That would be like saying the voltage drop across a resistor magically changes when the resistance value never changed with the same current going through it. Man, this really is the Twilight Zone.

 Originally Posted By: Gary Allan
How can a filter, that YOU HAVE ALLEGED (TIME AND TIME AND TIME AGAIN) AlWAYS HAS INCREASED PSID WITH AN INCREASE IN FLOW, DROP LESS PSID IN THE MIDST OF MORE FLOW???

According to you and your heralded Ballony, it can't. It's all the undeniable laws of physics that I've ignored

Riddle us that, batman


Huh? ... it CAN'T. I've never claimed that a filter will "drop less PSID in the midst of more flow" - but you have, so yeah, you ignored undeniable laws of fluid dynamics (more than once, I might add). In ANY FLOW PATH (with all variables constant except FLOW), the more flow you have the more PSID you produce. It's that SIMPLE ... even a caveman could do it.

 Originally Posted By: Gary Allan
It's because the PSID IS NOT because of restriction to flow (OF THE FILTER), but the divergence of flow and the "apparent" effect that THAT condition creates as seen by the filter. Maximized pressure at reduced pressure over resistance derived flow.


WTF? ... Sorry ... this really is out there - "divergence of flow" of what and to where? Dude, what flows through the filter flows through the engine. It can't be any other way. That last sentence seems like a double oxymoron ... wild stuff.

PSID is ALWAYS due to flow going through a restriction. It is just plain blatantly WRONG to say a pressure drop across a filter (or any other flow restriction) is not caused by the fluid and it's properties flowing through it. You really need to do some basic fluid dynamics home schooling lessons ... Bernoulli is waiting.
Posted by: Gary Allan

Re: Subaru Oil Pump Specs as Relates to Filter Byp - 03/30/09 07:14 AM

Dood...

Drop the crack pipe.

85lb -23lb = 62lb

What happens when the engine passes more fluid?? That is, the amount of relieved flow is reduced?

85lb- <23lb PSID= >62 PSI

How complicated is the math??

70 IQ required.

More flow to the engine resulted in lower filter PSID and higher pressure engine to atmosphere.

Now you're into either narcissistic desperation ..or full fledged trollhood.
Posted by: rcy

Re: Subaru Oil Pump Specs as Relates to Filter Byp - 03/30/09 02:16 PM

Wow. I have to say I'm impressed with Wix Canada. I received this email today from them after answering their email regarding their answer to my original email. In my second email, I mentioned that I would try to get a part # for them and added that I suspect the filter the dealer sells is a Honeywell/Fram.
________________
Hi Richard, i just wanted to make sure you know i haven't forgot you but i was hoping to get that part # so that we could do a little research of our own,

We are also in Canada and most of the part numbers in north america are the same or able to be interchanged.

*edit* (to protect the innocent - a comment about another oil filter company was here)

thanks
*edit*
AFFINIA Group Canada, WIX Division
(519) 622-4545
*edit*
_______________________

So anyway, I called the dealer and sent the part #. We'll see what happens.

 Originally Posted By: rcy
I sent an inquiry a few days ago regarding the Wix recommended filter not meeting the 23psi bypass the manufacturer wants. I asked them to recommend a Wix filter that would work.

Being in Canada, it looks like my question was redirected to "Affinia Group, Wix Division" I responded to the email by sending a link to this thread, and mentioning that the 23psi spec is from factory service manuals. At some point I'll get the Subaru part number for them as well, though really, that should be their job.
_______________________________
Here was the answer

Unfortunatly we are not aware of a 23 psi setting on the valve for that filter and we have a not had any problems or complaints about some one having an H6 and using this filter.
do you happen to have the oe part number so that we can check the valve settings and then we can go from there to find out if it could be a problem.

Thanks
*name edited*
AFFINIA Group Canada, WIX Division
(519) 622-4545 *277
*email edited*
Posted by: SuperBusa

Re: Subaru Oil Pump Specs as Relates to Filter Byp - 03/30/09 04:30 PM

 Originally Posted By: Gary Allan
Dood...

Drop the crack pipe.

85lb -23lb = 62lb

What happens when the engine passes more fluid?? That is, the amount of relieved flow is reduced?

85lb- <23lb PSID= >62 PSI

How complicated is the math??

70 IQ required.

More flow to the engine resulted in lower filter PSID and higher pressure engine to atmosphere.

Now you're into either narcissistic desperation ..or full fledged trollhood.


Ummm ... are you actually aware that the oil pump’s relief valve is BEFORE the oil filter? Is this the simple unknown fact by you that is the cause of all your misinformation derailment in these discussions? I’m really trying to figure out why you don’t understand the physics here.

Again ... please listen to this fact. The engine CAN NOT PASS MORE FLUID WITHOUT THE OIL FILTER ALSO PASSING THAT SAME EXACT AMOUNT OF MORE FLUID. What goes through the engine goes through the filter ... what goes through the filter goes through the engine. Period - EVEN IN PUMP BYPASS MODE. It doesn’t work any other way. How hard is that to understand?

"85lb - 23lb = 62lb" and then “85lb - <23lb PSID= >62 PSI” ... can NOT happen. Listen carefully ...it can NOT happen because if the filter’s PSID goes down so will the engine’s oil pressure by a relative factor associated by its relative resistance to flow. The engine oil pressure can NEVER go up while the oil filter PSID goes down –- or vica versa.

If the engine oil pressure goes up, so does the filter PSID by some corresponding amount ... if the engine oil pressure goes down, so does the filter PSID by some corresponding amount. The engine’s oil pressure and filter’s PSID go up and down IN UNISION because the SAME EXACT FLOW VOLUME (at the same exact viscosity) is going through both – ALWAYS!

When an oil pump goes into relief mode, the same EXACT flow volume is still going through both the filter and engine – and will be the MAX flow volume the pump can put through the system at that relief setting and oil viscosity.

Do you agree with the oil system flow path shown below? If you do, then it really shouldn’t be hard to visualize the flow physics of the SYSTEM, and that every drop of oil that flows through the oil filter must also flow through the engine ... even in pump relief mode.

1) Oil enters the pickup screen/tube in sump.
2) Oil enters the oil pump.
3) Oil goes flows past the oil pump’s relief valve – flow can split here if the pump’s output pressure exceeds the relief valve’s pressure setting. What is not sent back to the sump goes to the oil filter.
4) Oil goes through the oil filter – oil can bypass the filter element if the filter’s PSID is greater than the filter’s bypass valve pressure setting.
5) Oil goes past the engine’s oil pressure gauge. The oil pressure gauge is really a direct indication of the oil volume/viscosity combo flowing into the engine.
6) Oil flows through all the various flow paths to lubricate parts inside the engine, and then flows back to the sump at various exit points in the engine.

HINT – this may take WAY more than a 70 ID to grasp.
Posted by: SuperBusa

Re: Subaru Oil Pump Specs as Relates to Filter Byp - 03/30/09 04:47 PM

 Originally Posted By: rcy
Wow. I have to say I'm impressed with Wix Canada. I received this email today from them after answering their email regarding their answer to my original email. In my second email, I mentioned that I would try to get a part # for them and added that I suspect the filter the dealer sells is a Honeywell/Fram.
________________
Hi Richard, i just wanted to make sure you know i haven't forgot you but i was hoping to get that part # so that we could do a little research of our own,

We are also in Canada and most of the part numbers in north america are the same or able to be interchanged.



Well, it looks like you got them thinking about this at least. It will be interesting to see if they have or will supply a filter with the appropriate bypass pressure setting for the Subarus in question.

Anything would be better to hear in this tread besides the brutal horse beating on oil system physics theory.
Posted by: Gary Allan

Re: Subaru Oil Pump Specs as Relates to Filter Byp - 03/30/09 05:01 PM

 Quote:
are you actually aware that the oil pump’s relief valve is BEFORE the oil filter?


Yes. Well aware.

 Quote:
The engine CAN NOT PASS MORE FLUID WITHOUT THE OIL FILTER ALSO PASSING THAT SAME EXACT AMOUNT OF MORE FLUID.


Yes. Painfully apparent.

 Quote:
What goes through the engine goes through the filter ... what goes through the filter goes through the engine. Period - EVEN IN PUMP BYPASS MODE. It doesn’t work any other way. How hard is that to understand?


Yep ..o wise sage of future struggle.


 Quote:
"85lb - 23lb = 62lb" and then “85lb - <23lb PSID= >62 PSI” ... can NOT happen.



Oh, really? I'm sorry ..but here's where you're very mistaken ..but let us allow you to go FULL DEPTH into your misconceptions to, perhaps, have you abandon your dogma as truth ..at least in all circumstances.

 Quote:
Listen carefully ...it can NOT happen because if the filter’s PSID goes down so will the engine’s oil pressure by a relative factor associated by its relative resistance to flow. The engine oil pressure can NEVER go up while the oil filter PSID goes down –- or vica versa.


ANNNK!!!! Wrong.

Relative resistance is ONLY apparent when the circuit is a series circuit. You've not figured the variable resistor that is in parallel, the relief. Once closed, the filter is next to nothing in apparent resistance. When open, the filter, and the relief are variable (apparent) resistors. The combined pressure drop across the filter and the engine is what the relief drops (supply - in this case, 85lb). Now in that subset, the engine will drop what it does based on the flow through it. The filter MUST SEE the difference. It sees supply pressure above it ..and the pressure drop of the engine below it. The difference is the PSID. As the throughput of the oil biases more to the engine, the supply will remain 85lb and the engine will drop more (this is where my term "develop" works much better). The PSID will start to erode.

When more flow passes through the filter to the engine, the drop across the engine MUST INCREASE. Since we're slammed up against the supply (again, 85lb) the filter will decrease its "apparent" resistance to satisfy the equation.

This is the big thing you totally miss since you've never seen it with your own eyes. You're IGNORANT of this interrelationship between relief flow and apparent PSID across the filter. Without relief flow, there is virtually NO PSID across the filter.

Go test it for yourself and you'll see.

I HAVE. You don't know what you're talking about under these conditions.



Posted by: SuperBusa

Re: Subaru Oil Pump Specs as Relates to Filter Byp - 03/30/09 08:02 PM

 Originally Posted By: Gary Allan
 Quote:
"85lb - 23lb = 62lb" and then “85lb - <23lb PSID= >62 PSI” ... can NOT happen.


Oh, really? I'm sorry ..but here's where you're very mistaken ..but let us allow you to go FULL DEPTH into your misconceptions to, perhaps, have you abandon your dogma as truth ..at least in all circumstances.


Don’t be so certain ... too much confidence can be seriously embarrassing at times. I really wish someone else with some fluid dynamics education would step into this discussion for a 3rd party viewpoint, as this round ‘n round bullsheet if getting very old at this point. I’ve tried to describe what’s going on in every way imaginable to no avail.

 Originally Posted By: Gary Allan

 Quote:
Listen carefully ...it can NOT happen because if the filter’s PSID goes down so will the engine’s oil pressure by a relative factor associated by its relative resistance to flow. The engine oil pressure can NEVER go up while the oil filter PSID goes down –- or vica versa.


ANNNK!!!! Wrong.

Relative resistance is ONLY apparent when the circuit is a series circuit. You've not figured the variable resistor that is in parallel, the relief.


You’re missing something key here. The filter + engine is ALWAYS a series circuit regardless if the pump is in relief mode or not, so there is ALWAYS AN APPARENT RELATIVE RESISTANCE for both the filter and engine at all times ... you just said so above. Look at what’s going on just downstream of the pressure relief valve ... it’s ALWAYS a serial flow circuit with the same exact oil flow volume going through both the filter and engine at any point in time.

The filter/engine circuit really could care less what the relief valve is doing. The only thing the oil pump relief valve is designed for is to ensure that a pre-determined maximum oil pressure does not get applied to the filter/engine (series) circuit. It simply shunts a portion of the oil flow to the sump to control applied pressure to the filter/engine circuit. The flow volume that goes through the filer/engine circuit (regardless if the pump is in relief or not) is solely determined by the oil pressure, oil viscosity AND the relative resistance factor of BOTH the filter and engine.

Assume the oil viscosity is always constant, and that the engine RPM is changed slowly from idle to 7000 RPM redline. Obviously, the pump’s output pressure is caused by the near linear volume output due engine RPM – a trait of a positive displacement pump. The oil pump under these conditions goes into its 85 psi relief mode at 5500 RPM. Assume a pretty restrictive oil filter is being used. This would then be the general trend of what’s going on in the oil system with these conditions.

Key to number layout:
RPM – Pump Out P (psi) – Filter PSID (psi) – Engine Oil P (psi)

1000 – 40 – 2 - 38
2000 – 50 – 4 - 46
3000 – 60 – 6 - 54
4000 – 70 – 8 - 62
5000 – 80 – 10 – 70
5500 – 85 – 11 - 74
6000 – 85 – 11 - 74
6500 – 85 – 11 - 74
7000 – 85 – 11 – 74

As you can see ... BOTH the filter’s PSID and engine’s oil pressure went up in unison based on their relative resistance to the oil flow. Once the pump’s relief valve is hit at 5500 PRM, then the system is stable from that point and up since the flow volume actually going to the filter/engine serial circuit is constant when in pump relief. Maybe that is that part you are hosed up on? Gary – once the pump hits relief mode, the flow volume is constant going into the filter/engine (assuming the relief valve is designed right). This is important to realize.

Note that if this particular oil filter had a bypass valve set to 8 psi, that it would have been in bypass mode around 4000 RPM.

 Originally Posted By: Gary Allan
Once closed, the filter is next to nothing in apparent resistance. When open, the filter, and the relief are variable (apparent) resistors.


Nope ... when the pump’s relief valve is closed it doesn’t mean there is not significant flow still going to the series filter/engine flow path ... the example above shows that. Again, BOTH must receive the SAME flow volume, so if there is high flow in the engine, there is also the same high flow in the filter. Flow volume, viscosity and relative flow resistance of a device all determine the pressure drop (PSID) across that device. If the flow goes down (with constant viscosity), then the filter’s PSID AND the engine’s oil pressure will both go down accordingly.

 Originally Posted By: Gary Allan
The combined pressure drop across the filter and the engine is what the relief drops (supply - in this case, 85lb). Now in that subset, the engine will drop what it does based on the flow through it. The filter MUST SEE the difference. It sees supply pressure above it ..and the pressure drop of the engine below it. The difference is the PSID.


See above example.

 Originally Posted By: Gary Allan
As the throughput of the oil biases more to the engine, the supply will remain 85lb and the engine will drop more (this is where my term "develop" works much better). The PSID will start to erode.


How can “the throughput of the oil biases more to the engine” happen if the SAME FLOW is always going through both the filter and engine in the series flow path?

 Originally Posted By: Gary Allan
When more flow passes through the filter to the engine, the drop across the engine MUST INCREASE. Since we're slammed up against the supply (again, 85lb) the filter will decrease its "apparent" resistance to satisfy the equation.


See example above. When the supply pressure is slammed up against the 85 psi relief setting, then the filter AND engine will show their largest pressure drops. The filter can not decrease it’s PSID at max flow conditions. The pressure drops are CONSTANT from the point of pressure relief and above (5500 PRM and above in the example). That’s how it really works.

 Originally Posted By: Gary Allan
This is the big thing you totally miss since you've never seen it with your own eyes. You're IGNORANT of this interrelationship between relief flow and apparent PSID across the filter. Without relief flow, there is virtually NO PSID across the filter.

Go test it for yourself and you'll see.

I HAVE. You don't know what you're talking about under these conditions.


Your statement above in red = not true. At one time, certain people thought the Sun revolved around the Earth because that’s what their senses of the conditions “told them”. I’m thinking the same phenomenon has occurred in your testing, and has led you to construct some invalid flow models in your head. It can happen to anyone I guess if they don’t have all the facts at hand.
Posted by: Gary Allan

Re: Subaru Oil Pump Specs as Relates to Filter Byp - 03/30/09 08:24 PM

I'll skip over your self created stuff. It may indeed exist at some point in some situation. Filter resistance is negligible for the vast majority of throughput. It would obviously be a factor at mega volumes.

 Quote:
How can “the throughput of the oil biases more to the engine” happen if the SAME FLOW is always going through both the filter and engine in the series flow path?


Dood. You've got 100% flow out of a pump. A percentage of that ISN'T GOING THROUGH THE FILTER OR ENGINE.

IT EXISTS, AT WHATEVER FLOW RATE THAT IS, AT OR ABOVE THE RELIEF LIMIT (AT the limit so that this "MAY" get through to you).

Let's say that 50% of the 100% is shunted/relieved (for example)

That means that 80% of the flow is going through the filter and the engine.

So, 50% of the flow with 100% of the pressure applied. What pressure is the engine going to see?

A:50% of what it would if it was receiving 100% of the flow. No denying that ...DOOD.

So, if you take our 85lb max ..and take 50% of that, we would have 42.5 across the engine ..and 42.5 across the filter.

BUT WAIT, we have a filter bypass that doesn't allow this to occur. It's maxed @ 23lb..so the engine MUST SEE

85-23=62 regardless of what the filter would offer in resistance if no bypass valve existed.

That's why it is there.

As the flow is more and more biased to the filter/engine, that pressure differential MUST retreat.

If you can't admit that MORE FLOW through the engine will drop more pressure ..then you've just spit in Ballony's eye.

