BOBISTHEOILGUY FILTER TESTS

[Roger]

My figures might be off a bit from the camera angle, but it looks like the percent pressure drop is roughly as follows:

Amsoil: 40 vs 34 = -15%
Mobil 1: 40 vs 30 = -25%
K&N: 42 vs 36 = -14.5%
Fram: 40 vs 38 = -9.5%
Bosch: 40 vs 30 = -25%
Napa Silver: 38 vs 32 = -15.7%
Fram TG: 40 vs 22 = -30%
Napa Gold: 40 vs 32 = -20%
Pure1 40 vs 28 = -30%
Purolator+ : 40 vs 32 = -20%
Motorcraft: 40 vs 24 = -40%
STP: 40 vs 34 = -15%

Fascinating, but I'm not sure I see the trend this early into the testing.

[ March 27, 2003, 07:53 PM: Message edited by: Roger ]

 

[Patman]

One thing I wonder about the cold oil though, wouldn't most of the filters be in bypass mode with the thicker cold oil?

 

[digitaldrifter91]

yea the filter should be in bypass mode due to cold oil. these tests are only a start. only when we get a warm oil test is when we will find out the true suddle differnces.

 

[BOBISTHEOILGUY]

I have a question... So if the by pass valves where engaged due to the oil being too cold(imo it's not), wouldn't that mean that the oil flow would be equal on the inside as well as the outside? By pass means passing by the filtration media and going around it with out restriction, so why would there be a drop across these filters if by pass was open? Just something to think about...

 

[digitaldrifter91]

perhaps there will be a little resistance from the anti drain back valve, but not as much to put that much of a pressure drop. but u do have a point, but doesnt cold oil flow less than warm oil? if so, the oil is going through the filter at a slower pace than if u were to warm it...maybe thats where the pressure drop is comming from. though we can only guess. i was told and learned that when oil is cold it goes through bypass...hehe guess ill throw that out of my head.

i wish i had the resources to make a clear oil filter or get one made and actually watch the oil filter in progress...now that would be really nice.

 

[cryptokid]

bob, the bypass valve only opens at a certain pressure differental.

and while its open, it needs a pressure differental to stay open.

 

[digitaldrifter91]

humm thought about something, the fram had the least drop, maybe its bypass valve was open becuase it had what 3psi drop and thas it...

yea in essence the psi would be the same, but u still have resistance with that anti drain back valve and the holes.

but gee i can only speculate

btw bob thanks for sharing ur research with us.

 

[Ken2]

Bob, there is always pressure drop, or there is no flow. Flow always has to be from higher pressure to lower pressure.

In the oil filters, let's say that the bypass is built for operation of 8 psi differential. This means that with something like a 7 psi differential between the inlet and the outlet the valve begins to open and at maybe 9 psid the valve is fully open. There is still this 7~9 psid pressure drop through the filter and forcing some oil through the media. If the pressure drop falls below our 7 psid, the bypass valve will close and all the oil will pass through the media.

These filters are not designed to filter cold oil. Too thick. I'd suggest finding a liquid with a cold viscosity equal to 180°F SAE 30 oil...maybe kerosine + 10% 30 wt or whatever works out.


Ken

 

[BOBISTHEOILGUY]

See, the interesting point I'm making is that the bypass valve, many say it's open when in fact there is no evidence of this at this time. What is evident is that we need to take into account the resistance of the antidrain back valve having to be over come by the oil pump which would increase the oil pump pressure on the inlet side, and then then the drop on the outlet side... how much pressure is needed to over come the anti drainback valve? Frams anti drainback valve may not have much resistance thus allowing better flow unlike mobils. Point is, at this time I think it is premature to suggest the bypass valve is open at any given moment. What I'd expect to see is when the pressure is increased on the inlet side, the outlet would be low mementaraly, then shoot up to or near the inlet pressure, then settle back down within the range of the by pass pressure 8-12lbs.

I'm still working on a way to watch the bypass so we can actually see this, but not sure yet.

As for the heated oil, first, this oil temp'd out today at 77degrees, IMO, not cold enough to engage the bypass due to thick oil. We do have a barrel heater, which will heat up the bucket of oil to 400 degrees, but we are only going to set it up to 200 then re run these tests with the hot oil. This has got to be systematic, so bear with me as I work on this in stages. I am going to continue to use the 10w30 multi viscosity as it is the most common we use so I want to see just how a regular motor oil is going to perform as if in an engine that's why no straight wt oil will be used in this test at this time.

After we have completed all the basic tests then we'll do some out of the norm things and see what happens. One thing I'm going to do is at the next oil change, I'm going to keep my old filter, with mileage documented, run against the new filter and see just how much flow is lost over that set miles compared to the new one. This could in effect tell us the basic life span of a filter based on mileage. Just another one of those ideas.

 

[digitaldrifter91]

well said. yea frams anti draw back valve on some filters that have them are just rubber...the other stuff like purolator is i think silicone. its more affective in keeping oil going back to slump.

you know what bob, i got some plexi glass in the back yard. i am giong to see if i can cut open a filter and then shove that plastic on the shell so i can see what realyl happends. i bet i am nto going to have sucess but gee if it does work im guessing it will be benificial to all of us. i used to do alot of work with plexi glass.

ill probably just cut the filter, and then try to replicate the volume of the shell and mount it on the filter. then seal it with JB weld. ill put the filter on my friends car (haha festiva) and see whats up. if i do it right i may see it happen.

...as u can tell im bored. well time for work.

keep up the good work.

