What is more important flow or filtration??

[Gary Allan]

Originally Posted By: friendly_jacek
Originally Posted By: BuickGN
Yep, oil pressure before the filter will go up but with the positive displacement oil pump, flow will be the same.

Remember, there is a bypass there too whether it's on the engine or in the filter.

Don't assume that better filtration means less flow. This may be true of the conventional cellulose filters but not the synthetic media Amsoil and Royal Purple filters.


Not quite. Higher pressure before filter will force more oil to bypass valve after the oil pump and less to the bearings.

Mobil 1 and PureOne are more restrictive. There are many studies that document that. Not sure Amsoil, but possible.


Yes, 'quite'. Everyone somehow thinks that the pressure on the other side of the filter is substantially lower. It's not.

No one has the slightest inkling of "back pressure" that make the filter mostly invisible under all but a few conditions. It's beyond comprehension for most. This is very difficult to convey.

 

[SuperBusa]

Originally Posted By: Gary Allan
Originally Posted By: friendly_jacek
Originally Posted By: BuickGN
Yep, oil pressure before the filter will go up but with the positive displacement oil pump, flow will be the same.

Remember, there is a bypass there too whether it's on the engine or in the filter.

Don't assume that better filtration means less flow. This may be true of the conventional cellulose filters but not the synthetic media Amsoil and Royal Purple filters.


Not quite. Higher pressure before filter will force more oil to bypass valve after the oil pump and less to the bearings.

Mobil 1 and PureOne are more restrictive. There are many studies that document that. Not sure Amsoil, but possible.


Yes, 'quite'. Everyone somehow thinks that the pressure on the other side of the filter is substantially lower. It's not.

No one has the slightest inkling of "back pressure" that make the filter mostly invisible under all but a few conditions. It's beyond comprehension for most. This is very difficult to convey.



It may not be "substantially" lower .. but it IS lower due to flow going through it - that is what the PSID is. It's a fact and law of fluid flow dynamics. "Substantially" is an unqualified term here. But read on before you get all wound up ...

And as pointed out many times in these types of discussions, the filter's flow resistance is ONLY an issue when the oil pump is at pressure relief. If the pump is not in pressure relief, then ALL the oil volume goes through the filter (due to positive displacement pump) regardless of how much PSID it creates in the filter.

Of course, if that PSID is at or beyond the bypass valve setting in the filter, then the bypass valve will open.

A more restrictive filter will cause the oil pump to run closer to pressure relief (if it isn't already) than a less restricted one (under the same operating conditions). Once the oil pump is in pressure relief, then a more restrictive filter will cause less engine oil pressure due to the larger PSID across the filter's media.

 

[Gary Allan]

Nope, Soup...not bitin' ..same story ..different episode for you.

 

[Steve S]

Probably [in general] any difference in oil filter will never be noticed. Oil filters aren't super critical as is the air filter and seal of the intake.

 

[OVERKILL]

Originally Posted By: SuperBusa
Originally Posted By: Gary Allan
Originally Posted By: friendly_jacek
Originally Posted By: BuickGN
Yep, oil pressure before the filter will go up but with the positive displacement oil pump, flow will be the same.

Remember, there is a bypass there too whether it's on the engine or in the filter.

Don't assume that better filtration means less flow. This may be true of the conventional cellulose filters but not the synthetic media Amsoil and Royal Purple filters.


Not quite. Higher pressure before filter will force more oil to bypass valve after the oil pump and less to the bearings.

Mobil 1 and PureOne are more restrictive. There are many studies that document that. Not sure Amsoil, but possible.


Yes, 'quite'. Everyone somehow thinks that the pressure on the other side of the filter is substantially lower. It's not.

No one has the slightest inkling of "back pressure" that make the filter mostly invisible under all but a few conditions. It's beyond comprehension for most. This is very difficult to convey.



It may not be "substantially" lower .. but it IS lower due to flow going through it - that is what the PSID is. It's a fact and law of fluid flow dynamics. "Substantially" is an unqualified term here. But read on before you get all wound up ...

And as pointed out many times in these types of discussions, the filter's flow resistance is ONLY an issue when the oil pump is at pressure relief. If the pump is not in pressure relief, then ALL the oil volume goes through the filter (due to positive displacement pump) regardless of how much PSID it creates in the filter.