85
Posted by: Gary Allan

Re: Subaru Oil Pump Specs as Relates to Filter Byp - 03/30/09 10:51 PM

The main problem is that you view the filter as a static resistance. If you push enough volume through it, then, sure, it will show some increased PSID (non-relief).

This is NOTHING compared to what a filter can present in terms of resistance to flow when you don't have the downstream (back pressure) as a choke. This back pressure is much more in a non-relief state.

A filter in a normal pressure applied (non-positive displacement) scenario is a virtual brick wall to flow.

This is why it's so critical for you to understand the dynamics of what occur when the oil pump goes into relief. It "unmasks" the restrictive properties of the media that are virtually transparent when you're out of relief. Out of relief, the engine trumps it BIG TIME.


..and I've tried every way that I can think of to get your light bulb to glow too, pal. You've not gleaned one insight into the physical events as they occur ..and are redundantly reciting properties that don't apply in this situation.


Again, where are your images of above and below filter readings? Where are your testing devices ..your practical applications of your theories? They don't exist if I read my SuperBusa's right

Posted by: Gary Allan

Re: Subaru Oil Pump Specs as Relates to Filter Byp - 03/31/09 09:23 AM

Okay ..let's give it another try here.

Let's say we EXCEED the relief level by increasing the engine speed.

Now YOU ASSERT that the filter MUST conform to Ballony's Laws.

We have our normal 85lb relief limit ..but the visc is WAY TOO HIGH for the relief port to handle the volume that the pump puts out ..and maintain 85lb. This happens in the Euro-Alloy ..it happens with the Subbies with gauges.

DO YOU DOUBT THIS ..AND REQUIRE MULTIPLE TESTIMONIALS, OR WILL YOU ADMIT THIS IS A "TRUTH" in SOME circumstances???


So:

Let's just say that it can maintain 85lb AT IDLE. Now the driver applies the gas pedal and the volume INCREASES. According to you and Ballony, the PSID MUST INCREASE.

..but it can't ..the bypass valve prevents this alleged immutable law of fluid dynamics from taking place.

In the case of our Subbie owners, it means that we now have:

100psi - 23lb(filter)= 77psi across the engine.

Gee, the filter is (relatively) "compressed" in PSID. That is, it's % of total pressure system drop ACROSS THE FILTER is REDUCED.

It now represents 23% of total system pressure drop ..instead of 27% .... AMAZING

How can this be according to you and your beloved Ballony?

As we advance the volume (and pressure) the floor continues to shave the difference between it and the ceiling ..and the PSID across the filter REMAINS THE SAME.

Now slide that view back and forth (85lb in relief @ 23PSID and 100psi @ 23PSID) watching the "apparent" effects and what causes them.

Now you massage your view to relief events that DO NOT MAINTAIN THE 23PSID state ..YET STILL HAVE AN ATTENUATED PRESSURE LEVEL ..and what do you get?

You get PSID across the filter (when in relief) being a byproduct of total flow minus relief flow ..as seen by the engine in isolation. The engine has no reactive component to it. It's a linear resistive element (for the most part - I'm sure someone could pick some nits out of their butt). I think you'll have a very hard time reasoning your way around that. It drops whatever it does based on the flow it sees. The filter, however, sees supply pressure. The difference is the PSID.

Your model with massive rpms and volumes is a way "also ran" aspect to it in 99&44/100 % of the rolling population on the planet..and the figures are not accurate in observations that I've performed ..and you have not.
Posted by: SuperBusa

Re: Subaru Oil Pump Specs as Relates to Filter Byp - 03/31/09 07:35 PM

I've only responded to the first of your three latest posts ... dude, you're goin' nuts here. If I find time, I'll address some of your last two posts. This is getting really time consuming, and frankly my time could be spent on better things.

 Originally Posted By: Gary Allan
 Quote:
How can “the throughput of the oil biases more to the engine” happen if the SAME FLOW is always going through both the filter and engine in the series flow path?


Dood. You've got 100% flow out of a pump. A percentage of that ISN'T GOING THROUGH THE FILTER OR ENGINE.

IT EXISTS, AT WHATEVER FLOW RATE THAT IS, AT OR ABOVE THE RELIEF LIMIT (AT the limit so that this "MAY" get through to you).


Yeah, so? ... I’ve said that many times in this thread. Everything that comes out of the pump either goes through the filter/engine circuit OR is split between the filter/engine circuit and the relief valve that spits flow back to the sump. No news here.

 Originally Posted By: Gary Allan
Let's say that 50% of the 100% is shunted/relieved (for example)

That means that 80% of the flow is going through the filter and the engine.


Whoa ... if 50% of the 100% pump volume output is shunted/relieved, then 50% of the flow is going to through the filter and the engine – NOT 80%. Probably a typo – no one is that bad at math.

 Originally Posted By: Gary Allan
So, 50% of the flow with 100% of the pressure applied. What pressure is the engine going to see?

A:50% of what it would if it was receiving 100% of the flow. No denying that ...DOOD.


Not necessarily true. The pressure the engine is going to see will be equal to 85 psi (supply pressure in relief mode) minus whatever the filter PSID will be with this 50% flow volume flowing through it. Again, the PSID across any flow device (restriction) will be determined by the flow volume, oil viscosity and flow resistance of the device. In any pump relief mode case (at any given point in time - meaning all conditions being constant), the flow volume going to the filter/engine is the max possible since the pump is holding the supply pressure at a constant 85 psi – more on that later.

So the actual pressure the engine sees in this case will be totally dependant on what filter PSID is generated by this “50% flow” volume. The only way the filter/engine could receive 100% of the pump flow would be if the pump was out of relief mode just below the relief pressure (ie, 84.9999 psi). The filter/engine can also receive 100% of the pump flow if the supply pressure is well below relief pressure ... BUT, in order for that to happen it would mean that the pump RPM was less, which produces less volume and a pressure below the relief valve setting.

The bottom line is that the pump can not push any more volume through the filter/engine circuit than the 85 psi will allow. Any excess volume beyond that will go out the relief valve and back to the sump. As always, assume viscosity is constant in these examples.

On a side note ... the actual relationship between pressure and fluid flow volume rate through a fixed resistance is not a linear function ... but for simplicity sake we can assume that it is in your example. Flow volume rate is actually proportional to the square root of pressure. Guess who says so – your buddy, Bernoulli.

 Originally Posted By: Gary Allan
So, if you take our 85lb max ..and take 50% of that, we would have 42.5 across the engine ..and 42.5 across the filter.


The engine could only see 50% of the 85 psi pressure IF the filter had exactly the same resistance to flow as the engine did, and caused half of the 85 psi supply pressure to drop across the filter (a 42.5 PSID). That’s not the case ... do you really think a filter will have the same flow resistance as the engine. Remember your 2 ft dia pipe vs. 1/2 “ dia pipe analogy? You’ve said may times that the engine is magnitudes more restrictive than the filter ... so why are you now saying they are the same. That PSID breakdown is NOT possible unless the filter was just as resistive to flow as the engine was in this serial flow circuit.

The filter will have a PSID across it that is totally dependant on flow volume, oil viscosity and filter resistance – call it a realistic 5 psi pressure drop in this case since we both know a filter is MUCH less restrictive than the engine. That means in this case that the engine’s inlet pressure (ie, oil pressure gauge) would be reading 80 psi (85 psi – 5 psi).

The amount of pressure drop across the filter and engine will always be split in proportion to the resistance ratio of each in the flow circuit – the sum will always add up to the supply pressure (of course). Also (and this is KEY), the amount of volume that the pump sends to the filter/engine circuit while in relief mode is also dependant on the oil viscosity and filter/engine flow path resistance. The engine’s resistance is fixed, so if you put in a more restrictive filter on the car, then there will be less volume going to the filter/engine while in pump relief mode - 85 psi supply will push less volume as the flow path resistance goes up, and the rest of the pump volume output goes back to the sump. This is exactly why some guys see a lower oil pressure when using a more restrictive oil filter. Of course, cold start/run scenarios is where this will show up the most.

 Originally Posted By: Gary Allan
BUT WAIT, we have a filter bypass that doesn't allow this to occur. It's maxed @ 23lb..so the engine MUST SEE

85-23=62 regardless of what the filter would offer in resistance if no bypass valve existed.

That's why it is there.


Yeah, I agree that the filter’s bypass valve will indeed limit the filter’s max PSID, and in turn “ensure” enough oil volume gets to the engine. That maybe one aspect of its function, but I really do not think the main purpose of the filter bypass valve is there to regulate how much oil pressure/flow the engine sees. The filter bypass valve setting is really there to ensure that the filter will only go into bypass mode when it’s supposed to. If the bypass setting is set TOO LOW for a particular application, then it will be bypassing unfiltered oil much too often and longer as compared to a filter with the right bypass setting. The “ultimate goal” IMO, is to have an oil filter that never goes into bypass mode unless it’s getting too loaded up with contaminates to the point where the filter is choking engine pressure to the danger point, or the filter element can’t take the PSID (which ever occurs first).

 Originally Posted By: Gary Allan
As the flow is more and more biased to the filter/engine, that pressure differential MUST retreat.


Major error here. There is no such thing as ... “the flow is more and more biased to the filter/engine” resulting in a “retreat” (decrease) in the pressure differential between the filter and engine. That is what you mean, I assume?

That is because when the oil pump is in relief mode - and assuming the relief valve works perfectly to keep the supply pressure right at 85 psi – then the flow volume going to the filter/engine is going to be constant (with constant oil viscosity). I tried to point this out earlier, but you don’t seem to read/comprehend my stuff. Any time the oil pump is in relief mode the oil volume going to the filter/engine is constant, and will be the max possible for the system conditions at that exact point in time. As the pump goes out of relief mode - which can only happen if the engine RPM has decreased if all conditions are constant – then the pump output volume to decrease as well, and less volume will be going to the filter/engine.

When the pump hits the relief pressure, the flow to the filter/engine stays at a max constant while the flow going back into the pump increases as the pump’s output increases with the supply pressure at 85 psi.

[quote=Gary Allan]If you can't admit that MORE FLOW through the engine will drop more pressure ..then you've just spit in Ballony's eye.[quote]

The only thing that is pure B-O-L-O-N-E-Y around here is some of your thoughts on how an oiling system like this really works – and also your writing skills at times..
Posted by: Gary Allan

Re: Subaru Oil Pump Specs as Relates to Filter Byp - 03/31/09 07:48 PM

 Quote:
This is getting really time consuming, and frankly my time could be spent on better things.


Translation: Surrender is near.


Dood, all you have to do is rationalize my bona fide witnessed results and show me an alternative paradigm.

You can't do that.

So you suggest "disbelief" of what I assure you occurs. You, effectively, are calling me a liar. I've told you what occurs, and you can't figure out how.

Go get yourself a set of gauges and perform the tests yourself.
Posted by: SuperBusa

Re: Subaru Oil Pump Specs as Relates to Filter Byp - 03/31/09 08:01 PM

 Originally Posted By: Gary Allan
 Quote:
This is getting really time consuming, and frankly my time could be spent on better things.


Translation: Surrender is near.

Dood, all you have to do is rationalize my bona fide witnessed results and show me an alternative paradigm.

You can't do that.

So you suggest "disbelief" of what I assure you occurs. You, effectively, are calling me a liar. I've told you what occurs, and you can't figure out how.

Go get yourself a set of gauges and perform the tests yourself.


Like I said, tests can be setup wrong, ran wrong, and interpreted wrong. That doesn't make you a liar, but a bad tester. ;\)

Surrender is not near ... but you have to admit that this is getting pretty frickin' ridiculous. Is that all it is to you ... who's going to "surrender" first? I've battled with a few like you for nearly a year on something that even others on the board chimed in on to verify my inputs, and the guy I was dealing with STILL didn't believe the truth.

I understand most of your inputs, but there are some things that you think happen that just can't.

Also ... you didn't even read my last post in detail because you responded as soon as you read the first few sentences. Read my responses carefully, and you'll (might) see things differently ... especially on what's going on during pump relief.

OK ... let's start a new direction of discussion in this. I want you to post up exactly how your test setup was, and all the exact details of the test run and the results you saw. I have over 20 years experence in the test world ... let's see your [censored].
Posted by: SuperBusa

Re: Subaru Oil Pump Specs as Relates to Filter Byp - 03/31/09 08:38 PM

 Originally Posted By: Gary Allan
The main problem is that you view the filter as a static resistance. If you push enough volume through it, then, sure, it will show some increased PSID (non-relief).


There is always some level of PSID in a filter if there is flow through it. The filter PSID can not exceed it's bypass valve setting (assuming the bypass valve can bypass 100% effectively). Yeah, so ... I've stated this MANY times.

 Originally Posted By: Gary Allan
This is NOTHING compared to what a filter can present in terms of resistance to flow when you don't have the downstream (back pressure) as a choke. This back pressure is much more in a non-relief state.


In my discussions, I'm always assuming there is total flow throughout the system, so there will indeed be "backpressure" on the filter. But it still does not retract from the fact that if there is flow through the filter there is an associated PSID.

 Originally Posted By: Gary Allan
A filter in a normal pressure applied (non-positive displacement) scenario is a virtual brick wall to flow.


Give me an exact example of that scenario.

 Originally Posted By: Gary Allan
This is why it's so critical for you to understand the dynamics of what occur when the oil pump goes into relief. It "unmasks" the restrictive properties of the media that are virtually transparent when you're out of relief. Out of relief, the engine trumps it BIG TIME.


Like I've said before, this is how I see it ...

When the oil pump goes into relief mode (at say 85 psi), it is sending the maximum amount of oil volume possible to the filter/engine at that instant in time based on the total flow resistance of the filter/engine flow path.

The pump will force a constant flow volume through the filter/engine circuit with an 85 psi supply pressure, no matter how fast you turn the oil pump after it hits relief pressure (assuming the relief valve is 100% effective). That filter/engine flow volume will be the max possible at that instant in time, and you will see the max filter PSID and max engine pressure at this same point in time.

Any flow volume out of pump relief mode will mean less filter PSID and also less engine oil pressure because the actual volume going through the filter/engine flow path is now less than it was when the pump was in relief mode at 85 psi. Don't you see that?
Posted by: Gary Allan

Re: Subaru Oil Pump Specs as Relates to Filter Byp - 03/31/09 09:38 PM

I stop reading where you go astray. It's that simple. You "force" stuff and merely "work it through" without supporting "here, see?"

You fail to "demonstrate" any sound methodical rationale to support your "stuff". Just stating something is so and expecting it to be that way.

You've focused on just dismissing my assertions and not truly disproving them.

Again, I can't argue in Ballony's (spell it as you please) world. I told you that from the beginning. What's clear is that you can't work outside of your preconceived box and effectively explain things that are occurring in the real world. While I'm sure Bulloni is right, you can't integrate that there are situations where you've applied universal constants in the wrong proportions.

Concession is conspicuously absent where it should be painfully apparent.

..but you had to be the new sheriff in town ..so


 Quote:
I want you to post up exactly how your test setup was, and all the exact details of the test run and the results you saw. I have over 20 years experence in the test world ... let's see your sh*t.


At first, in an attempt to keep you honest, I was going to say "Oh ..no, pal. You first describe acceptable testing procedures and I'll see if mine conform to them" ..since I predict that you'll just pull more stuff out of your behind to discount the test platform.

Now if you find flaw with this, then you'll bury yourself for all time in trolldom


I used a Permacool sandwich adapter with the poppet relief welded shut. I then routed it to a dual Permacool filter mount where I used a block adapter on one of the filter mounts and a filter on the other. Hence pressure was read above and below the filter. This was routed to the two pressure gauges that you have seen. I later installed a 0-20 (or maybe 0-15, I had two - one stolen with the van) differential pressure gauge across the same setup.



The only time there was ever any appreciable PSID was during a relief event. That would be where the upstream reading attenuated (it always reached this pressure upon cold start) @ 82psi and the downstream side stopped at a lower level. Then the basement rose to (almost) meet the ceiling. This was always the case.

A loaded filter (9k) merely increased the level of PSID and elongated its duration upon startup ..but produced no substantial static PSID. That is, the 9k filter quickly retreated to 4PSID and then retreated even more as the oil warmed. @150F oil temp, running the rpms up into higher speeds (like the shifting point @ WOT but not achieved using WOT) produced a "surge" of PSID that retreated.

I had more images, but Sony Imagestation went bye-bye. Most of the images from where I had the differential pressure gauge installed ..along with the outside thermometer showing 27F temp ..the start up PSID with a sump full of 15w-40 oil and images at startup ..30sec ..a minute ..a few minutes later on the highway ..etc..etc..etc.


..but kohade, spin'r up

Posted by: SuperBusa

Re: Subaru Oil Pump Specs as Relates to Filter Byp - 04/01/09 01:08 PM

 Originally Posted By: Gary Allan
I stop reading where you go astray. It's that simple. You "force" stuff and merely "work it through" without supporting "here, see?"

You fail to "demonstrate" any sound methodical rationale to support your "stuff". Just stating something is so and expecting it to be that way.

You've focused on just dismissing my assertions and not truly disproving them.


I told you it was a waste of my time. How can you even try to see what I'm saying when you stop reading when you think I "go astray". I read every letter of your sheet and respond with the reasons why I think you've gone astray. If you're not reading and addressing places where you think I'm wrong, then it's just a clear sign that you have a closed mind on this stuff or can't come up with an argument to disprove my inputs.