 

[Cressida]

I just did a cross for the Motorcraft FL400s at the Bladwin site


It crosses to the B243 which list a bypass of 8 PSI. Therefore it would seem that the Motorcraft - and probably many of the other filters that Bob has tested are in FULL bypass.

No wonder my Motorcraft filter never seems to show any signs of being dirty.

This is going to get very interesting indeed.

[ March 27, 2003, 09:59 PM: Message edited by: BOBISTHEOILGUY ]

 

[Greg]

here's an idea, cut open the fram extra and tough guards that you have there bob (same ones you tested) to see if there are any discernable defects or differences in manufacture visible.

 

[digitaldrifter91]

outch. imagine all that time with full bypass. my z is in full bypass now. when i start up its at like 55 psi. but later it is down to 30. though its a fram and its going through auto rx. i wish i can know for sure.

if i run a higher bypass wont that be better? hehe in a way it wouldnt cause if my filter is cloggin up then i wont get oil..but then it always gets filterd cause it wont go through bypass as much.

this is extensive research. hehe.

quote:

---

Originally posted by Cressida:
I just did a cross for the Motorcraft FL400s at the Bladwin site


It crosses to the B243 which list a bypass of 8 PSI. Therefore it would seem that the Motorcraft - and probably many of the other filters that Bob has tested are in FULL bypass.

No wonder my Motorcraft filter never seems to show any signs of being dirty.

This is going to get very interesting indeed.

---

 

[llbts1]

Nice work. I wonder though if all of this flow concern is necessary. Each engine has different flow requirements doesn't it? It was explained to me on this forum that engines are designed with a filter requiremnet. The mfg designs a filter for that motor. Then the aftermarket people get ahold of a oem filter, tear it apart and make a better? mouse trap. So as long as the filter provides the required flow per engine mfg, Why would this be of concern? I would think as long as your filter of choice meets flow requiremnets, your next big concern would be max filtration. Set me straight folks, I'm just trying to learn. Thanks, Larry

 

[digitaldrifter91]

lol good point..every engine is differnt and really its going to only benifit the engine that bob has. but i think we can have an idea of how that filter is. then we find out what psi our cars work at and make a decision from there. there are some of us who need high flow, and some dont. so its give or take. im going to use bobs findings and try and find a filter that balances flow with filtration according to his reasearch. but bob started a revolution LOL

 

[Patman]

I've got another suggestion. How about taking one of the lower cost filters and buying another one to see if it produces the same results as the first one?

I'd especially be interested in seeing if a different Fram filter would produce those same results, or if the first one was a lucky fluke. Maybe the first Fram flows so well since the oil might be leaking past those pesky cardboard endcaps!

 

[dickwells]

Lets all keep in mind that the pressure relief valve only functions when there is differential across the filter. The overall pressure in the system has nothing to do with it. Secondly, aren't there filters with no relief valve? Built for the engines that have a presssure relief valve built in? If so then by getting the same filter in both versions maybe somthing about the valve performance could be extrapolated. Bob-Your idea about testing used filters is inspirational..ATTABOY.

[ March 28, 2003, 09:01 AM: Message edited by: dickwells ]

 

[Greg]

quote:

---

Originally posted by digitaldrifter91:
well said. yea frams anti draw back valve on some filters that have them are just rubber...the other stuff like purolator is i think silicone. its more affective in keeping oil going back to slump.

you know what bob, i got some plexi glass in the back yard. i am giong to see if i can cut open a filter and then shove that plastic on the shell so i can see what realyl happends. i bet i am nto going to have sucess but gee if it does work im guessing it will be benificial to all of us. i used to do alot of work with plexi glass.

ill probably just cut the filter, and then try to replicate the volume of the shell and mount it on the filter. then seal it with JB weld. ill put the filter on my friends car (haha festiva) and see whats up. if i do it right i may see it happen.

...as u can tell im bored. well time for work.

keep up the good work.

---

the alliedsignal fram PH6811 has a silicone anti-drainback valve. go look for it.

 

[Patman]

quote:

---

Originally posted by dickwells:
Lets all keep in mind that the pressure relief valve only functions when there is differential across the filter. The overall pressure in the system has nothing to do with it. Secondly, aren't there filters with no relief valve? Built for the engines that have a presssure relief valve built in?

---

Yes, if Bob could somehow fit a filter on there that is meant for a GM engine, these filters have no bypass valve.

So the AC Delco PF44, PF47, PF52, PF58, PF59, PF25, PF35, PF1218 all come to mind, and their cross references, as I know for sure none of these filters use a bypass valve.

 

[VaderSS]

I agree that the bypass valve is an issue here. The bypass is a big unknown so it should probably be eliminated from the circuit, unless it can be positively shown that it is open or closed.

I agree with above proposals that the bypass valve is variable in nature, opening just enough to let the excess flow bypass the filter, and depending on the quality of the mechanism, there may never be a pressure spike to show it has opened or closed.

I also agree with above opinions that true flow should be measured. This could be as simple as stabilising motor rpm and temperature, then diverting the outlet flow into a known volume and measuring the time to fill it, or more complex like a rotameter or some other flow meter.

I don't feel that it is necessary to hold flow to some constant for all tests, as long as the flow is measured and recorded, and the inlet pressure is held constant across the board.

It also probably matters little what the flow is as long as it is near some "real world" number, whether that number is for a 5.7L V8 or a 1.2L I4, or somewhere in between.

Thank you Bob and Joe!!