Of course, if that PSID is at or beyond the bypass valve setting in the filter, then the bypass valve will open.

A more restrictive filter will cause the oil pump to run closer to pressure relief (if it isn't already) than a less restricted one (under the same operating conditions). Once the oil pump is in pressure relief, then a more restrictive filter will cause less engine oil pressure due to the larger PSID across the filter's media.


If your engine's bearings flow oil like a toilet flows water maybe....... Ford's Modular engines (for example) run somewhat tight bearing clearances due to the solidity of the bottom-end. Subsequently, oil pressure is VERY high compared to other engines. The old Cleveland engines used to run nutty oil pressure too. This pressure is a function of the resistance of the lubrication system, NOT the oil filter. The filter is all but transparent in these situations because the resistance comes from the ENGINE.

The engine would have to have a VERY high flowing oil system for the filter, under normal circumstances, with warm oil, to be any sort of real restriction.


EDIT: And before this turns into ANOTHER 'busa and Gary thread where some Unicorn example of a Subaru engine gets brought up with an oil gallery system that flows like Niagra falls and an oil pump that moves more volume than the bilge pumps on the USS Ronald Reagan, we are talking about NORMAL engines here, where the biggest restriction in the lube system IS the engine.

 

[SuperBusa]

Originally Posted By: Gary Allan
Nope, Soup...not bitin' ..same story ..different episode for you.


That's OK ... you have no bite left to give anyway.

 

[SuperBusa]

Originally Posted By: OVERK1LL
Originally Posted By: SuperBusa

It may not be "substantially" lower .. but it IS lower due to flow going through it - that is what the PSID is. It's a fact and law of fluid flow dynamics. "Substantially" is an unqualified term here. But read on before you get all wound up ...

And as pointed out many times in these types of discussions, the filter's flow resistance is ONLY an issue when the oil pump is at pressure relief. If the pump is not in pressure relief, then ALL the oil volume goes through the filter (due to positive displacement pump) regardless of how much PSID it creates in the filter.

Of course, if that PSID is at or beyond the bypass valve setting in the filter, then the bypass valve will open.

A more restrictive filter will cause the oil pump to run closer to pressure relief (if it isn't already) than a less restricted one (under the same operating conditions). Once the oil pump is in pressure relief, then a more restrictive filter will cause less engine oil pressure due to the larger PSID across the filter's media.


If your engine's bearings flow oil like a toilet flows water maybe....... Ford's Modular engines (for example) run somewhat tight bearing clearances due to the solidity of the bottom-end. Subsequently, oil pressure is VERY high compared to other engines. The old Cleveland engines used to run nutty oil pressure too. This pressure is a function of the resistance of the lubrication system, NOT the oil filter. The filter is all but transparent in these situations because the resistance comes from the ENGINE.


It really doesn't matter how much the engine flows or doesn't flow. The fact is that anytime the pump is in pressure relief mode, a more restrictive filter will decrease the flow volume to the engine to some degree.

The filter does add restriction to the flow going to the engine when the pump providing max supply pressure. What's the difference in flow with a constant 80 psi source between two systems with different flow resistance? ... one system being more restrictive than the other due to say a partially clogged filter? Anyone can answer that correctly.

Yes, the MAJORITY of the resistance comes from the engine's resistance ... BUT, the filter also ADDS to that TOTAL resistance. The flow circuit being through the filter then the engine is in SERIES. So if the oil filter is restrictive, it obviously makes the TOTAL flow restriction higher.

Originally Posted By: OVERK1LL
The engine would have to have a VERY high flowing oil system for the filter, under normal circumstances, with warm oil, to be any sort of real restriction.


Yes ... agreed. It would need high flow and/or high viscosity oil flowing. Subaru's pump spec claims 12 gpm. I'm sure some big hi-pro V8 put out at least 8 gpm. Not every car is "NORMAL" on the road that flows 3 gpm at redline.

My Z06 sees 70 psi at the engine inlet sensor (after filter) with hot oil at 200+ degrees at high RPM. Not everyone drives around like a grandma either. Some people actually rev up their engines to get max HP out of them quite often.

Everything I've said on this subject holds true. A filter will cause LESS oil flow to the engine if it's more restrictive AND the oil pump is in pressure relief mode. In a case like that, the oil pump just diverts more excess flow back through the pump's pressure relief valve because it can't be forced down a more restrictive path at the same volume. It's elementary fluids here.