Bottom line is you can't stand to be wrong, and I'd bet if you all of a sudden realized you were wrong you wouldn't admit to it. Honestly, I would admit that I'm wrong if proven so ... but so far that hasn't happened yet because we have two views on this stuff that just don't correlate with each other on many points - and you have not convinced me otherwise (just like I haven’t' convinced you otherwise). Is it a communication breakdown?? ... could be. But like I said before, the conversation is getting pretty ridiculous and out of focus at this time.

I might try to give you a couple more examples of what I see going on in the oiling system ... if I think it might get something across. What really needs to happen is to get a couple other people involved in this discussion to back up the one who is right ... but apparently nobody wants to voice their insight on this stuff. I will respond to your test setup and info above when I have more time ... you see, I have a full time job that's way more important at times then arguing on the frickin' internet.
Posted by: Gary Allan

Re: Subaru Oil Pump Specs as Relates to Filter Byp - 04/01/09 02:28 PM

So ..I guess you see nothing wrong with my testing procedure or platform ..

..so I have to be a liar or psychotic and imagined it all, right?


...and just to make sure everyone here understands ..


You've NEVER done this type of testing yourself, right???

Thank you very much.
Posted by: SuperBusa

Re: Subaru Oil Pump Specs as Relates to Filter Byp - 04/01/09 04:17 PM

 Originally Posted By: Gary Allan

Again, I can't argue in Ballony's (spell it as you please) world. I told you that from the beginning. What's clear is that you can't work outside of your preconceived box and effectively explain things that are occurring in the real world. While I'm sure Bulloni is right, you can't integrate that there are situations where you've applied universal constants in the wrong proportions.

Concession is conspicuously absent where it should be painfully apparent.

..but you had to be the new sheriff in town ..so


There has been nothing apparent enough to warrant concession on either’s part – obviously. That’s the whole problem here. If you think I’m trying to be “the new sheriff in town”, then that must mean you consider yourself the "current sheriff". Perspective is a funny thing, isn’t it?

Listen, when there are different viewpoints on something, then a debate on why usually happens. If it turns into a pizzing match, or an ego trip, or who’s going to “surrender, or who’s going to concede the most, or who’s really the “sheriff” ... then it’s time to hang up the bullsh*t. I’ve been in plenty of internet battles with people who are on the wrong track about things. It usually doesn’t turn out well if the person in the wrong is so deep seeded in their thoughts that nothing will prove to them that they are off base.

As far a Bernoulli ... well, he was probably a genius for his time and he developed many of the fluid dynamic laws and equations that are still used today in modern engineering. When he’s right, he’s right forever. Physical properties and behaviors on Earth don’t change with time as far as I know.


 Originally Posted By: Gary Allan
So ..I guess you see nothing wrong with my testing procedure or platform ..

..so I have to be a liar or psychotic and imagined it all, right?


...and just to make sure everyone here understands ..


You've NEVER done this type of testing yourself, right???

Thank you very much.


I haven’t sat down long enough to analyze your testing ... so you’ll have to just wait. Just because you ran a test and saw something still means you could have mis-interpreted the results you saw. I’ve been around testing for a long time and believe me, it happens a lot were the test data was mis-interpreted, or in some tests there was not enough data to make the correct conclusion. For instance, in your test how do you know exactly when the filter’s bypass valve was opening? (or not) ... did you have a motion sensor on it that showed exactly when it started opening? Stuff like that may need to be known to make an accurate assessment of what’s really going on.

No, I have not ran the same test you have. Doesn’t mean I don’t know what to expect from the known physics of fluid flow, etc. In real science, the expected results usually match the test results, and that is what gives more validation to the experiment.

Another comment needs to be made. That’s the fact that focus of exactly WTF we are trying to prove to each other has gone completely into the fog zone. I have a feeling that at times we are talking about two different things because the focus is continually changing which makes it very difficult to even communicate effectively.

So, let me ask you .... EXACTLY WHAT is it that you are trying to prove with your experiment? What is the exact fluid dynamic phenomenon this is supposed to prove or disprove? I need to know exactly what you are proving with this experiment before I look closely at the results.
Posted by: Gary Allan

Re: Subaru Oil Pump Specs as Relates to Filter Byp - 04/01/09 06:43 PM

 Quote:
I’ve been around testing for a long time and believe me, it happens a lot were the test data was mis-interpreted, or in some tests there was not enough data to make the correct conclusion.


Absolutely ..and if you care to accept my observations as valid ..and care to offer a plausible alternative school of thought, I'd be more than willing to entertain it. I've "back viewed" cause and effect and constructed the only relationship that is apparent under the presented conditions.

..but you appear to be stuck somewhere else where you have some preconceptions that, while totally valid, aren't nearly as applicable in most of our usage. Kinda like how Audi pointed out the fuel economy advantages of all wheel drive ..but failed to mention that it was at speeds in excess of 100mpg (this was the first Quatro "back in the day")

 Quote:
It usually doesn’t turn out well if the person in the wrong is so deep seeded in their thoughts that nothing will prove to them that they are off base.


I agree. I recommend getting your own setup on an engine and see what you see. I think that it won't change your mind on what you're convinced of. I don't think you're wrong ..but it will open aspects of oil flow and pressure differentials that have not occurred to you.

I wish Bull-oni were here. Really. I think he would say to you, "I understand your confusion, SuperBusa. While Gary is a relative undisciplined neanderthalic fool, he's correctly identified the altered views that one must adopt as one switches from a positive displacement environment to a pressure/resistance environment. Just because he struggles to adequately describe it in terms you can identify ..is not reason to reject it.".
Posted by: Gary Allan

Re: Subaru Oil Pump Specs as Relates to Filter Byp - 04/01/09 07:38 PM

 Quote:
For instance, in your test how do you know exactly when the filter’s bypass valve was opening? (or not)


Sorry, forgot this.

I did see one event where the differential gauge reached the range of the normal Purolator bypass setting on the 9k loaded filter with 15w-40 oil @ 28F with overnight temps of the low 20's/high teens. The condition was brief ..like 30 sec.

With a new Pureone filter, the smallest one that they make in the 3/4-16 thread (or I could find, maybe) ..I thought the gauge was broken. I had to wonder if the blip that I thought I saw was a placebo effect, or some vibration from the engine on initial firing. It was that "unremarkable".

This would not be the situation with all engine/filter combo's. My 2.5 jeep resides at or near the relief level all the time. Depending on what visc oil I use, I would be in some state of elevated PSID based on visc (mostly) whenever off idle. Same with my wife's HV pump's 4.0. Both are slammed up against the relief most of the time. You have to use 20 grade in the 4.0 to "fit" all the volume through at full warm up ..with the 2.5, I THINK, I can manage to get into a decent range of flow within the relief limit. Throw in 5w-40 ..and neither will be out of relief. THEN the PSID will vary depending on visc. The higher PSID will retreat to a lower PSID.


Here's a state that I think you've failed to consider (me too, for that matter). It will probably work with your basic rationale to this whole deal.

If a pump was in perpetual relief, all of your assumptions about filter resistance will be 100% valid (at least I think so). There you would/should have all of your pressure drops responding directly to volume. Cold oil, high PSID, hot oil ..low PSID ..but it would always vary with the volume through it ..high or low. You would still have to figure some way of having the filter reduce it's relative resistance while still dropping the supply across both. I'm not sure (haven't thought it out too far), but I think you would have to see the engine side (on my two gauge setup) dip assuming that you don't exceed the oil pump's relief capacity. Both must add up to supply, so any increase in PSID must reduce the drop across the engine. It would be very odd to see.

I can't think straight at the moment, but I think that this too would require more flow being shunted to the relief.
Posted by: SuperBusa

Re: Subaru Oil Pump Specs as Relates to Filter Byp - 04/01/09 07:56 PM

 Originally Posted By: Gary Allan
..but you appear to be stuck somewhere else where you have some preconceptions that, while totally valid, aren't nearly as applicable in most of our usage. Kinda like how Audi pointed out the fuel economy advantages of all wheel drive ..but failed to mention that it was at speeds in excess of 100mpg (this was the first Quatro "back in the day").


Listen ... like I said earlier, these discussions have put shrapnel all over the place, and the focus we are both on could have went 180 deg out from each other and caused a complete derailment in the discussion. I'm talking about one thing ... you're talking about something else when we think we are talking about the same thing ... so we both think the other one is wrong. I’m hoping that is really the case.

 Originally Posted By: Gary Allan
 Quote:
It usually doesn’t turn out well if the person in the wrong is so deep seeded in their thoughts that nothing will prove to them that they are off base.


I agree. I recommend getting your own setup on an engine and see what you see. I think that it won't change your mind on what you're convinced of. I don't think you're wrong ..but it will open aspects of oil flow and pressure differentials that have not occurred to you.


See what I said just above. These discussions have gone in every direction possible, and we've gotten out of phase along the way. Both gotta re-focus and open the mind, and look at one thing at a time.

 Originally Posted By: Gary Allan
I wish Bull-oni were here. Really. I think he would say to you, "I understand your confusion, SuperBusa. While Gary is a relative undisciplined neanderthalic fool, he's correctly identified the altered views that one must adopt as one switches from a positive displacement environment to a pressure/resistance environment. Just because he struggles to adequately describe it in terms you can identify ..is not reason to reject it.".


Now, now ... don't get too full of yourself just yet. I'm sure 'ol Bernoulli would have a thing or two to say with regard to your understanding and confusion factor at times too. ;\)
Posted by: rcy

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 04/01/09 08:00 PM

Are you guys just doing this to get your post counts up?
Posted by: Gary Allan

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 04/01/09 11:21 PM

Well, now that you mention it , I guess it is a by/co-product
Posted by: SuperBusa

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 04/02/09 01:04 AM

Well, I have to get this message out immediately! After re-reading most of this thread and taking everything into consideration, it looks like I was completely wrong on all accounts!
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
APRIL FOOLS !!!

I had to do an April Fools on someone today ... looked like a prefect opportunity. \:\!

Yes, I will look at the testing stuff and give my thoughts on it in the next day or two. Been really busy this week.
Posted by: rcy

Re: Subaru Oil Pump Specs as Relates to Filter Byp - 04/02/09 06:59 PM

The guy at Wix Canada emailed me back (two emails actually posted below). The first email was sent to me after I emailed him the part # of the Subaru Canada dealer supplied filter. He seems to think it's a repainted FRAM ph3593a.

The second email was in response to my asking him if the dealer supplied filter could actually be made by FRAM but have a higher bypass filter setting (basically I asked if it could be a 3593 internally except for the bypass spring).

What do you all think are the chances that FRAM makes a filter specifically for Subaru that has the higher bypass? The Wix guy seemed to think that the FACTORY filter (which is not a FRAM as far as I can tell) might be 23psi, but the dealer filter would not be. Personally, I can't imagine FRAM making this one filter specifically for Subaru with the 23psi bypass setting but I could be wrong.

_____________________________

this is the subaru canada part number built by fram and it would be the equivalent to a ph3593a.
the valve setting on this filter is 12 psi which is what our filter would be set at as well.
which is the standard by the looks of things i have checked many other filter companys and have not found a filter with that high of a psi rating.

AFFINIA Group Canada, WIX Division
(519) 622-4545 *277

_____________________________________

The filter SCI530001 is the exact interchange to the 3593, valve setting and all.
it looks like the only way we would really be able to see that 23 psi setting would be to do a little research on the actual Original Equipment Manufacturer number.
Is there a number in your repair manual that you could give us and we could see what we find out about that filter?
We need the oem number in order to see the 23 psi valve setting

Thanks

AFFINIA Group Canada, WIX Division
(519) 622-4545 *277

Posted by: bluesubie

Re: Subaru Oil Pump Specs as Relates to Filter Byp - 04/02/09 08:15 PM

Jeez, no wonder I don't visit the filter forum that much. Thanks for your work LoneRanger. \:\!

So as far as aftermarket filters go: 1) Purolator is very close to Subaru's spec and 2) Wix Canada is still researching it. Did I read that correctly? Or did I see a thread earlier saying there was a Wix fitment with 20 psi's? I did lots of skimming due to a spinning head.

Ed - Are you the running OEM FRAM in the LGT?

-Dennis
Amsoil EA on the FXT and down to two Tokyo Roki's for the RS and OB. \:\(
Posted by: edhackett

Re: Subaru Oil Pump Specs as Relates to Filter Byp - 04/02/09 08:45 PM

rcy: The blue Subaru filter is a repainted FRAM 9715 with the proper 23.3 by-pass spring pressure. I cut both apart just a couple of weeks ago.

bluesubie: No I'm not running the OEM FRAM. I have a stash of 13 of the Tokyo Roki filters. I'll probably go with the oversize PureOne when those are gone if Subaru is still using the FRAM filters at that point.

Ed
Posted by: rcy

Re: Subaru Oil Pump Specs as Relates to Filter Byp - 04/05/09 02:28 PM

The blue Subaru filter? Is that the one that comes on the cars from the factory? My stealership only has white ones - here in Canada, they seem to made by Honeywell/Fram, maybe a 3593, but I'm not sure if Fram makes the bypass setting higher to meet Subaru specs, or if it's just a 3593 painted white.
Posted by: CaptainNed

Re: Subaru Oil Pump Specs as Relates to Filter Byp - 04/05/09 04:43 PM

@rcy:

The blue Subaru/Fram filter is Subaru P/N 15208AA12A. Do yourself a favor and spend the money on EBay to find the black Tokyo Roki filters, Subaru P/N 15208AA100.

I'll warn you, though, that since the change to what the Subie community considers a junk Fram filter, the price of Tokyo Rokis is well above what they originally sold for.

Also, if your stealer is still selling you the white filter, that's OK if you're non-turbo or '05 and earlier turbo. The change to the 2.5L turbo for '06 and exhaust rerouting means the white filter is too close to the down pipe and can cook the oil from radiant heat, at least from Subaru's POV.
Posted by: Thingfish

Re: Subaru Oil Pump Specs as Relates to Filter Byp - 04/06/09 06:59 PM

Just found this FWIW,





Posted by: SuperBusa

Re: Subaru Oil Pump Specs as Relates to Filter Byp - 04/08/09 06:42 PM

Well, I finally got a chance to look at this and respond like I said I would. I merged your two posts into one response.

 Originally Posted By: Gary Allan

I used a Permacool sandwich adapter with the poppet relief welded shut. I then routed it to a dual Permacool filter mount where I used a block adapter on one of the filter mounts and a filter on the other. Hence pressure was read above and below the filter. This was routed to the two pressure gauges that you have seen. I later installed a 0-20 (or maybe 0-15, I had two - one stolen with the van) differential pressure gauge across the same setup.



The only time there was ever any appreciable PSID was during a relief event. That would be where the upstream reading attenuated (it always reached this pressure upon cold start) @ 82psi and the downstream side stopped at a lower level. Then the basement rose to (almost) meet the ceiling. This was always the case.

A loaded filter (9k) merely increased the level of PSID and elongated its duration upon startup ..but produced no substantial static PSID. That is, the 9k filter quickly retreated to 4PSID and then retreated even more as the oil warmed. @150F oil temp, running the rpms up into higher speeds (like the shifting point @ WOT but not achieved using WOT) produced a "surge" of PSID that retreated.


Nothing surprising here. Just as I’ve said many times, the max filter PSID and max engine oil pressure will always occur when the pump is in relief mode (under constant viscosity conditions as always). That is because when the pump is in relief mode, the max possible supply pressure is on the filter/engine flow path, and that will produce the max amount of oil flow at that instant in time. The corresponding filter PSID and engine oil pressure at that instant in time will be dependant on the volume & viscosity of the oil flowing through the system.

Of course if the engine PRM is decreased, and/or as the oil starts to warm up, then eventually the pump will go out of relief mode and the filter PSID and engine oil pressure will retreat (decrease) accordingly.

 Originally Posted By: Gary Allan

I did see one event where the differential gauge reached the range of the normal Purolator bypass setting on the 9k loaded filter with 15w-40 oil @ 28F with overnight temps of the low 20's/high teens. The condition was brief ..like 30 sec.


Not surprising. Obviously with oil that viscous the pump was in relief mode supplying its max pressure. Even though the oil flow volume going to the filter/engine was much less, the high viscosity factor has a large influence on filter PSID and engine oil pressure. The filter was probably loaded enough to cause the flow’s volume & viscosity combo to create a PSID greater than the bypass setting. It’s also possible that the system was probably not fully pressurized initially upon startup for the first few seconds (up to 30 sec ?? – who knows) due to the oil being so viscous. This would cause an initial higher “in-rush” oil volume through the filter until the engine circuit was filled to produce the normal backpressure on the system which would then lessen the flow rate and filter’s PSID.

 Originally Posted By: Gary Allan
With a new Pureone filter, the smallest one that they make in the 3/4-16 thread (or I could find, maybe) ..I thought the gauge was broken. I had to wonder if the blip that I thought I saw was a placebo effect, or some vibration from the engine on initial firing. It was that "unremarkable".


I’m assuming the same cold oil start-up conditions applied to this filter? If so, this doesn’t sound like a normal response. I would expect some noticeable/visible PSID at these cold startup conditions with any oil filter in the system. Maybe the gauge didn’t like the cold weather that day, or maybe the bypass valve was stuck open all the time. Hard to say.

