Subaru Oil Pump Specs as Relates to Filter Bypass

[SubLGT]

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.

 

[SuperBusa]

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.

 

[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.


Can't get you to think "2 quarts of cold oil in excess of relief capability", huh?

So be it

 

[SuperBusa]

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.

 

[Gary Allan]

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.

 

[SuperBusa]

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?

 

[Gary Allan]

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

 

[SuperBusa]

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.

 

[Gary Allan]

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
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.

 

[SuperBusa]

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?

 

[LoneRanger]

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.

 

[3oilmat1]

What in the [censored] does all this mean? I use a wix filter on a 2006 Subaru Tribeca. Am I ok?

Thanks

 

[LoneRanger]

Probably. I recommend the OE Subaru filter now, though.

 

[Gary Allan]

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.

 

[webfors]

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 *** 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.

 

[Hitzy]

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

 

[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

 

[SuperBusa]

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)

 

[Gary Allan]

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.

 

[SilverGGA]

Anyone tested whether the black Toyo Roki filter met 23psi bypass?