 

[d00df00d]

Originally Posted By: SuperBusa
It may not be "substantially" lower .. but it IS lower

If it's not substantially lower, why do we care?

It sounds like you're making a theoretical argument. That is fine, and I have to imagine you are right. Gary is making a different argument, though. He's not saying the effect doesn't exist, but that it doesn't matter. What's the problem?

 

[SuperBusa]

Originally Posted By: d00df00d
Originally Posted By: SuperBusa
It may not be "substantially" lower .. but it IS lower

If it's not substantially lower, why do we care?


Who says that a pretty restrictive filter would cause no ill effects? IMO, nobody could say one way or the other. Imagine a hi-pro engine with substantial oil flow at high RPM and running relatively thick oil. Maybe the filter being ran reduces the engine's supply pressure by say 6 or 8 psi at high RPM use compared to a free flowing filter under those conditions. Fact is, when the engine is at full tilt is when it needs the most oil flow. Will it hurt the engine to have slightly less oil flow when it needs the most? ... maybe, maybe not. But if I had the knowledge and choice in a filter that flows better, then I'd run it to be safe. Why do you think there exists "racing filters"? Yeah, they don't filter quite as good (although some almost do) ... but they flow like mad and have a very small PSID at higher flow compared to the "average" filter for grandma's Oldsmobile.

Originally Posted By: d00df00d
It sounds like you're making a theoretical argument. That is fine, and I have to imagine you are right. Gary is making a different argument, though. He's not saying the effect doesn't exist, but that it doesn't matter. What's the problem?


Probably 95% of discussions on this board are "theoretical" in nature. If it wasn't for theoretical discussion here, this board (or about all on the internet) wouldn't exist. Actually, I believe Gary thinks the PSID in a filter disappears entirely for some magical reason ... anyone with some engineering and fluid flow knowledge would know otherwise.

Why do you think Bob and others on this board came up with their own home made experiments to measure and determine pressure drop differences among different filters? ... just for something to pass some time away?

 

[d00df00d]

Let me make sure I understand.

IF you're using a heavy oil;
IF you have a restrictive filter; and
IF your engine is revving very high;

then the filter might have a significant adverse effect on oil pressure, and the pump might not be able to compensate. Is that a fair summary of what you just said?

 

[SuperBusa]

Originally Posted By: d00df00d
Let me make sure I understand.

IF you're using a heavy oil;
IF you have a restrictive filter; and
IF your engine is revving very high;

then the filter might have a significant adverse effect on oil pressure, and the pump might not be able to compensate. Is that a fair summary of what you just said?


To clarify, those are mutually exclusive factors. There are many things involved in the dynamics of an oiling system ... that's why many people can't grasp the whole picture.

The oil pump does not "compensate". All an oil pump does is supply oil volume to a fixed flow path. The more restictive the flow path is, the more pressure it takes to force the same oil volume through it. The oil pump and filter bypass valve don't "work in concert" as some believe. They operate independantly of each other. One does not affect the other.

If the pressure required to force X GPM exceeds the pump's pressure relief setting, then that is the max pressure and max corresponding flow associtated with that fixed flow resistance (ie, the serial flow path of filter/engine circuit). If you start increasing the flow resistance of the filter when the pump is in pressure relief mode, then you start choking oil flow to the engine. Fluids 101.

The other side of the equation is the design of the oil filter itself. If you installed a filter that was relatively restrictive, and had a relatively low bypass setting, then it could do two things based on its flow characteristics and bypass valve setting: a) go into bypass mode much easier and more often, and b) cause a higher pressure drop at higher flow rates thereby reducing the oil flow volume to the engine.

Does it happen all the time? ... no. Can it happen? ... yes. Will it harm an engine ... maybe.

 

[Kruse]

Originally Posted By: SuperBusa

To clarify, those are mutually exclusive factors. There are many things involved in the dynamics of an oiling system ... that's why many people can't grasp the whole picture.


I've got one of these on a 4.6 FoMoCo product right now. I've cut one open and this is a wonderfully built filter. I don't think the media is restrictive because there is just so much media, as compared to a lot of other manufacturers. It's also got the silicone ADBV and a PTFE impregnated gasket for easy removal. (Okay, that might be marketing hype, I dunno)

If you are worried that this filter is too restrictive, what filter do you run that you are not losing sleep over? (Just curious)

 

[d00df00d]

Originally Posted By: SuperBusa
Does it happen all the time? ... no. Can it happen? ... yes. Will it harm an engine ... maybe.