 Originally Posted By: Gary Allan
This would not be the situation with all engine/filter combo's. My 2.5 jeep resides at or near the relief level all the time. Depending on what visc oil I use, I would be in some state of elevated PSID based on visc (mostly) whenever off idle. Same with my wife's HV pump's 4.0. Both are slammed up against the relief most of the time. You have to use 20 grade in the 4.0 to "fit" all the volume through at full warm up ..with the 2.5, I THINK, I can manage to get into a decent range of flow within the relief limit. Throw in 5w-40 ..and neither will be out of relief. THEN the PSID will vary depending on visc. The higher PSID will retreat to a lower PSID.


A good reason to ensure the oil filter being used is matched to the vehicle in terms of flow resistance (ie, element size and flow vs PSID characteristics) and bypass valve setting. Just like the Subaru application (high volume oil pump!) this thread is focused on ... if you used a filter with a much lower bypass setting than specified, the filter could certainly be in bypass mode much more and much longer than really desired. I think we all have agreed to that conclusion.

 Originally Posted By: Gary Allan
Here's a state that I think you've failed to consider (me too, for that matter). It will probably work with your basic rationale to this whole deal.

If a pump was in perpetual relief, all of your assumptions about filter resistance will be 100% valid (at least I think so). There you would/should have all of your pressure drops responding directly to volume. Cold oil, high PSID, hot oil ..low PSID ..but it would always vary with the volume through it ..high or low.


True ... there will always be a pressure drop across a device that is resistant to flow, and the associated pressure drop will be proportional to the flow volume and fluid viscosity.

 Originally Posted By: Gary Allan
You would still have to figure some way of having the filter reduce it's relative resistance while still dropping the supply across both. I'm not sure (haven't thought it out too far), but I think you would have to see the engine side (on my two gauge setup) dip assuming that you don't exceed the oil pump's relief capacity. Both must add up to supply, so any increase in PSID must reduce the drop across the engine. It would be very odd to see.

I can't think straight at the moment, but I think that this too would require more flow being shunted to the relief.


If the pump is in relief mode and viscosity constant, then of course any increase in filter PSID (due to loading, etc) will cause a decrease in the engine oil pressure reading (sensor after the filter). Ideally, if more flow was shunted out the relief valve to the sump, then there should be a corresponding drop in both filter PSID and engine oil pressure after the relief valve has stabilized the flow conditions.

One thing never discussed yet is how does the flow resistance of the filter and engine chance with thermal effects. In other words, does the filter and engine flow resistance change as they heat up? It’s entirely possible that the engine’s flow path becomes less restrictive as all the parts heat up and expand (ie, bearing clearances increase), which could dynamically change the flow resistance ratio of the filter/engine circuit. I can’t really see how an oil filter’s flow resistance would decrease as it heated up, but if it did, due to the element material “opening up”, you would also think it’s filtering performance might also change some (become worse) with its temperature.
Posted by: Gary Allan

Re: Subaru Oil Pump Specs as Relates to Filter Byp - 04/08/09 07:38 PM

Here's where we differ. While you appear to agree on the conditions, the "cause" and the ending of the condition seem to "slide" a little

 Quote:
Just as I’ve said many times, the max filter PSID and max engine oil pressure will always occur when the pump is in relief mode (under constant viscosity conditions as always).


Here we're in apparent agreement.

 Quote:
That is because when the pump is in relief mode, the max possible supply pressure is on the filter/engine flow path, and that will produce the max amount of oil flow at that instant in time.


..and here we're mostly in agreement ..but we're creeping (I can feel it)

 Quote:
The corresponding filter PSID and engine oil pressure at that instant in time will be dependant on the volume & viscosity of the oil flowing through the system.


Well .. here's what this statement doesn't resolve. As soon as the relief event is over ..with the same (near enough) viscosity and alleged filter resistance ..the PSID evaporates.

That's not apparent in that statement. It's PURELY because of the relief event that the filter presents so much resistance. The filter obviously doesn't change in any property from one state to the other ..nor does the viscosity (appreciably) ..so the applied physics must be altered. That is, the equation has to change to fit the apparent readings since the physical properties cannot (massage that to make sense).

This can also be the case where a stationary column of oil hasn't transitioned to a moving column of oil. The effects would appear the same.

The filter is exactly what it was. The oil (for the sake of discussion) was exactly what it was. The difference is the amount of oil shunted in relief. The more flow shunted, the more the apparent PSID. No shunted flow, no apparent (substantial) PSID (at sensible volumes).


 Quote:
I’m assuming the same cold oil start-up conditions applied to this filter? If so, this doesn’t sound like a normal response. I would expect some noticeable/visible PSID at these cold startup conditions with any oil filter in the system. Maybe the gauge didn’t like the cold weather that day, or maybe the bypass valve was stuck open all the time. Hard to say.


Not quite as cold ..but run for weeks with no reaction. It was a transitional time of the year.

Relief events were rare with this engine. Start up pressure ALWAYS went to 82psi on a cold start. The difference would be how long 82 was maintained. The difference was about 2psi above:below.

 Quote:
A good reason to ensure the oil filter being used is matched to the vehicle in terms of flow resistance (ie, element size and flow vs PSID characteristics) and bypass valve setting. Just like the Subaru application this thread is focused on ... if you used a filter with a much lower bypass setting than specified, the filter could certainly be in bypass mode much more and much longer than really desired. I think we all have agreed to that conclusion.


Here we're somewhat (and mostly) in agreement. The exception with the Subaru is that it's only due to its extreme volume where this would be a factor. The pressures that the engine produces are broad. That is, they aren't operating 24/7 at the relief level.


 Quote:


One thing never discussed yet is how does the flow resistance of the filter and engine chance with thermal effects. In other words, does the filter and engine flow resistance change as they heat up? It’s entirely possible that the engine’s flow path becomes less restrictive as all the parts heat up and expand (ie, bearing clearances increase), which could dynamically change the flow resistance ratio of the filter/engine circuit. I can’t really see how an oil filter’s flow resistance would decrease as it heated up, but if it did, due to the element material “opening up”, you would also think it’s filtering performance might also change some (become worse) with its temperature.


Depending on how you're viewing it, the "apparent" resistance of the filter will be changed or unchanged with a decrease in viscosity. Out of relief you'll see virtually no PSID ..so it's mostly independent of visc and more a function of pressure limits. That is 85lb out of relief, next to nothing. 85lb in relief ..something.

10CST fluid flows much easier through a filter than 140CST fluid. The same as it requires less "power" to push it through the engine. Again, it's not an issue at most sensible flow rates and the difference is (probably) measured in inches of water column. The turnstile that you think is slowing you up is nothing when the traffic jam is all the way to the exit. An engine is always a traffic jam to the exit. Out of relief, you can't be "slowed up" in a fully enveloped engine. You can just move easier (at whatever flow rate that is at the moment). The fluid will just accelerate or decelerate with the relative size of the conduit that it's transitioning to.
Posted by: Thingfish

Re: Subaru Oil Pump Specs as Relates to Filter Byp - 04/08/09 11:10 PM

What I am having a problem wrapping my mind around is that if the filters we use have a maximum flow rate of 9 gpm, and the Subaru can deliver up to almost 17 gpm ( 12mm rotors ), wouldn't the filter ALWAYS be in bypass if is was only 8-11 psid? And making the bypass stiffer, would force it to flow through the element instead of bypassing it?

Bear with me, there are much sharper knives in the drawer....


Fwiw, next time I have a block here, I am interested to measure the oil galleys..

Posted by: Gary Allan

Re: Subaru Oil Pump Specs as Relates to Filter Byp - 04/09/09 10:38 AM

 Quote:
What I am having a problem wrapping my mind around is that if the filters we use have a maximum flow rate of 9 gpm, and the Subaru can deliver up to almost 17 gpm ( 12mm rotors ), wouldn't the filter ALWAYS be in bypass if is was only 8-11 psid?



No. It would only be in bypass, due to volume, somewhere above 9-11 gpm (or wherever the filter itself became a factor). It could become a factor of measurable merit at 6 or 7. I've personally never seen it in most routine driving ..which would include some WOT to the shifting point on my 3.0 Mitsubishi ..which would sensibly be somewhere in the 5000rpm+ range.

 Quote:
And making the bypass stiffer, would force it to flow through the element instead of bypassing it?


Yes.

At some point in volume, the media is going to look like a solid piece of cardboard. Just up the volume to 50gpm.

..but how many times does anyone push that much oil through the engine?

This may surely be a requirement of that little pesky screen for the turbo, but it is more likely needed to filter more during the startup process, which you dwell at every time you turn it on, rather than the 6000 rpm level which you dwell at very little. It would also work well at that level of operation.

You're going to have a high(er) differential across the filter every time you start it up due to being in relief far more often then you're going to have an elevated differential due to volume. That is, unless you live in AZ or NV or some other open space place where you can literally drive hours at some high speed.

You may or may not be in bypass at every startup ..but you'll be at some elevated PSID every time you're in relief. If we accept that the turbo owner's gauge is somewhat accurate, the PSID will vary depending on the visc of the oil at that starting temp, and how fast the engine is operated before it is reduced in visc enough to "fit" full volume (whatever the pump is putting out= at THAT time)through the engine.
Posted by: Thingfish

Re: Subaru Oil Pump Specs as Relates to Filter Byp - 04/09/09 12:23 PM

I see, I believe I am starting to get the idea.. But will continue to pay attention.



Thank you Mr.Allan.
Posted by: Gary Allan

Re: Subaru Oil Pump Specs as Relates to Filter Byp - 04/09/09 12:36 PM

It's a very difficult thing to articulate. You, more or less, have to observe it and back construct the reasons from the apparent results. I'm sure some engineer somewhere knows exactly how to state this, but may not be able to in a way we can understand. I can see the effects, but can't fully articulate the theoretical mechanisms employed to satisfy some ..this includes myself. I'm sure there are tons of things you've figured out the cause and effect relationship on ..but can't "get there" in true definition. So, you do the best you can to describe how you came to your conclusions and leave the absolute finer details to someone who can.

A filter is not an easy thing for oil, at any visc, to pass through. Surely if one compares it to just pouring it out of a bottle. It's only when there's a much more restrictive element downstream of it does it get reduced to "also ran". This is unique to flow dictated scenarios. It's not like water faucets or electrical outlets or garden hoses.

It's like a pressure washer. You put in a smaller nozzle, the water travels faster at the same volume. If you had a 2" hose ..or one slightly smaller, the nozzle would still be the one element that's bringing the pump up to the (near) 2500psi (or whatever) level where it's operating at. If water didn't have the VI that it does, you would see your water stream go limp ..the pressure you developed would tank..but the volume would remain the same. You could put a filter of whatever restrictive property you please in line (assuming that you used one that could withstand 2500 psi) and the flow wouldn't even see it.

Posted by: deeter16317

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 04/09/09 01:02 PM

 Originally Posted By: SuperBusa


I agree that it seems like a HUGE (and unbelievable) amount of oil volume output from the oil pump. It very well could be a typo, but who can prove it? I don’t think my garden hose even flows at 12 gpm.



I have no doubt the pump will free flow that much...it probably will flow that much, and more (since that is most likely a "minimum" specification. But the engine (or more specifically engine clearances) is the restriction. You could have a pump that is capable of free flowing 50,000GPM, but if you are trying to force it through a 1/4" diameter hole, it won't/can't flow anywhere near its rated flow. That's because the restriction is the factor regulating the flow rate.

Another point is the fact the filter is pressurized. You would need to have a 8-11psi drop across the filter media in order to have the bypass open. That would imply the filter media is really being restrictive by itself correct?? Would a fresh filter be that restrictive (at normal operating temperatures)??

Just some food for thought...
Posted by: deeter16317

Re: Subaru Oil Pump Specs as Relates to Filter Byp - 04/09/09 01:06 PM

 Originally Posted By: Gary Allan
It's a very difficult thing to articulate. You, more or less, have to observe it and back construct the reasons from the apparent results. I'm sure some engineer somewhere knows exactly how to state this, but may not be able to in a way we can understand. I can see the effects, but can't fully articulate the theoretical mechanisms employed to satisfy some ..this includes myself. I'm sure there are tons of things you've figured out the cause and effect relationship on ..but can't "get there" in true definition. So, you do the best you can to describe how you came to your conclusions and leave the absolute finer details to someone who can.

A filter is not an easy thing for oil, at any visc, to pass through. Surely if one compares it to just pouring it out of a bottle. It's only when there's a much more restrictive element downstream of it does it get reduced to "also ran". This is unique to flow dictated scenarios. It's not like water faucets or electrical outlets or garden hoses.

It's like a pressure washer. You put in a smaller nozzle, the water travels faster at the same volume. If you had a 2" hose ..or one slightly smaller, the nozzle would still be the one element that's bringing the pump up to the (near) 2500psi (or whatever) level where it's operating at. If water didn't have the VI that it does, you would see your water stream go limp ..the pressure you developed would tank..but the volume would remain the same. You could put a filter of whatever restrictive property you please in line (assuming that you used one that could withstand 2500 psi) and the flow wouldn't even see it.




In your model, you indicate the pressure washer nozzle is the filter; however the restriction is internal in the engine, downstream of the filter.

So the filter would be somewhere along the supply hose in your example and the engine would be the restriction/nozzle...while there may be a huge pressure differential at the engine/nozzle, there is potentially very little across the filter itself...

Make sense?
Posted by: Gary Allan

Re: Subaru Oil Pump Specs as Relates to Filter Byp - 04/09/09 02:57 PM

 Quote:
In your model, you indicate the pressure washer nozzle is the filter;


No ..I'm offering that the nozzle is the engine ..and that the hose, and anything that you would likely put in line, is the filter ...accounting for very little in most modes of operation.

 Quote:
So the filter would be somewhere along the supply hose in your example and the engine would be the restriction/nozzle...while there may be a huge pressure differential at the engine/nozzle, there is potentially very little across the filter itself...


Exactly.

 Quote:
Make sense?


Has to me since I installed those gauges and observed them for many months ..many moons ago

Getting others to accept that for most people that there is no "free flowing" or "tight" filter is another story. For most of us, the filter is invisible.
Posted by: SuperBusa

Re: Subaru Oil Pump Specs as Relates to Filter Byp - 04/09/09 06:19 PM

 Originally Posted By: Gary Allan
Here's where we differ. While you appear to agree on the conditions, the "cause" and the ending of the condition seem to "slide" a little

 Quote:
Just as I’ve said many times, the max filter PSID and max engine oil pressure will always occur when the pump is in relief mode (under constant viscosity conditions as always).


Here we're in apparent agreement.


Amazing


 Originally Posted By: Gary Allan

 Quote:
That is because when the pump is in relief mode, the max possible supply pressure is on the filter/engine flow path, and that will produce the max amount of oil flow at that instant in time.


..and here we're mostly in agreement ..but we're creeping (I can feel it)


It’s a true statement as written – can’t argue the truth; no “creeping” here. So far so good.


 Originally Posted By: Gary Allan

 Quote:
The corresponding filter PSID and engine oil pressure at that instant in time will be dependant on the volume & viscosity of the oil flowing through the system.


Well .. here's what this statement doesn't resolve. As soon as the relief event is over ..with the same (near enough) viscosity and alleged filter resistance ..the PSID evaporates.

That's not apparent in that statement. It's PURELY because of the relief event that the filter presents so much resistance. The filter obviously doesn't change in any property from one state to the other ..nor does the viscosity (appreciably) ..so the applied physics must be altered. That is, the equation has to change to fit the apparent readings since the physical properties cannot (massage that to make sense).


Keep in mind that in order for the pump to go out of relief mode that means one or both of two things must happen: a) the oil viscosity is becoming much less, and/or b) the engine RPM has decreased enough to significantly reduce the pump’s output volume. When both things are happening at once, very dynamic conditions can occur.

If the viscosity is becoming so thin enough that the pump goes out of relief mode, then the filter PSID will also drop accordingly. If the engine RPM decreases, the flow volume also goes down and the filter’s PSID will also drop accordingly. I don’t think you are seeing anything “magical” with your limited experimental observations.

Keep in mind that these relationships between flow, pressure and oil viscosity are not linear, and as such you could see some drastic differences in filter PSID between conditions where the pump is in relief and not in relief.


 Originally Posted By: Gary Allan

The filter is exactly what it was. The oil (for the sake of discussion) was exactly what it was. The difference is the amount of oil shunted in relief. The more flow shunted, the more the apparent PSID. No shunted flow, no apparent (substantial) PSID (at sensible volumes).


I think you are veering off track some here. For the pump to go out of relief mode, there has to be a reason for it to happen. Like I said above, it can be either: a) the oil viscosity is becoming much less, and/or b) the engine RPM has decreased enough to significantly reduce the pump’s output volume.

If the pump goes out of relief mode with the engine at a constant RPM, then the oil is not “exactly what it was” ... it is becoming thinner – otherwise the pump would not go out of relief mode.

The filter PSID is higher when the pump is in relief mode with cold oil because the combination of the lower flow volume with a higher oil viscosity creates a larger PSID then when the pump is out of relief and the combination of higher flow volume with a lower oil viscosity.

Low flow volume + high viscosity can cause more PSID than high flow volume + low viscosity. You must realize that both of these parameters are the sole cause of pressure drop. This is why you see less PSID when out of pump relief, even though the flow volume is much higher. The viscosity is probably a stronger factor than flow volume on the observed PSID.


 Originally Posted By: Gary Allan

 Quote:
I’m assuming the same cold oil start-up conditions applied to this filter? If so, this doesn’t sound like a normal response. I would expect some noticeable/visible PSID at these cold startup conditions with any oil filter in the system. Maybe the gauge didn’t like the cold weather that day, or maybe the bypass valve was stuck open all the time. Hard to say.


Not quite as cold ..but run for weeks with no reaction. It was a transitional time of the year.

Relief events were rare with this engine. Start up pressure ALWAYS went to 82psi on a cold start. The difference would be how long 82 was maintained. The difference was about 2psi above:below.


My take is that this engine’s oil pump probably doesn’t put out very much oil volume and/or the engine’s flow path is pretty restrictive thereby significantly reducing the flow volume through the filter/engine when the pump was in relief mode with cold oil. If the cold oil flow volume is very low, then of course you won’t see much filter PSID even though the oil pump is in relief at 82 psi. Just because you have high oil pressure doesn’t always mean there will be lots of flow volume – it all depends on the flow resistance of engine. Even though the oil was cold and viscous, the volume was probably so low going through the filter/engine path at this point in time that the filter PSID was also low. Plus you said the filter was a brand new (PureOne) and would have been as free flowing as possible at the time. Without having an actual flow meter in the test, you really have no idea what the actual flow volume is ... and the flow volume is a major factor in the filter PSID you will see on your delta P gauge. Without an actual flow meter you don’t see the whole story to fit all the pieces together. I really see nothing that you have seen with your gauges that can’t be explained.

This again goes full circle with regard to the oil filters used on HV oil pumps like the Subaru’s. If and engine’s flow path is relatively free flowing (ie, less restrictive than most cars), then a HV oil pump will be able to force a lot higher oil volume of cold oil through the circuit. And if the oil filter doesn’t have the bypass valve set high enough, then there will definitely be more frequent and longer bypass events as a result – especially during engine cold and warm-up run time. This is exactly why Subaru has specified a 23 psi filter bypass.


 Originally Posted By: Gary Allan

 Quote:
A good reason to ensure the oil filter being used is matched to the vehicle in terms of flow resistance (ie, element size and flow vs PSID characteristics) and bypass valve setting. Just like the Subaru application this thread is focused on ... if you used a filter with a much lower bypass setting than specified, the filter could certainly be in bypass mode much more and much longer than really desired. I think we all have agreed to that conclusion.


Here we're somewhat (and mostly) in agreement. The exception with the Subaru is that it's only due to its extreme volume where this would be a factor. The pressures that the engine produces are broad. That is, they aren't operating 24/7 at the relief level.


Agreed ... see above. Of course the filter won’t be in bypass 100% of the time when the oil is nice and hot, even if the filter had an 8~11 psi bypass. I have qualified the statement many times in the past in this thread that it would mostly be a potential problem only during engine cold starts and warm-up run times.


 Originally Posted By: Gary Allan

 Quote:
One thing never discussed yet is how does the flow resistance of the filter and engine chance with thermal effects. In other words, does the filter and engine flow resistance change as they heat up? It’s entirely possible that the engine’s flow path becomes less restrictive as all the parts heat up and expand (ie, bearing clearances increase), which could dynamically change the flow resistance ratio of the filter/engine circuit. I can’t really see how an oil filter’s flow resistance would decrease as it heated up, but if it did, due to the element material “opening up”, you would also think it’s filtering performance might also change some (become worse) with its temperature.


Depending on how you're viewing it, the "apparent" resistance of the filter will be changed or unchanged with a decrease in viscosity. Out of relief you'll see virtually no PSID ..so it's mostly independent of visc and more a function of pressure limits. That is 85lb out of relief, next to nothing. 85lb in relief ..something.

10CST fluid flows much easier through a filter than 140CST fluid. The same as it requires less "power" to push it through the engine. Again, it's not an issue at most sensible flow rates and the difference is (probably) measured in inches of water column. The turnstile that you think is slowing you up is nothing when the traffic jam is all the way to the exit. An engine is always a traffic jam to the exit. Out of relief, you can't be "slowed up" in a fully enveloped engine. You can just move easier (at whatever flow rate that is at the moment). The fluid will just accelerate or decelerate with the relative size of the conduit that it's transitioning to.


See previous response above about the effect of the volume + viscosity parameter combination on the effect of pressure drop. It’s not a linear relationship, and once the pump is out of relief mode there can certainly be a drastic fall off of PSID as compared to relief mode. I’ve never argued any differently, and if you could looked at the actual flow and viscosity measurements during all of these conditions you’d see it all correlates. There is still a filter PSID (no matter how small) and an engine pressure drop from supply to sump. The fact is if you increased the flow volume without changing anything else in the system, you will see increased pressure drops. If you increased the oil viscosity without changing anything else, you will see increased pressure drops. If you change both at once you will see the effects of both, and which ever factor is stronger will determine the actual pressure drop.

It’s the combination of these two factors that will determine the actual pressure drops you see. Not all engines are the same and not all filters are the same; therefore it’s possible that a particular filter on a particular engine could certainly be cause for concern. Prime example – putting a relatively restrictive filler with a low bypass valve setting on a high flow volume engine system like the Subaru’s will cause the filter to behave differently than it if was put on a 1975 6-banger Econoline Van with a low flow volume oiling system.

I’ve stayed true to this fact from day one ... regardless of the convoluted discussions we have had on this subject. Obviously, we’ve both dug deeper into these discussions and have probably filleted in more ways than one.
Posted by: SuperBusa

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 04/09/09 06:25 PM

 Originally Posted By: deeter16317
 Originally Posted By: SuperBusa


I agree that it seems like a HUGE (and unbelievable) amount of oil volume output from the oil pump. It very well could be a typo, but who can prove it? I don’t think my garden hose even flows at 12 gpm.



I have no doubt the pump will free flow that much...it probably will flow that much, and more (since that is most likely a "minimum" specification. But the engine (or more specifically engine clearances) is the restriction. You could have a pump that is capable of free flowing 50,000GPM, but if you are trying to force it through a 1/4" diameter hole, it won't/can't flow anywhere near its rated flow. That's because the restriction is the factor regulating the flow rate.


Keep in mind that those Subaru oil pump flow specs are listed at a specific engine RPM, oil temp (ie, viscosity) and pressure. This tells me that the pump is flowing into some kind of resistance (same as the engine's?? - who knows?), not open output flow.

 Originally Posted By: deeter16317
Another point is the fact the filter is pressurized. You would need to have a 8-11psi drop across the filter media in order to have the bypass open. That would imply the filter media is really being restrictive by itself correct?? Would a fresh filter be that restrictive (at normal operating temperatures)??

Just some food for thought...


Yes, of course the filter is being restrictive by itself ... just like this graph shows for example.



How much flow restriction depends on the design of the element for the most part - and of course the PSID across the filter is dependant on the oil's viscosity and flow volume going through it. If the element is small and uses very restrictive media, then it will be much more restrictive than if it was large and had free flowing media. Not all filters are equal ... but most are probably pretty close because the filter designers (if they know what they are doing) should take flow vs PSID (and bypass valve setting) into prime consideration for each application - ideally speaking of course.
Posted by: Gary Allan

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 04/09/09 06:59 PM

 Quote:
Not all filters are equal ... but most are probably pretty close because the filter designers (if they know what they are doing) should take flow vs PSID (and bypass valve setting) into prime consideration for each application - ideally speaking of course.


I disagree. It's only the exceptional engine that needs anything other than the generic bypass valve. That's why Wix offers 8-11 for the vast majority ..and Purolator offers 12-16. This is regardless (mostly) of the filter size or application. It is only the exceptional that requires anything other than generic.
Posted by: WagonBoss

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 04/09/09 07:39 PM

I've followed the discussion with great interest. Quite educational. Though I don't know that I can make practical sense of the information. I'd appreciate any discussion on the below questions.

If your choices for a filter were the current OEM replacement with the assumed correct BPV rating manufactured for Subaru by Honeywell, a Wix/Napa Gold 1356 (slightly longer and 8-11 psi BPV), or a Purolator PL14460 (a back-spec'd filter to pre-2005 and the original size and correct 23 PSID BPV rating when Purolator made Subaru filters, which would you choose?

The recommended oil is 5w-30. If one wanted to run a heavier 20w-50 or 15w-40 (perhaps towing or track duty in the summer) would you want a lower or same rating on the BPV?
Posted by: SuperBusa

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 04/09/09 07:54 PM

 Originally Posted By: Gary Allan
 Quote:
Not all filters are equal ... but most are probably pretty close because the filter designers (if they know what they are doing) should take flow vs PSID (and bypass valve setting) into prime consideration for each application - ideally speaking of course.


I disagree. It's only the exceptional engine that needs anything other than the generic bypass valve. That's why Wix offers 8-11 for the vast majority ..and Purolator offers 12-16. This is regardless (mostly) of the filter size or application. It is only the exceptional that requires anything other than generic.


I’ve concluded you’ll look for anything to argue about. Re-read what I said ... it implies the same thing you said, that there are certainly filters that ARE different because of their intended application. If an “exceptional engine” needs anything “other than the generic bypass valve”, then it’s not the same as other filters, now is it? Case in point ... Subaru with the 23 psi bypass valve ... it is NOT your “generic bypass valve”. Stop arguing about the same things you turn around and agree with ... it's a bad habit.
Posted by: SuperBusa

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 04/09/09 08:00 PM

 Originally Posted By: WagonBoss

If your choices for a filter were the current OEM replacement with the assumed correct BPV rating manufactured for Subaru by Honeywell, a Wix/Napa Gold 1356 (slightly longer and 8-11 psi BPV), or a Purolator PL14460 (a back-spec'd filter to pre-2005 and the original size and correct 23 PSID BPV rating when Purolator made Subaru filters, which would you choose?


If it was my Subaru, I'd run the best filter that has the 23 psi bypass valve.

 Originally Posted By: WagonBoss
The recommended oil is 5w-30. If one wanted to run a heavier 20w-50 or 15w-40 (perhaps towing or track duty in the summer) would you want a lower or same rating on the BPV?


You certainly wouldn't want a lower bypass valve setting with thicker oil ... that's going in the wrong direction. I'd say the 23 psi bypass would be OK with the heavier oil also. What choice do you have? ... none really, since there isn't a filter for your car that has a higher than 23 psi bypass valve.
Posted by: Gary Allan

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 04/09/09 08:15 PM

 Originally Posted By: SuperBusa
 Originally Posted By: Gary Allan
 Quote:
Not all filters are equal ... but most are probably pretty close because the filter designers (if they know what they are doing) should take flow vs PSID (and bypass valve setting) into prime consideration for each application - ideally speaking of course.


I disagree. It's only the exceptional engine that needs anything other than the generic bypass valve. That's why Wix offers 8-11 for the vast majority ..and Purolator offers 12-16. This is regardless (mostly) of the filter size or application. It is only the exceptional that requires anything other than generic.


I’ve concluded you’ll look for anything to argue about. Re-read what I said ... it implies the same thing you said, that there are certainly filters that ARE different because of their intended application. If an “exceptional engine” needs anything “other than the generic bypass valve”, then it’s not the same as other filters, now is it? Case in point ... Subaru with the 23 psi bypass valve ... it is NOT your “generic bypass valve”. Stop arguing about the same things you turn around and agree with ... it's a bad habit.


..but that's not ALL you included in your assertion...

you tend to attempt to "slide" something in there as a universal truth ..when it's an exceptional one.

It's a bad habit you have
Posted by: Thingfish

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 04/09/09 08:47 PM

 Originally Posted By: SuperBusa
[quote=WagonBoss]
What choice do you have? ... none really, since there isn't a filter for your car that has a higher than 23 psi bypass valve.


Unless you consider the Canton-Mecca design that has no pbv.
Posted by: unDummy

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 04/09/09 08:54 PM

4 pages of fun here.

You can debate flow, bypass pressure, relief pressure.... until the sun doesn't shine.

A filter will affect flow volume. This is why some engines make a little more noise or clatter with restrictive filters like Pureone or Toughgard. There is no excuse otherwise.

What is good is that page copied from the Subaru factory manuals. See the clearances and their tolerances. Depending on the pump, the accuracy of the springs..... you can have a decrease in oil volume. Every bit of resistance to flow will reduce the pumps ability to pump. Working with fixed rpm motor driven industrial lubrication pumps, one will learn what pump-slip is.

Your oil pump is like your engine. It has blowby like your engine. That is wasted pumpability. Slip can be increased by a worn out pump(which pumps a good volume with no resitance), and then pumps nothing when you put a load on it. Slip can be increased by a pump with wide tolerances and loose clearances. Slip can be increased by the load, whether the resistance caused by the fluid being too thick, or by the engine passages. EVERY nook/cranny in your lubrication system affects flow/pressure and that will affect the pump-slip directly.

The oil filter is the 1st restriction that your pump sees. As the 1st restriction, it will affect every restriction downstream. And, the last circuit(valvetrain), might just feel that restriction and be poortly lubed.

Another slip example is your air powered tools. You can pump 100psi into that worn out impact wrench and get no work done(all slip/blowby = no torque). Give that impact wrench a shot of airtool oil and suddenly you can do work with low 30psi(compression=torque).

Your oil pump is no different.

The high PSI filter relief is simply to get more oil through the filter. Maybe some engynaire measured an increase in wear somewhere in the engine caused by unfiltered oil. German engines also tend to have higher PSI bypass valves. If you have an abundance in flow, then a little bit wasted on forcing more oil through the filter media to possibly reduce 'dirty' motor oil releated issues.

Don't assume your pump is perfect. Don't expect the pump's relief valve(or the filters bypass) to be a perfect poppit on/off switch. It probably leaks a little at idle and more as the pressure on it increases until it is open all the way(at its rating +/- whatever the tolerance is on that rating). Because your engine isn't perfect, what happens in the classroom doesn't always carry into the engine.
Posted by: Gary Allan

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 04/10/09 02:37 AM

While there are all those nuances and enclaves of truth in your statements, undummy, the vast majority don't experience any of them. Those who hear lingering start up rattle that is altered by filter choice ..are nothing in number compared to the millions of units that do not. While oil pumps are not perfect, most losses are minor and are taken for granted as non-influential for discussion's sake.

There are always exceptions. Exceptionally worn pump vanes/gears/rotors ..exceptionally high volumes ..and exceptionally high pressures. The only common theme to all of them is that they are exceptional.

I learned none of this in a classroom.
Posted by: bluesubie

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 04/10/09 12:51 PM

This response from SoA posted on nasioc is very interesting:

 Quote:
Thank you for taking the time to contact us. We appreciate that you brought your concern with the oil filter we now offer for our vehicles. The prior oil filters did not meet the standards of Subaru. This is why our manufacturer diligently worked to redesign the oil filter so that it meets our standards. Subaru is not aware of any recurring concerns with our new oil filter...


I wonder if it's true or they didn't want to say they went cheaper?

-Dennis
Posted by: LoneRanger

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 04/10/09 01:17 PM

WHAT?! I cannot believe the black Tokyo Roki filter did not meet standards. I think that SOA response is smoke and mirrors covering up for, as you indicated, a bean counting decision to go cheaper on an OE part. The Tokyo Roki filter was a quality piece. I wish whoever corresponded with SOA would have sent them a photo of the new Honeywell blue filter and the Tokyo Roki filter side by side, cut open.

Over on Subaruforester.org, there is a vendor (a Subaru dealership) stocking a "Six Star" branded filter that looks quite similar to the black Tokyo Roki... I am trying to find out the BPV spec on it.

Posted by: SuperBusa

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 04/10/09 01:26 PM

 Originally Posted By: unDummy

The high PSI filter relief is simply to get more oil through the filter.


What?! ... how can that be if Gary claims "all filters are the same". Last time I checked, 23 was a different value than 8. I guess Gary's math is pretty strange when 23 = 8.
Posted by: LoneRanger

Wix response to my inquiry on 51365 filter - 04/10/09 01:28 PM

My question:

Using your oil filter # 51365 on my 2009 Subaru Forester. I'm one of those filter geeks that cuts open filters to see how well made they are. Yours is well made. But I have one concern maybe you can put to rest. Bypass pressure for the 51365 is 11 psi according to tech specs on your website. I have since found out that Subaru OE filter bypass pressure is 23psi (!) Is it okay to run that much lower of a bypass pressure spec will the 51365 be in partial bypass most of the time? Or is the bypass rating more dependent on the flow rating of the filter itself and therefore my concern is baseless? Brand new car, just trying to make sure.

Wix response:

Thank you for your inquiry.
At three gallons per minute, the WIX 51365 will produce 2 pounds or less of differential pressure. Differential pressure is the measured pressure drop across the filter assembly. Therefore, the 51365 will have to trap and hold so much contamination that the differential pressure would increase over initial by approximately six times. Should this situation occur, the filter element would be completely plugged (regardless of brand). While it is accurate that a 23 PSID valve will not open until such time as the differential pressure drop meets or exceeds the valve spring force, this would not be an item of concern. Filters do not increase in differential pressure in a linear manner. Rather they gradually build in differential pressure until there is typically 15 % or so of the media's capacity remaining. At this point, the restriction curve rapidly increases and the filter quickly becomes plugged.
For more information on how the full flow filter bypass valve functions, as well as other information, we would encourage you to register and take the free on line E-Learning we have available at http://www.wixfilters.com.
Posted by: SuperBusa

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 04/10/09 01:29 PM

 Originally Posted By: Gary Allan
 Originally Posted By: SuperBusa
 Originally Posted By: Gary Allan
 Quote:
Not all filters are equal ... but most are probably pretty close because the filter designers (if they know what they are doing) should take flow vs PSID (and bypass valve setting) into prime consideration for each application - ideally speaking of course.