Okay. So, IF it happens, it MIGHT harm an engine. Right?

 

[Gary Allan]

Again, regardless of what oil you're using. Regardless of the oil volume flowing...there can be no alteration to flow WHATSOEVER if the pump isn't in relief. Hence regardless of the filter chosen ..at high output ..at "hot oil" high volume ..at 9999 rpm ..until that relief valve on the pump opens ..the pressure is merely ...merely a "product" of that flow.

Now sure, when you can actually tax the flow potential of the filter ..then one comparative filter may produce more PSID than another. But to apply this very obscure and niche situation to anything outside of it ....without clearly qualifying it as totally out of the vast galactic commonality of filterdom ..is just being intellectually disingenuous.

Bob's test established a inlet pressure of 70lb and read the PSID. If he had set the downstream pressure instead, then he would have been reasonably assured of the same visc just due to room temp ..and therefore identical flow rates. 70f+/- SAE 30 weight should be at the same flow rate if put through the same static resistance (the engine used). Instead he used voltmeters and whatnot to show the same amp load (iirc) on the electric motor that drove the divorced oil pump. A pump in relief would be "spinning its tires" and probably attenuate at a given amp load through a fixed resistance. They're moving the same amount of fluid.

 

[SuperBusa]

Originally Posted By: Kruse
Originally Posted By: SuperBusa

To clarify, those are mutually exclusive factors. There are many things involved in the dynamics of an oiling system ... that's why many people can't grasp the whole picture.


I've got one of these on a 4.6 FoMoCo product right now. I've cut one open and this is a wonderfully built filter. I don't think the media is restrictive because there is just so much media, as compared to a lot of other manufacturers. It's also got the silicone ADBV and a PTFE impregnated gasket for easy removal. (Okay, that might be marketing hype, I dunno)

If you are worried that this filter is too restrictive, what filter do you run that you are not losing sleep over? (Just curious)


If you read this whole thread, you will realize that I think the PureONE flows up there with the best flowing filters out there.

 

[SuperBusa]

Originally Posted By: d00df00d
Originally Posted By: SuperBusa
Does it happen all the time? ... no. Can it happen? ... yes. Will it harm an engine ... maybe.

Okay. So, IF it happens, it MIGHT harm an engine. Right?


You got it ... take it as you please, but those are the possibilities and not out of question. Just because grandma's Econline van doesn't fit the profile doesn't mean someone else's turboed Subaru or Z06 Vette doesn't.

 

[SuperBusa]

Originally Posted By: Gary Allan
Again, regardless of what oil you're using. Regardless of the oil volume flowing...there can be no alteration to flow WHATSOEVER if the pump isn't in relief. Hence regardless of the filter chosen ..at high output ..at "hot oil" high volume ..at 9999 rpm ..until that relief valve on the pump opens ..the pressure is merely ...merely a "product" of that flow.


Yeah ... we all know that IF the pump is NOT in pressure relief, then ALL the flow volume goes throught the filter/engine. I've said it dozens of times. The only time the flow restiction of the filter comes into play is then the pump is producing max oil pressure in its relief mode.

Originally Posted By: Gary Allan
Now sure, when you can actually tax the flow potential of the filter ..then one comparative filter may produce more PSID than another. But to apply this very obscure and niche situation to anything outside of it ....without clearly qualifying it as totally out of the vast galactic commonality of filterdom ..is just being intellectually disingenuous.


The fact is ... it CAN and DOES happen is certain cases. It's not "obsure" to realize that there ARE cars on the road that can tax an oil filter. My Vette creates ~ 5 or 6 PSID on a NAPA Gold filter at high RPM ... with HOT oil. I believe the bypass valve is set to 8 - 11 psi on the NAPA Gold filters, so you can see it's operating within a few psi of opening the bypass valve with 200+ deg F oil flow. If that filter started loading up, you can bet the bypass valve would be cracking open every time the engine was revved above 4000 RPM.

Originally Posted By: Gary Allan
Bob's test established a inlet pressure of 70lb and read the PSID. If he had set the downstream pressure instead, then he would have been reasonably assured of the same visc just due to room temp ..and therefore identical flow rates. 70f+/- SAE 30 weight should be at the same flow rate if put through the same static resistance (the engine used). Instead he used voltmeters and whatnot to show the same amp load (iirc) on the electric motor that drove the divorced oil pump. A pump in relief would be "spinning its tires" and probably attenuate at a given amp load through a fixed resistance. They're moving the same amount of fluid.


If you go back and read that 30+ page thread, you will realize they later put a globe valve downstream to limit the flow (like an engine would create backpressure), and if I'm not mistaken later on actually used an old engine to produce the flow backpressure.

No matter how it was done, and it's been done by others beside Bob, the fact is the testing gave a relative comparison of the flow performance difference between the filters tested. Just like the flow vs. PSID graph produced by ACDelco (posted in this thread), you can see there are obvious differences in the PSID produced in different filters under the same test flow conditions.

 

[7777]

Both are important to me and also the least start up noise,I'm still looking for that filter.

 

[Gary Allan]

Quote:
No matter how it was done, and it's been done by others beside Bob, the fact is the testing gave a relative comparison of the flow performance difference between the filters tested. Just like the flow vs. PSID graph produced by ACDelco (posted in this thread), you can see there are obvious differences in the PSID produced in different filters under the same test flow conditions.



Sure, it does, but that testing, and your infamous flow chart aren't giving an accurate picture of how compressed that difference is in real time. Right now you're implying that Bob's later alterations altered the fundamental error that he used supplied pressure as opposed to downstream pressure to establish equal flows. That is, you're attempting to validate it ..even though you will have to rationally admit that it's flawed.

Your charts are equally misleading in that no such flows could ever be attained without a MUCH LARGER downstream restriction dwarfing the alleged PSID figures ..that is, compressing them into insignificance at any sensible flow. The flows cited are outlandish in any rational sense of being demonstrative. Yet you seem to neglect to point this out in your assertions. Glenn Beck, at least, starts off by saying "Now I'm not saying this!! I wouldn't say that ..but" ..then proceeds to say exactly what he just discounted.

 

[SuperBusa]

Originally Posted By: Gary Allan
Quote:
No matter how it was done, and it's been done by others beside Bob, the fact is the testing gave a relative comparison of the flow performance difference between the filters tested. Just like the flow vs. PSID graph produced by ACDelco (posted in this thread), you can see there are obvious differences in the PSID produced in different filters under the same test flow conditions.


Sure, it does, but that testing, and your infamous flow chart aren't giving an accurate picture of how compressed that difference is in real time. Right now you're implying that Bob's later alterations altered the fundamental error that he used supplied pressure as opposed to downstream pressure to establish equal flows. That is, you're attempting to validate it ..even though you will have to rationally admit that it's flawed.


When Bob's tests were refined to try and simulate more realistic flow rates, the data still showed what filters were more restrictive than others. Useful date none the less, regardless if the flow and viscosity was exactly the same as a real life engine senario.

Originally Posted By: Gary Allan
Your charts are equally misleading in that no such flows could ever be attained without a MUCH LARGER downstream restriction dwarfing the alleged PSID figures ..that is, compressing them into insignificance at any sensible flow. The flows cited are outlandish in any rational sense of being demonstrative. Yet you seem to neglect to point this out in your assertions. Glenn Beck, at least, starts off by saying "Now I'm not saying this!! I wouldn't say that ..but" ..then proceeds to say exactly what he just discounted.


I've said many times that the testing is COMPARITIVE. You are not reading/comprehending what I'm saying ... you need to understand that I'm NOT claiming these are real flow conditions. I've qualified the chart many times. What you and othters need to realize is that this is a comparative measurement. So what if the flows are all "unrealisticly high". The fact is, all were tested under the same flow conditions so the PSIDs are also relative comparisons.

When you look at this graph, one can conclude that M1 and FRAM Toughgaurd flow worse than the others, and ACDelco Utragaurd flows the best. The four remaining in the middle ground all flow basically the same in any real world flow situation.

Of course its obvious that the lower the GPM flow the less difference there is between all these filters. But if an engine only flowed 2 GPM with this viscosity of oil, then there is a noticable difference in PSID produced. The M1 and FRAM Toughguard would probably be running in bypass mode in that situation. That is the basic usefullness of this kind of data. Beyond that, you can't get much more out of it.