I disagree. It's only the exceptional engine that needs anything other than the generic bypass valve. That's why Wix offers 8-11 for the vast majority ..and Purolator offers 12-16. This is regardless (mostly) of the filter size or application. It is only the exceptional that requires anything other than generic.


I’ve concluded you’ll look for anything to argue about. Re-read what I said ... it implies the same thing you said, that there are certainly filters that ARE different because of their intended application. If an “exceptional engine” needs anything “other than the generic bypass valve”, then it’s not the same as other filters, now is it? Case in point ... Subaru with the 23 psi bypass valve ... it is NOT your “generic bypass valve”. Stop arguing about the same things you turn around and agree with ... it's a bad habit.


..but that's not ALL you included in your assertion...

you tend to attempt to "slide" something in there as a universal truth ..when it's an exceptional one.

It's a bad habit you have


You're really getting hopeless. Looks like you've been demoted to deputy status with one bullet in your shirt pocket (if ya know what I mean ;\) ).
Posted by: SuperBusa

Re: Wix response to my inquiry on 51365 filter - 04/10/09 01:38 PM

 Originally Posted By: LoneRanger


Wix response:

Thank you for your inquiry.
At three gallons per minute, the WIX 51365 will produce 2 pounds or less of differential pressure. Differential pressure is the measured pressure drop across the filter assembly. Therefore, the 51365 will have to trap and hold so much contamination that the differential pressure would increase over initial by approximately six times. Should this situation occur, the filter element would be completely plugged (regardless of brand). While it is accurate that a 23 PSID valve will not open until such time as the differential pressure drop meets or exceeds the valve spring force, this would not be an item of concern. Filters do not increase in differential pressure in a linear manner. Rather they gradually build in differential pressure until there is typically 15 % or so of the media's capacity remaining. At this point, the restriction curve rapidly increases and the filter quickly becomes plugged.
For more information on how the full flow filter bypass valve functions, as well as other information, we would encourage you to register and take the free on line E-Learning we have available at http://www.wixfilters.com.


The problem I see in the response from WIX is that they are only talking about the PSID due to filter loading with time - and I think are assuming flow conditions with oil at full operating temps. They never talk about the increased PSID during cold start and engine warm-up transitional time with increased engine RPMs.

I'd email WIX back and pose those specific running conditions to see how he responds knowing their filter has a much lower bypass setting than the Subaru spec. There's no doubt that when the oil is nice and hot that 8~11 psi bypass would probably be OK ... but what about with cold thick oil at startup and during engine warm-up. That has been the focus of this whole discussion from page one.
Posted by: SuperBusa

Re: Wix response to my inquiry on 51365 filter - 04/10/09 05:38 PM

 Originally Posted By: LoneRanger
Wix response:

Thank you for your inquiry.
At three gallons per minute, the WIX 51365 will produce 2 pounds or less of differential pressure. Differential pressure is the measured pressure drop across the filter assembly.


To add ... if what WIX said above is true with hot oil (say 5w-30 @ 200 F), and if the Subaru's oil pump is actually putting out 12 gpm at high RPM with the same hot oil, then the PSID across the filter is going to much higher than 2 psi, leaving less margin for loading etc, before bypass mode is reached. IMO, WIX needs to address the fact that the Subaru has a high volume oil system, and if their 8~11 psi bypass filter will suffice in all extremes of operating conditions (including loading factors). What do they really have to say about these conditions?
Posted by: Gary Allan

Re: Wix response to my inquiry on 51365 filter - 04/12/09 06:33 PM

 Quote:
What do they really have to say about these conditions?



I too would protest this egregious assault upon all the standards of sensible filtration self governess!!!



Psst! and I'd also ask them about cold start situations where the PSID will always be elevated due to low ..but relatively higher, volumes and the immutable conditions that will be present far more often.
Posted by: SuperBusa

Re: Wix response to my inquiry on 51365 filter - 04/12/09 08:43 PM

 Originally Posted By: Gary Allan
 Quote:
What do they really have to say about these conditions?


I too would protest this egregious assault upon all the standards of sensible filtration self governess!!!

Psst! and I'd also ask them about cold start situations where the PSID will always be elevated due to low ..but relatively higher, volumes and the immutable conditions that will be present far more often.


Ya mean like what I already said? Seems you're falling a little behind. ;\)

 Originally Posted By: SuperBusa

I'd email WIX back and pose those specific running conditions to see how he responds knowing their filter has a much lower bypass setting than the Subaru spec. There's no doubt that when the oil is nice and hot that 8~11 psi bypass would probably be OK ... but what about with cold thick oil at startup and during engine warm-up. That has been the focus of this whole discussion from page one.
Posted by: Gary Allan

Re: Wix response to my inquiry on 51365 filter - 04/12/09 11:15 PM

But you seem to default to that 12gpm thing. You know, the operational mode that no one really exists at for any length of time. Where's your chart (yes, I know where it is)?


JH: 20!
Posted by: SuperBusa

Re: Wix response to my inquiry on 51365 filter - 04/13/09 12:18 AM

 Originally Posted By: Gary Allan
But you seem to default to that 12gpm thing. You know, the operational mode that no one really exists at for any length of time. Where's your chart (yes, I know where it is)?

JH: 20!


There is no doubt that a HV oil system will have a bearing on the oil filter's design requirements; like the bypass setting which is the focus here ... even at full oil temperature at high RPM (yeah, some people do actually rev their engines near redline at times ). As said above ... even WIX understands that flow volume has a bearing on PSID. And why wouldn't they ... they actually design filters - what a concept.

You seem to forget the focus of this thread at times. Looks like straw grasping is about the only thing you have left to fall back on. ;\)

"JH: 20!" ... must be the brain cell filtering beta ratio for the 20 micron nerve synapse gat rating performance while you're wearing the tin foil hat.
Posted by: Gary Allan

Re: Wix response to my inquiry on 51365 filter - 04/13/09 12:35 AM

Well, keep in mind that volume is like viscosity. Any volume is low or high volume at some point in the process from zero to peak. Isn't a standard volume pump, on average the same as midspan in a HV pump (somewhere in there). It's just indexed at a lower engine speed ..which doesn't really mean much in that snap shot.

SB ..let's not get too far into our little tango here. I'm sure that Helen will be more than happy to end this permanently for both of us.

John Henry: "20!"
Posted by: SubLGT

Re: Subaru Oil Pump Specs as Relates to Filter Byp - 04/13/09 01:15 AM

 Originally Posted By: LoneRanger
WHAT?! I cannot believe the black Tokyo Roki filter did not meet standards. I think that SOA response is smoke and mirrors covering up for, as you indicated, a bean counting decision to go cheaper on an OE part. The Tokyo Roki filter was a quality piece. I wish whoever corresponded with SOA would have sent them a photo of the new Honeywell blue filter and the Tokyo Roki filter side by side, cut open. .........


They are probably referring to the white filter that came out around 2006 IIRC. It had problems with leaks.
Posted by: SuperBusa

Re: Wix response to my inquiry on 51365 filter - 04/13/09 01:32 AM

 Originally Posted By: Gary Allan
Well, keep in mind that volume is like viscosity. Any volume is low or high volume at some point in the process from zero to peak. Isn't a standard volume pump, on average the same as midspan in a HV pump (somewhere in there). It's just indexed at a lower engine speed ..which doesn't really mean much in that snap shot.


Well, in any case I'd really like to see WIX's viewpoint on using their 8 psi bypass filter on the high volume pumped Subaru if indeed it's putting out 12 gpm of hot oil. I'm betting the PSID with that much oil flow doesn't leave much headroom in their 8 psi filter bypass setting to account for much filter loading with use. And certainly at cold running conditions the 8 psi bypass valve is going to see a lot more action then the specified 23 psi bypass valve would - even though at cold temps the volume will way down from 12 gpm due to pump relief. That's been the take since page 1. I guess we need to hear it from WIX so we can see what the filter "gurus" think. Subaru has specified the higher bypass setting for a reason ... I'm sure WIX would understand why.
Posted by: Gary Allan

Re: Wix response to my inquiry on 51365 filter - 04/13/09 08:23 AM

 Quote:
Subaru has specified the higher bypass setting for a reason ... I'm sure WIX would understand why.
Sure. As does BMW/AUDI and any number of the Euro's. It is surprising that WIX doesn't offer it if it's deemed necessary. They do for just about any other engine peculiarity.


Can't get you to think "2 quarts of cold oil in excess of relief capability", huh?

So be it
Posted by: SuperBusa

Re: Wix response to my inquiry on 51365 filter - 04/13/09 01:22 PM

 Originally Posted By: Gary Allan
 Quote:
Subaru has specified the higher bypass setting for a reason ... I'm sure WIX would understand why.


Sure. As does BMW/AUDI and any number of the Euro's. It is surprising that WIX doesn't offer it if it's deemed necessary. They do for just about any other engine peculiarity.


So what’s different from a HV Euro car vs. a HV Japanese car oiling system? I think WIX hasn’t looked close enough at the flow specs of the Subaru and are specifying a filter that has too low a bypass setting. Now why would Subaru specify the 23 psi bypass and then someone like WIX spec a filter with only an 8 psi bypass? ... something doesn’t add up IMO.

We really need to hear WIX’s answer to why a 23 psi bypass is not required on a car that the manufacture specifies a 23 psi bypass setting.


 Originally Posted By: Gary Allan
Can't get you to think "2 quarts of cold oil in excess of relief capability", huh?

So be it


... we’ve gone round and round on that for how many pages now? Yeah, in most cases this is not an issue, and 8 ~ 11 psi bypass setting is probably just dandy. You gotta think outside the box on this one ... this is not your 1975 Econoline van with the straight 6-banger, low volume oiling system. Not all oiling systems will mirror the Econoline's oiling system.

Listen (as said a dozen times), the filter PSID and required filter bypass setting is entirely dependant on the oil volume flow rate and oil viscosity that goes through the filter during its operating conditions. If the Subaru’s oiling system is HV when hot, then it will also be relatively HV when the oil is cold and pump in relief mode. It may only put 3 ~ 4 gpm through the filter/engine flow path when cold as compared to 12 gpm when hot (under elevated RPM conditions), but that viscous oil at that lower flow rate may produce a pretty large filter PSID that requires the higher bypass setting (than 8 psi) to ensure most of it goes through the filter’s element until the oil warms up enough to lower the filter PSID.

If it was my car I wouldn’t run an 8 psi bypass filter when it really needs a 23 psi bypass filter that is clearly the factory spec. From all of your comments on this issue, you seem to endorse the use of the 8 psi filters on these Subarus with HV oiling systems ... hummm, I don’t think many owners will buy into your recommendation without some heavy duty backup material. I’d like to hear WIX's take if they ever address the issue clearly.
Posted by: Gary Allan

Re: Wix response to my inquiry on 51365 filter - 04/13/09 04:58 PM

 Quote:
So what’s different from a HV Euro car vs. a HV Japanese car oiling system?


None.

 Quote:
I think WIX hasn’t looked close enough at the flow specs of the Subaru and are specifying a filter that has too low a bypass setting. Now why would Subaru specify the 23 psi bypass and then someone like WIX spec a filter with only an 8 psi bypass? ... something doesn’t add up IMO.


You're right.

 Quote:
we’ve gone round and round on that for how many pages now?


Too many.

I'm not in disagreement with the reason for a 23psi bypass valve setting. We're at loggerheads over when it is needed most.

If you go back you'll see my reference to high volume, high pressure limit, Euro's that will spend a good part of their lives in relief (and therefore at elevated PSID -Thanks, Doug Hillary for putting that question to rest) requiring a abnormally high bypass valve rating (in excess of 30psi in many cases) JUST to assure that they aren't running a low beta bypass filter from 50 years ago in effective filtering.

 Quote:
You gotta think outside the box on this one


No, not in this case. Do you drive at higher rpm/volume levels for a higher % of your driving experience. Are you in steady state WOT more than you are in warm up? If you are, you're in a fringe marginal sliver of vehicle operation.
Posted by: SuperBusa

Re: Wix response to my inquiry on 51365 filter - 04/13/09 07:00 PM

 Originally Posted By: Gary Allan

 Originally Posted By: SB
we’ve gone round and round on that for how many pages now?


Too many.

I'm not in disagreement with the reason for a 23 psi bypass valve setting. We're at loggerheads over when it is needed most.



I made the following quote on page 1, almost a month ago. It was my 1st post in this thread. It’s still a true statement today after 17 pages of going in circles. The only reason you think “we’re at loggerheads over when it’s needed most” is because you won’t accepted the fact that using a filter with a much lower bypass setting would not be good because it would increase the bypass events and is a very questionable thing to do. If you owned a Subaru like this would you throw an 8 psi bypass filter on it knowing Subaru has specified a 23 psi bypass filter requirement for a reason? Is so, I’d really like to see the logic besides your thinking it’s really OK to run in bypass a lot more of the time instead of using the correct filter and hardly every running in filter bypass mode.

 Originally Posted By: SuperBusa on Page 1 of this thread

IMO, the filter's bypass is set higher because of the high volume oil pump.

So, it does look like the Subaru really needs a filter with a high bypass setting in order to ensure less time that the filter is in bypass mode. Obviously, this is more critical when the oil is cold with higher engine RPM. When the oil is near or at full operating temperature I'm sure the 23 psi bypass filter would never or hardly ever be in bypass. But, if you used a filter with a lower bypass there would certainly be more time in bypass mode IMO when the oil was cold and in the warm-up stage ... maybe even possibly when the oil is hot at max engine RPM.

Seems some of the bigger filter manufacture's like WIX or Purolator would come out with a filter with the high bypass setting for these Subarus ... as the filter manufactures are supposed to design their filters based on the vehicle's oil system specs.



 Originally Posted By: Gary Allan

If you go back you'll see my reference to high volume, high pressure limit, Euro's that will spend a good part of their lives in relief (and therefore at elevated PSID -Thanks, Doug Hillary for putting that question to rest) requiring a abnormally high bypass valve rating (in excess of 30psi in many cases) JUST to assure that they aren't running a low beta bypass filter from 50 years ago in effective filtering.


Yeah, well could you imagine how much time they would spend in bypass mode if they were using an 8 psi bypass on the filter instead of a filter “in excess of 30 psi in many cases” bypass setting on the filter? Why should a Subaru with a similar HV oiling system run an 8 psi filter when similar HV Euro cars need to run a 30 psi bypass filter? Your logic just goes right out the window at times.

 Originally Posted By: Gary Allan

 Originally Posted By: SB
You gotta think outside the box on this one.


No, not in this case. Do you drive at higher rpm/volume levels for a higher % of your driving experience. Are you in steady state WOT more than you are in warm up? If you are, you're in a fringe marginal sliver of vehicle operation.


Those are certainly possible operating conditions of the car, regardless of how much time is spend in what condition. The fact is, not everyone babies their cars all the time. The less time in filter bypass mode the better - anyone would agree with that. Certainly using an 8 psi bypass setting vs. a 23 psi bypass setting on the HV oil system is going to make a definate difference during some of these operating conditions. If it was my car I wouldn't want exessive filter bypass events ... but apparently you wouldn't care if it was your car - right? ;\)
Posted by: Gary Allan

Re: Wix response to my inquiry on 51365 filter - 04/14/09 02:46 AM

 Quote:
If you owned a Subaru like this would you throw an 8 psi bypass filter on it knowing Subaru has specified a 23 psi bypass filter requirement for a reason? Is so, I’d really like to see the logic besides your thinking it’s really OK to run in bypass a lot more of the time instead of using the correct filter and hardly every running in filter bypass mode.


I'm a amateur risk taker on a closed course. I use experimental 0w-10 oil in an antiquated push rod engine. If this was a non-turbo model, I'd run it in that too ..or at least start off with a 20 grade.

I wouldn't think twice about using a 8-11 bypass valve rated filter on that engine. I use one now on a HV setup ..with the smallest filter available in the 3/4-16 thread for automotive use.

It's not for everyone.

 Quote:
Yeah, well could you imagine how much time they would spend in bypass mode if they were using an 8 psi bypass on the filter instead of a filter “in excess of 30 psi in many cases” bypass setting on the filter? Why should a Subaru with a similar HV oiling system run an 8 psi filter when similar HV Euro cars need to run a 30 psi bypass filter? Your logic just goes right out the window at times.


What do you mean? The whole point of my perseverating over this is your obsession with high speed operation. I've just stated, as I have many times ..often with you arguing otherwise, that the most frequent elevated PSID event is during cold start. I don't think I have to go back and quote your arguments opposing this view. Since this is something that never occurred to you before entering into this discussion, you keep attempting to focus on the upper end of things. That's fine, I guess.

So ..we can count you among the believers that relief is the number one cause of elevated PSID?? Good. You're learning here \:\!

Tony Stark to Ms. Potts: Deflect it. Absorb it.

 Quote:
but apparently you wouldn't care if it was your car - right?


Life is one big managed risk, my friend. The whole reason for much of what I have done since joining the board is to dispel rhetorical fear factors. Many people state things out of some need for "rhetorical fear". "You'll shoot your eye out, kid!" type stuff. Very few of them have ever found out if the fear is rational or just something that they pulled out of their behind. People like to do that a good bit. They appear to like to precaution someone else to death. It happens no matter which way you go off of center in a very broad spectrum. You see it most clearly on viscosity debates. If you use a 20 grade and spec'd for a 20 grade, you're a sucker for CAFE and destroying your engine ..if you were in another country, you could use anything. If however, you were spec'd a 20 grade ..and wanted to use a 40 grade, even though it was spec'd in another country you would be destroying your engine. Both opinions are basically false, since neither of the supporters of either position would ever subject themselves to the other condition to find out. Hence, they're mostly talking out of their behind.

..but I want to KNOW. That's why when there is ever some [censored] footing around with marginal/fractional/couldawouldamighta opinion, I jump on it with TWO FEET and test the ice for breakage.


..but there is a racing section, you know
Posted by: SuperBusa

Re: Wix response to my inquiry on 51365 filter - 04/14/09 12:44 PM

 Originally Posted By: Gary Allan
 Originally Posted By: SB
If you owned a Subaru like this would you throw an 8 psi bypass filter on it knowing Subaru has specified a 23 psi bypass filter requirement for a reason? Is so, I’d really like to see the logic besides your thinking it’s really OK to run in bypass a lot more of the time instead of using the correct filter and hardly every running in filter bypass mode.


I wouldn't think twice about using a 8-11 bypass valve rated filter on that engine. I use one now on a HV setup ..with the smallest filter available in the 3/4-16 thread for automotive use.

It's not for everyone.


Does your “HV setup” potentially put out 12 gpm @ 5000 RPM? Do you keep the RPMs down low until the oil is nearly at full operating temperature? Do you change the filter before 5000 miles to ensure loading doesn’t increase PSID and take away already potentially small bypass headroom? Do you have an accurate delta pressure gauge across the filter that records it’s PSID at all times so you know when it's in bypass mode or not?

I’ve said before that an 8 psi bypass setting is probably borderline on the “OK side” when the oil is hot on a HV oil system ... but it really comes down to the actual flow volume and oil viscosity factors. Without doing an actual test with measurement instrumentation to see what the filter’s PSID would be in all operating conditions, you are just “assuming” it’s OK based on your past “experiences” with an Econoline van, which really have no scientific measure of merit if testing was not actually done directly on the HV system.


 Originally Posted By: Gary Allan
 Originally Posted By: SB
Yeah, well could you imagine how much time they would spend in bypass mode if they were using an 8 psi bypass on the filter instead of a filter bypass setting “in excess of 30 psi in many cases” on the filter? Why should a Subaru with a similar HV oiling system run an 8 psi filter when similar HV Euro cars need to run a 30 psi bypass filter? Your logic just goes right out the window at times.


What do you mean? The whole point of my perseverating over this is your obsession with high speed operation. I've just stated, as I have many times ..often with you arguing otherwise, that the most frequent elevated PSID event is during cold start. I don't think I have to go back and quote your arguments opposing this view. Since this is something that never occurred to you before entering into this discussion, you keep attempting to focus on the upper end of things. That's fine, I guess.


I’ve never argued that max PSID doesn’t occur at cold startup and enough PRM to get the pump into releif mode – I challenge you to go back and quote one time where I said otherwise. But you fail to also realize that there can be a significant PSID during high RPM usage with even warm or hot oil if the flow volumes are huge. There is a large, multi parametric operating envelope going on in an oiling system ... all operational boundaries need to be considered.

If Euro cars need a 30 psi bypass filter then don’t ya think that is so for a reason? Don’t you think a HV pumped Subaru could ever run at high RPMs at times, or be used like a Euro car? Are the oil filters sold for Subarus different in Europe than in the US because the filter manufacture thinks only grandpas drive Subarus in the USA ??


 Originally Posted By: Gary Allan
 Originally Posted By: SB
but apparently you wouldn't care if it was your car - right?


Life is one big managed risk, my friend. The whole reason for much of what I have done since joining the board is to dispel rhetorical fear factors. Many people state things out of some need for "rhetorical fear".


Whatever turns your crank. But why add to the risk when you can take away the risk by doing the right thing ... like using a filter with the correct bypass setting. Like I’ve said before, if I owned on of these Subarus I would not run the 8 psi bypass filter. I’d even rather run the so called “junk” OEM filter with the 23 psi bypass valve then run a so called “better filter” with the 8 psi bypass setting. I’m sure Subaru has qualified their OEM filters to meet all of their specifications, even if it is built by Fram.

So the bottom line from all this discussion is this:
Gary Allen - recommends going against Subaru’s specification and says it’s perfectly OK to use an 8 psi bypass filter.

Superbusa - recommends not using an 8 psi bypass filter, but instead using the best filter you can find that is has a 23 psi bypass valve as specified by and that meets Subaru’s specifications.

It comes down to the Subaru owners to decide what filter they want to use on their cars based on what has been discussed in this thread ... and of course from the technical inputs from WIX or any other filter manufactures that address this concern.
Posted by: Gary Allan

Re: Wix response to my inquiry on 51365 filter - 04/14/09 02:02 PM

 Quote:
Does your “HV setup” potentially put out 12 gpm @ 5000 RPM?


9gpm @ 3500

 Quote:
Do you keep the RPMs down low until the oil is nearly at full operating temperature?


The thing's like a diesel without the noise (well, some of it). It rarely sees above 2000-2500. You're in 3rd gear within 60ft in most cases.

 Quote:
Do you change the filter before 5000 miles to ensure loading doesn’t increase PSID and take away already potentially small bypass headroom?


Only if I'm changing oil like underwear (relatively speaking). Filters are used up to 20k. Loading effects, as I've clearly described in detail, are highly over rated in services that would also be conducive to longer OCI's.

 Quote:
Do you have an accurate delta pressure gauge across the filter that records it’s PSID at all times so you know when it's in bypass mode or not?


Not at the moment. Rather anal, wouldn't you say? Do you have a thermometer up your behind to constantly monitor if you have a fever?? I may do it again just to show you that it's the relief event that is responsible for elevated PSID ..but

 Quote:
I’ve said before that an 8 psi bypass setting is probably borderline on the “OK side” when the oil is hot on a HV oil system


It's probably great for the vast majority of sensible operation.

 Quote:
but it really comes down to the actual flow volume and oil viscosity factors.


Sure. Our dispute is "how much" and when it becomes a factor (the infamous chart).

 Quote:
Without doing an actual test with measurement instrumentation to see what the filter’s PSID would be in all operating conditions, you are just “assuming” it’s OK based on your past “experiences” with an Econoline van, which really have no scientific measure of merit if testing was not actually done directly on the HV system.


So, we can say that your postings are more valid due to 100% lack of any bona fide or amateur testing of any kind? Makes sense that your critique and input carries much more weight. Sorry, I must have wasted my time.

If "flow is flow" (I think one of us said this) ..and whatnot is whatnot, my observations can only be valid ..or not. They have to, just like a 20 weight is a 70 weight at some point in the warm up state, transition through those states that I observed, regardless of the ultimate volume potential of either system. A 12 gpm system has to, at some point, operate @ 6 gpm ..4 gpm ..1 gpm ..and so does a Mitsubishi 3.0. Even at 1/2 the output, it would have to look just like "half the output" (it was a 3.0 Mitsubishi btw ..and not an Econoline van).

 Quote:
I’ve never argued that max PSID doesn’t occur at cold startup and enough PRM to get the pump into releif mode – I challenge you to go back and quote one time where I said otherwise.


Perhaps not, but you did argue at length about how relief was not responsible for elevated PSID. Out of relief, regardless of viscosity, virtually no PSID (at least none compared to in relief situations). Even wix refers to an unqualified "2psid or less @ 3gpm". That's how much an issue they think it is. Not worth mentioning.

 Quote:
But you fail to also realize that there can be a significant PSID during high RPM usage with even warm or hot oil if the flow volumes are huge. There is a large, multi parametric operating envelope going on in an oiling system ... all operational boundaries need to be considered.


I don't think "fail" is the proper word here. It's got to be a rare instance where a filter can actually become part of the resistance equation. This is something you refuse to concede. It's, for the vast gross galactic majority of operational modes ..just not a factor. This is something that you consider above everything else ..even though it will be the least utilized aspect of the 23psi bypass setting. You love this end of it for some odd reason. That's fine.

 Quote:
If Euro cars need a 30 psi bypass filter then don’t ya think that is so for a reason?


Yes ..and I've stated them


 Quote:
Don’t you think a HV pumped Subaru could ever run at high RPMs at times, or be used like a Euro car?


Sure. Why not? A Euro car can be run like a Subaru too ..or a Chevette or a Camry ..or a 'Vette. What's your point? The point I think you're missing is that regardless of the ultimate capability of the chassis in question, it's going to be in warm up for the vast majority of its life if it's a daily driver. Much more of an issue than the rare instances of 100mph runs over all owners on average. That is, those used >20-30min are dwarfed by those <20-30min by a big margin. If they actually do get to stretch their legs, the feature would also be useful.

 Quote:
So the bottom line from all this discussion is this:
Gary Allen - recommends going against Subaru’s specification and says it’s perfectly OK to use an 8 psi bypass filter.



Not true. I said that I wouldn't worry about it. I think my disclaimer cleared this up (don't attempt this at home folks).

 Quote:
Superbusa - recommends not using an 8 psi bypass filter, but instead using the best filter you can find that is has a 23 psi bypass valve as specified by and that meets Subaru’s specifications.


..and Superbusa would be correct.
Posted by: SuperBusa

Re: Wix response to my inquiry on 51365 filter - 04/17/09 07:18 PM

http://www.subaruforester.org/vbulletin/f113/fram-2009-forester-part-number-conflicts-51958/

To hofcat’s post #6 in the thread above - go see page 2 of this thread, post #1411294 - 03/22/09 01:58 PM

That factor was addressed. Of course the resistance to oil flow (based on the media flow area and the media flow characteristics) will have a bearing on the required filter bypass setting. It think it was mentioned more than a few times in this thread.

Any more word back from WIX's Tech Dept on the bypass setting issue?
Posted by: LoneRanger

Re: Wix response to my inquiry on 51365 filter - 04/18/09 04:45 PM

 Originally Posted By: SuperBusa
Any more word back from WIX's Tech Dept on the bypass setting issue?


Well, I only tend to throw my line out where I feel confident that there are fish in the area, and since I don't see Wix as changing anything to cater to a very small, actually super small market (Enthusiasts who change own oil on a small sales volume brand of car), I have not yet asked further of them. I apologize for that.

I am using the Honeywell blue OE filter and intend to probably continue to use it until a suitable alternative with 23 psi bypass can be found. The Purolator 14460 (?) has the right bypass spec but the dimensions of the can are larger than OE, mainly diameter. And since the filter on my car is nestled in a cubby hole surrounded by exhaust plumbing within about an inch or so of a filter carrying OE diameter, going with a fatter filter is against my instinct. The exhaust piping has heat shields on it, but its still pretty close.


Posted by: 3oilmat1

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 04/22/09 02:54 PM

What in the [censored] does all this mean? I use a wix filter on a 2006 Subaru Tribeca. Am I ok?

Thanks
Posted by: LoneRanger

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 04/22/09 05:23 PM

Probably. I recommend the OE Subaru filter now, though.
Posted by: Gary Allan

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 04/22/09 06:14 PM

This is probably a byproduct of the turbo filter screen issue. Long term, and due to the nuances of the engine, it could lead to a clogged screen faster than those using the OEM filter.

There is, however, no downside to using the OEM for all applications.

There is no other source that I can find for a high rated bypass valve in that thread.
Posted by: webfors

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 05/05/09 11:03 AM

holy moly batman!! I can't believe I read this whole thread. My head hurts and I've learned very little due to my inability to decipher wtf you two are bickering about.

For everyone else, like me, here's the summary:

- use a filter with the right spec, or use the OEM subie filter. Tada! 9 pages of chinee down to one line.

I bought 10 Tokyo Roki black OEM filters last year on a group buy with my local subaru club. If you can still get them this is what I would recommend over any other filter for the H4.
Posted by: Hitzy

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 05/12/09 07:31 AM

I had a similar question to Wix with my 2008 Jeep Patriot (2.4L). The filter they list for this (57073) has a 28psi bypass valve, while the competitors have a 15psi bypass valve.
Here is their reply:
 Quote:
We contacted an engineer familiar with the design of this product.
What we found was that the psi rating on the bypass valve was
correct, but we understand how it could cause confusion. This
valve, and any other valve designed for this function by our company or any other, has a spectrum across which it performs. By this we mean that it does not function like a light switch, having either an"on or off" position. Rather, it has a variable degree of operation; in this case it begins to redirect the flow of oil
beginning around 8 pounds per square inch of pressure differential between the interior and the exterior of the elements body.

The rating that is published for this filter is representative of
when the bypass valve is at, or near its fully open position. With that said, the filter will perform as required by the system for which it is recommended.
Regards,
The Technical Service Team
Posted by: edhackett

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 05/12/09 11:45 AM

That isn't true in the case of a FRAM filter vs the FRAM built Subaru filter.

The FRAM with a 11 psi bypass took 4 pounds of force to initiate opening. The Subaru with a 23 psi bypass took 6 pounds.

The initial opening psi vs the fully open psi difference stated by the WIX representative clearly does not apply.

Ed
Posted by: SuperBusa

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 05/13/09 03:08 AM

 Originally Posted By: edhackett
That isn't true in the case of a FRAM filter vs the FRAM built Subaru filter.

The FRAM with a 11 psi bypass took 4 pounds of force to initiate opening. The Subaru with a 23 psi bypass took 6 pounds.

The initial opening psi vs the fully open psi difference stated by the WIX representative clearly does not apply.

Ed


I'm kind of surprised that there is such a large range between the initial opening pressure and full open pressure on the bypass valves. I would have thought it would go from closed to wide open in maybe 2 ~ 3 psi (ie, start to open at 20 psi and be fully open at 23 psi)
Posted by: Gary Allan

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 05/13/09 09:39 AM

I am surprised too. I would have thought it a variance in performance spec, not a designed range. That is, it would maintain 8-11 PSI.

The way they describe it, a spec of 8 would be difficult. I would think that all bypass valves would have a 3 psi range, but we know this is not so.
Posted by: SilverGGA

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 06/25/09 07:13 PM

Anyone tested whether the black Toyo Roki filter met 23psi bypass?
Posted by: 09rexwagon

Re: Subaru Oil Pump Specs as Relates to Filter Byp - 08/09/09 12:03 PM

 Originally Posted By: SilverGGA
Anyone tested whether the black Toyo Roki filter met 23psi bypass?
Yes I have. It is in the mid to high 18psi range when the valve begins to open. The Honeywell is dead on in the high 22s to mid 23s (I used 2 different filters with 2-3 trials on each and the average was 23.5psi). This confirms that the Tokyo Roki, did in fact, not meet Subaru specs and hence the change to the Honeywell....just wish they would have made them do a non-cardboard endcap.

What I will say about the Honeywell Subaru filter is it has much more pleats and what seems to be better sealing ABDV-to-cartridge and BV-to-cartridge junctions relative to an Orange Fram. Suffice it to say, I will be using the OEM one until my warranty runs out. I have contacted Wix, Bosch/Purolator, and Champion Labs with this concern. Hopefully if enough Subie owners voice this concern, they may have a new one for us in a few years.

I would use the Purolator XX14460 if it would fit my car though...it has the right bypass spec, but no ADBV, which at this point, I don't care about since it has next to no point on a vertical filter that is located as low as Subaru filters are located.
Posted by: Gary Allan

Re: Subaru Oil Pump Specs as Relates to Filter Byp - 08/09/09 12:39 PM

 Quote:
I don't care about since it has next to no point on a vertical filter that is located as low as Subaru filters are located.


I don't agree with this. A filter, as it impacts the circuit, is like a switchback or zig-zag line at a concession stand. It doesn't matter where in the "line" it's placed for the ultimate distance the oil has to travel (other than to it). The lower the filter the quicker the filter will be re-enveloped by the pump, but no difference in time to full engine envelopment should occur. What will happen to a filter without a ADBV that is very low relative to gallery level will be that it sees more back flow before breaking the siphon back to the sump.
Posted by: river_rat

Re: Subaru Oil Pump Specs as Relates to Filter Byp - 08/09/09 12:54 PM

I concur.
Posted by: 09rexwagon

Re: Subaru Oil Pump Specs as Relates to Filter Byp - 08/09/09 01:43 PM

If the filter is high relative to the sump, then siphoning is the biggest enemy. If the filter is low relative to the pump, the head above filter outlet is the enemy, in either case, the goal of the oil is to attain the lowest energy state which is in the sump. In an ideal world that ADBV would prevent this such that the totality of the oil passages would be completely full of oil all the time...even after the engine was stopped for hours, days, weeks. However, in practice it is shown that ADBVs do NOT do this. After a matter of hours, oil is getting past the ADBV and flowing OUT of the inlet (the circumferential holes in the filter that the ADBV rests on in a non-flowing state), back into the sump (whether the siphon from a high filter or the gravity of the oil column above a low filter is the driving force).
Posted by: Gary Allan

Re: Subaru Oil Pump Specs as Relates to Filter Byp - 08/09/09 04:22 PM

In a vertical orientation ..the higher the filter ... the less fluid (above it) needs to back flow to cavitate the center well. A few oz maybe. The lower the filter the higher the volume of fluid above it that must back flow through the filter by letting air relieve the siphon. Once the centerwell is exposed (it may create a vacuum before breaking the siphon) and air is common to both sides of the media ..there's nothing to flow.
Posted by: river_rat

Re: Subaru Oil Pump Specs as Relates to Filter Byp - 08/09/09 06:01 PM

That's right. Either way, the top of the oil column will seek sump level no matter where the filter is in the chain. Pressure above + vacuum below = the same delta P.
Until the oil level reaches a short distance down the center well and the remaining oil is trapped in the filter by self breaking the siphon effect.
Air from above the filter will not allow the filter to empty further, even if there were no ADBV.
Posted by: 09rexwagon

Re: Subaru Oil Pump Specs as Relates to Filter Byp - 08/09/09 06:13 PM

I absolutely did not insinuate that siphon below or pressure above can empty the filter completely of oil. Of course when things have drained to the point of (approximately) the top of the filter (on the outlet side), everything will hit a static equilibrium with the filter itself being full of oil (whether clean or dirty, it doesn't matter).

I think the last couple posts have completely missed the point.....WHY IS IT DRAINING PERIOD! If the ADBV did it's defined job, the siphon on the inlet side of the filter would clamp the ADBV shut and/or the head/pressure on the outlet side of the filter would push on the ADBV to secure it in place. And in this state, the oil should hypothetically stay 100% still....no draining into the sump (except for the small amount of oil between the sump and the filter inlet holes...just before the ADBV)...the 'column' of oil after the filter outlet should stay 100% full of OIL, not air. That is not case as we are finding....and this means at cold cranking it is taking a few revolutions to refill the oil passages. I'm really not concerned about this at all. My whole point in reference to ADBVs is that they don't (in all cases) perform the job that they are designed to perform to the utmost degree.
Posted by: Gary Allan

Re: Subaru Oil Pump Specs as Relates to Filter Byp - 08/09/09 07:47 PM

The last couple of posts are in response to you asserting that no ADBV is required since it sits so low. I assert that it is MORE essential due to the column of oil above it.
Posted by: 09rexwagon

Re: Subaru Oil Pump Specs as Relates to Filter Byp - 08/09/09 07:49 PM

 Originally Posted By: Gary Allan
The last couple of posts are in response to you asserting that no ADBV is required since it sits so low. I assert that it is MORE essential due to the column of oil above it.
But the ADBV doesn't hold the column of oil above it is my point to why an ADBV is not required.
Posted by: river_rat

Re: Subaru Oil Pump Specs as Relates to Filter Byp - 08/09/09 07:52 PM

 Originally Posted By: 09rexwagon
If the ADBV did it's defined job, the siphon on the inlet side of the filter would clamp the ADBV shut[...]My whole point in reference to ADBVs is that they don't (in all cases) perform the job that they are designed to perform to the utmost degree.

Sorry if I misunderstood you. I guess I should read more carefully. Yes, you are right, ADBVs are maybe 50% in reliabilty from my experience. I try to by the filters that seal air when I blow into the center hole. But neither is the seal between the threads on the nipple to the filter baseplate. Some oil may leak by there directly into the supply tube from the pump--depending on how long it sits.
Posted by: Gary Allan

Re: Subaru Oil Pump Specs as Relates to Filter Byp - 08/09/09 08:12 PM

 Originally Posted By: 09rexwagon
 Originally Posted By: Gary Allan
The last couple of posts are in response to you asserting that no ADBV is required since it sits so low. I assert that it is MORE essential due to the column of oil above it.
But the ADBV doesn't hold the column of oil above it is my point to why an ADBV is not required.


It's not required to HOLD a column of oil above it. It's supposed to SLOW/DELAY the mass backflushing event. The spec on ADBV's are to hold for "so long" ..or rather to take so long to drain ..pass xx amount of liquid ..whatever.

That is their primary purpose. That's why they're there. As I said, some manufacturers have found benefit in upgrading to silicon to limit this.
Posted by: river_rat

Re: Subaru Oil Pump Specs as Relates to Filter Byp - 08/09/09 10:34 PM

Ya. And I definitely want one that seals as good as spec no matter how my filter is mounted.
Posted by: marvinlee

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 04/14/10 09:24 PM

My 2010 Subaru Legacy Limited with the 3.6R engine came with a black Tokyo Roki filter. I ordered a spare oil filter of the same part number (also the manual's part number) and it, too, was a black Tokyo Roki oil filter of identical style and appearance. It weighs just a bit more, dry, than the crossed Purolator PureOne oil filter, also in dry, pre-use condition. I draw no great conclusions from any of this, other than that Subaru still uses some Tokyo Roki oil filters.
Posted by: SilverGGA

Re: Subaru Oil Pump Specs as Relates to Filter Byp - 04/14/10 09:56 PM

marvinlee: where did you order the replacement oil filter and what is the part number?

I think a lot of Subaru owners would like to know.

Originally Posted By: marvinlee
My 2010 Subaru Legacy Limited with the 3.6R engine came with a black Tokyo Roki filter. I ordered a spare oil filter of the same part number (also the manual's part number) and it, too, was a black Tokyo Roki oil filter of identical style and appearance. It weighs just a bit more, dry, than the crossed Purolator PureOne oil filter, also in dry, pre-use condition. I draw no great conclusions from any of this, other than that Subaru still uses some Tokyo Roki oil filters.
Posted by: Soobs

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 04/14/10 10:00 PM

Originally Posted By: marvinlee
My 2010 Subaru Legacy Limited with the 3.6R engine came with a black Tokyo Roki filter. I ordered a spare oil filter of the same part number (also the manual's part number) and it, too, was a black Tokyo Roki oil filter of identical style and appearance. It weighs just a bit more, dry, than the crossed Purolator PureOne oil filter, also in dry, pre-use condition. I draw no great conclusions from any of this, other than that Subaru still uses some Tokyo Roki oil filters.


The blue Honeywell filters are for H4 Subaru engines only. The H6 oil filter OEM is a Tokyo Roki.
Posted by: webfors

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 04/15/10 05:35 AM

Originally Posted By: Soobs
Originally Posted By: marvinlee
My 2010 Subaru Legacy Limited with the 3.6R engine came with a black Tokyo Roki filter. I ordered a spare oil filter of the same part number (also the manual's part number) and it, too, was a black Tokyo Roki oil filter of identical style and appearance. It weighs just a bit more, dry, than the crossed Purolator PureOne oil filter, also in dry, pre-use condition. I draw no great conclusions from any of this, other than that Subaru still uses some Tokyo Roki oil filters.


The blue Honeywell filters are for H4 Subaru engines only. The H6 oil filter OEM is a Tokyo Roki.


Is the H6 Tokyo Roki something that can be used on the H4?
Posted by: Soobs

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 04/15/10 12:23 PM

Originally Posted By: webfors
Originally Posted By: Soobs
Originally Posted By: marvinlee
My 2010 Subaru Legacy Limited with the 3.6R engine came with a black Tokyo Roki filter. I ordered a spare oil filter of the same part number (also the manual's part number) and it, too, was a black Tokyo Roki oil filter of identical style and appearance. It weighs just a bit more, dry, than the crossed Purolator PureOne oil filter, also in dry, pre-use condition. I draw no great conclusions from any of this, other than that Subaru still uses some Tokyo Roki oil filters.


The blue Honeywell filters are for H4 Subaru engines only. The H6 oil filter OEM is a Tokyo Roki.


Is the H6 Tokyo Roki something that can be used on the H4?


I really can't say for sure. I know it doesn't fit on the H4 Turbo due to clearance issues, but in the past you could put it on the H4 NA. The H6 filter also has the correct pressure relief of 23PSI.

You could call a dealership and find out if it works on the H4. (I think it does, but find out before you do it.)

The Honeywell filter really does a fine job though. Check out this UOA: http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=1857613#Post1857613
He uses the same setup as me. OEM air and oil filters with Chevron Supreme 5w30.
Posted by: TheMAN

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 04/15/10 01:13 PM

Originally Posted By: webfors
Originally Posted By: Soobs
Originally Posted By: marvinlee
My 2010 Subaru Legacy Limited with the 3.6R engine came with a black Tokyo Roki filter. I ordered a spare oil filter of the same part number (also the manual's part number) and it, too, was a black Tokyo Roki oil filter of identical style and appearance. It weighs just a bit more, dry, than the crossed Purolator PureOne oil filter, also in dry, pre-use condition. I draw no great conclusions from any of this, other than that Subaru still uses some Tokyo Roki oil filters.


The blue Honeywell filters are for H4 Subaru engines only. The H6 oil filter OEM is a Tokyo Roki.


Is the H6 Tokyo Roki something that can be used on the H4?

I know you already saw this, but this is for others to see:
http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=1855050&page=3

short answer is no, you don't want to put the H6 filter in the 4 cyl
Posted by: SilverGGA

Re: Subaru Oil Pump Specs as Relates to Filter Byp - 04/16/10 04:05 PM

How about the 2.0 WRX Turbo? Not that I am going to use it in my car...
Posted by: TheMAN

Re: Subaru Oil Pump Specs as Relates to Filter Byp - 04/17/10 02:25 PM

like I said... no
read my post in the other thread which explains why
Posted by: Jackfortune

Re: Filter Bypass psi/Mazda replacment for Subaru - 10/24/10 10:24 AM

Check out this thread on LegacyGT.com:
http://legacygt.com/forums/showthread.php?t=147113

For those of you looking for the 23 psi bypass filter for a Subaru, follow the thread to the 2009 Mazda RX8 oil filter comments. Should be an exact fit for Subarus, with a higher can capacity (and more filter media?). Filter #N3R114302. My apologies if this info is already in this thread somewhere.
Posted by: webfors

Re: Filter Bypass psi/Mazda replacment for Subaru - 10/24/10 11:42 AM

Yeah, that's a good option. The Tokyo Roki's are made very well! Only concern is having the filter close to the exhaust headers... they get *very* hot. However, that's more a theoretical concern than a practical one.
Posted by: ZeeOSix

Re: Filter Bypass psi/Mazda replacment for Subaru - 10/24/10 01:55 PM

Originally Posted By: Jackfortune
Check out this thread on LegacyGT.com:
http://legacygt.com/forums/showthread.php?t=147113


From the spec sheet someone posted on that link, the oil pump's pressure relief setting is 156.6 psi ... Wow! shocked
Posted by: webfors

Re: Filter Bypass psi/Mazda replacment for Subaru - 10/24/10 04:15 PM

Originally Posted By: ZeeOSix
Originally Posted By: Jackfortune
Check out this thread on LegacyGT.com:
http://legacygt.com/forums/showthread.php?t=147113


From the spec sheet someone posted on that link, the oil pump's pressure relief setting is 156.6 psi ... Wow! shocked


Look closer, it's 20-26 psi grin
Posted by: ZeeOSix

Re: Filter Bypass psi/Mazda replacment for Subaru - 10/24/10 04:59 PM

Originally Posted By: webfors
Originally Posted By: ZeeOSix
Originally Posted By: Jackfortune
Check out this thread on LegacyGT.com:
http://legacygt.com/forums/showthread.php?t=147113


From the spec sheet someone posted on that link, the oil pump's pressure relief setting is 156.6 psi ... Wow! shocked


Look closer, it's 20-26 psi grin


Look closer ... I said oil pump's pressure relief setting. There is a difference, I'm well aware of that. grin
Posted by: webfors

Re: Filter Bypass psi/Mazda replacment for Subaru - 10/24/10 08:33 PM

Originally Posted By: ZeeOSix
Originally Posted By: webfors
Originally Posted By: ZeeOSix
Originally Posted By: Jackfortune
Check out this thread on LegacyGT.com:
http://legacygt.com/forums/showthread.php?t=147113


From the spec sheet someone posted on that link, the oil pump's pressure relief setting is 156.6 psi ... Wow! shocked


Look closer, it's 20-26 psi grin


Look closer ... I said oil pump's pressure relief setting. There is a difference, I'm well aware of that. grin


ahh... I read to fast grin
Posted by: ZeeOSix

Re: Filter Bypass psi/Mazda replacment for Subaru - 10/25/10 02:46 AM

Originally Posted By: webfors

ahh... I read to fast grin


No problem ... I sometimes do too. wink With the oil pump able to put a maximum pressure of 156.6 PSI on the oiling system before the pumps starts dumping back to the sump, it's no wonder they have some insane GPM spec on their oil system.

The Subaru's oil system is not something that falls in the "norm" of most street cars.
Posted by: fishbone

Re: Subaru Oil Pump Specs as Relates to Filter Bypass - 10/26/10 11:32 AM

Just when I thought I found an oil filter to stick with, you guys go casting doubt over it smile Been using PureOnes for a while now, even did a UOA over winter and everything came back fine, except for some high lead (45ppm in 4K miles when traditionally it has been around 12). Relief valve on the PureOnes is 14-18PSI, OEM is 20-26. I've had UOAs come back with contaminants in oil on the OEM filters when I used to live out in rural area, that's why I switched.
Insight? I'm inclined to think if it ain't broke don't fix it and continue to use PL14612 especially since it's taller than OEM.
I had contacted Purolator, a product engineer said it's fine and not to worry about it, some people said it may be cause of failed turbos due to the oil line screen filter getting clogged because the filter was in bypass mode for too long/when it should not have been.
Posted by: SubLGT

Re: Filter Bypass psi/Mazda replacment for Subaru - 03/18/11 05:01 PM

Originally Posted By: ZeeOSix
............With the oil pump able to put a maximum pressure of 156.6 PSI on the oiling system before the pumps starts dumping back to the sump, it's no wonder they have some insane GPM spec on their oil system.

The Subaru's oil system is not something that falls in the "norm" of most street cars.


That spec is for a Mazda rotary, not a Subaru. The Subaru relief valve is set at 85psi.
Posted by: ZeeOSix

Re: Filter Bypass psi/Mazda replacment for Subaru - 03/18/11 05:39 PM

Originally Posted By: SubLGT
Originally Posted By: ZeeOSix
............With the oil pump able to put a maximum pressure of 156.6 PSI on the oiling system before the pumps starts dumping back to the sump, it's no wonder they have some insane GPM spec on their oil system.

The Subaru's oil system is not something that falls in the "norm" of most street cars.


That spec is for a Mazda rotary, not a Subaru. The Subaru relief valve is set at 85psi.


Yes, you are correct on the RX-8 spec. That's some pretty high oil pressure. shocked
Posted by: stenerson

Re: Filter Bypass psi/Mazda replacment for Subaru - 11/01/13 11:41 AM

I was gonna post question about filter for my new used 2005 outback. (it has new motor) Did a search and got this interesting thread. Good to know about this psi spec. I get the oem filters for about 6 bucks with washer, I guess I'll stick with that.
Posted by: Izb

Re: Filter Bypass psi/Mazda replacment for Subaru - 01/25/14 06:31 AM

I am afraid, that a lot of previous media (using by Purolator, Champ, Fram, Mobil, Amsoil, RP) ... can be destroyed under high pressure like 23-28 psi...

And this is the main reason of existing only few filters with high settings of bypass valve...

p.s.
For example, why Pure One PL14615 (announced 3 years ago!) is not in the market since then?
Posted by: ZeeOSix

Re: Filter Bypass psi/Mazda replacment for Subaru - 01/25/14 03:24 PM

Originally Posted By: Izb
I am afraid, that a lot of previous media (using by Purolator, Champ, Fram, Mobil, Amsoil, RP) ... can be destroyed under high pressure like 23-28 psi...

And this is the main reason of existing only few filters with high settings of bypass valve...

p.s.
For example, why Pure One PL14615 (announced 3 years ago!) is not in the market since then?


How do you know the media in the PL14615 is any different than the media in any other PureOne? And how do you know what filter brands would have media that would be destroyed with 23-28 PSID across the media?

A PureOne PL14006 with only 105 sq-in of media area has a low 5 PSID with 12 GPM of hot 5W-30 oil flowing through it.

http://www.bobistheoilguy.com/forums/ubb...451#Post1619451

The Subaru engines don't flow much beyond that, so if Subaru is specifying a 23 PSI bypass valve on their OEM filter, then it's for massive bypass headroom for various reasons (ie, filter loading, expected high engine RPM with cold thick oil, owner's using thicker oils than specified, etc), and/or the filter itself is pretty flow restrictive and has much more than 5 PSID with hot oil at 12 GPM.
Posted by: tojo1968

Re: Filter Bypass psi/Mazda replacment for Subaru - 01/27/14 08:12 AM

Originally Posted By: stenerson
I was gonna post question about filter for my new used 2005 outback. (it has new motor) Did a search and got this interesting thread. Good to know about this psi spec. I get the oem filters for about 6 bucks with washer, I guess I'll stick with that.

I've used OEM on my 06 Forester since new with no problems. BTW, check with your local dealerships and see if you can order parts on their website. I get filter/washer for $4.54+tax from my local dealer because I order and pay for them online.