Oil Filter Flow Rate vs. Filtering Efficiency - Can You Have Both ?

[wdn]

In the Subaru Outback, the service manuals says the oil pump in the FB25 engine puts out 14.5 GPM at 6,000 rpm.

 

[Ignatius]

The Ultra had a delta P of 16.9. PSI. That is what the graph shows. The bypass valve on the Ultra opens at 13 PSI. Therefore the Ultra would go into bypass with a delta P of 17 PSI. The oil pump on a Subaru operates at 12.7 GPM. Is that not a normal street car? At just over 10 GPM flow the delta P across the Ultra exceeds the PSI threshold of its bypass valve.

You are not factoring in differential pressure, you are free to believe me or not but based on my near extensive research on the subject the unsaturated media flow rate of the Ultra effectively cuts the PSID in half as far as delta P across the media. By my estimation you would need to use this filter beyond two consecutive oil change intervals before the bypass boogeyman factor would come into play.

Being a bypass valve enthusiast myself I am using a Wix 57055 or Napa Gold 7055 on my 2021 Outback at every oil change and just not worrying about it.

 

[Job]

The Royal Purple is the light blue line and had the most restriction. The Ultra is the dark blue and in in the middle of the pack virtually identical to a Boss. I guess I don't understand what the problem here is with the Ultra. The only question I have is how consistent one test is to the filter I would buy. Actually for me it wouldn't matter at all I change filters often and drive easy all the time to save gas. Unless it's in ev mode then it's free to me driving.

 

[circuitsmith]

I have wondered with oil filters if you can have superior flow rate - yet retain a high filtering efficiency

A bigger filter element (more surface area) will do it, if there's room.

 

[4WD]

Well: for me I see these things
(I have used every brand in the test)
Royal Purple is very expensive and restrictive
ACD leaked at seam
Wix XP has poor micron cut and PRV leaked
The Boss costs more than Fram XG here …

 

[IndyFan]

Well: for me I see these things
(I have used every brand in the test)
Royal Purple is very expensive and restrictive
ACD leaked at seam
Wix XP has poor micron cut and PRV leaked
The Boss costs more than Fram XG here …

So like it appears for you, I keep coming back to the Fram XG. Or at least when my stash of clearance priced Mobil 1 filters runs out. Btw, I think the Mobil 1 filters would have been interesting to have in this conversation. But in my applications UOA's seem to indicate a pattern of slightly less efficient filtering than the Fram XG. But still very good. I'd be curious how the flow compared, but as others have said, it doesn't really matter if their performance is within the envelope.

In my application, which is a cartridge for the Pentastar, I have not measured the area of the pleats between the M1, Purolator (Mopar) and XG, but they look like they would be similar. The Fram is by far held together better. Not even close, in terms of construction.

 

[ZeeOSix]

The Ultra had a delta P of 16.9. PSI. That is what the graph shows. The bypass valve on the Ultra opens at 13 PSI. Therefore the Ultra would go into bypass with a delta P of 17 PSI. The oil pump on a Subaru operates at 12.7 GPM. Is that not a normal street car? At just over 10 GPM flow the delta P across the Ultra exceeds the PSI threshold of its bypass valve.

Go back and look more carefully. The Royal Purple was over ~17 PSI at 13 GPM. The Ultra was ~13.5 PSI at 13 GPM.

 

[ZeeOSix]

ZeeOSix you said so yourself on this forum two months ago:

If delta P PSI exceeds bypass valve PSI, that triggers the bypass valve to open. The graph showed delta P of the Ultra was not only much higher than the other filter tested, more importantly it was higher than the Ultra’s own bypass valve threshold. And that was for a brand new filter.

Look at the colors ... or better yet, look at the video and the tabulated test data.

 

[ZeeOSix]

In the Subaru Outback, the service manuals says the oil pump in the FB25 engine puts out 14.5 GPM at 6,000 rpm.

Yeah, it does ... but go look at other vehicle service manuals and you'll see that hardly any stock street car oil pumps put that much out. My Z06 oil pump only puts out around 8~9 GPM at redline. Subaru high volume oil pumps are not the "norm". One reason Subaru specifies a high filter bypass setting.

 

[4WD]

So like it appears for you, I keep coming back to the Fram XG. Or at least when my stash of clearance priced Mobil 1 filters runs out. Btw, I think the Mobil 1 filters would have been interesting to have in this conversation. But in my applications UOA's seem to indicate a pattern of slightly less efficient filtering than the Fram XG. But still very good. I'd be curious how the flow compared, but as others have said, it doesn't really matter if their performance is within the envelope.

In my application, which is a cartridge for the Pentastar, I have not measured the area of the pleats between the M1, Purolator (Mopar) and XG, but they look like they would be similar. The Fram is by far held together better. Not even close, in terms of construction.

Yes, will go back to XG10575 … already have an XG in the JLU based on what Carbon Steel Power Stroke Grinch recommended … plan on running 2X 5K OCI based on what Blue Oval recommended

 

[ZeeOSix]

… plan on running 2X 5K OCI based on what Blue Oval recommended

Thought he was going with 3X OCIs.

 

[4WD]

So like it appears for you, I keep coming back to the Fram XG. Or at least when my stash of clearance priced Mobil 1 filters runs out. Btw, I think the Mobil 1 filters would have been interesting to have in this conversation. But in my applications UOA's seem to indicate a pattern of slightly less efficient filtering than the Fram XG. But still very good. I'd be curious how the flow compared, but as others have said, it doesn't really matter if their performance is within the envelope.

In my application, which is a cartridge for the Pentastar, I have not measured the area of the pleats between the M1, Purolator (Mopar) and XG, but they look like they would be similar. The Fram is by far held together better. Not even close, in terms of construction.

Yes … have used many M1 filters - one up to 16k … most 5k to 10k … built like a tank …

 

[IveBeenRued]

The Ultra had a delta P of 16.9. PSI. That is what the graph shows. The bypass valve on the Ultra opens at 13 PSI. Therefore the Ultra would go into bypass with a delta P of 17 PSI. The oil pump on a Subaru operates at 12.7 GPM. Is that not a normal street car? At just over 10 GPM flow the delta P across the Ultra exceeds the PSI threshold of its bypass valve.

Dumb question, where are you seeing that the Ultra had a delta P of 16.9? The highest that I’m seeing the video indicates 320 inches of water at 49.6 lpm which equates to 11.84 PSI at 13.1 gallons per minute according to all the online calculators that I’m finding.

 

[ZeeOSix]

enchroma.com

 

[Job]

So this ends the question of why Subaru uses a higher bypass valve setting since these unused filters bump up against the standard bypass setting at Subaru max pump volumes. When the filter gets clogged or the oil thick, the pressure goes up even more. Oh, I guess this was said sort of already.

 

[ChrisD46]

In practical applications of your typical OCI of 5K miles the Fram Ultra would not be tested much ?

 

[4WD]

In practical applications of your typical OCI of 5K miles the Fram Ultra would not be tested much ?

When GM put out the memo on higher PRV settings … and Fram responded with an upgrade … I noted then that I would give the stores time to purge old stock. Looking like they have so I will go back to the XG10575 and shorten my OCI’s to 5k using the filter twice …

 

[Job]

In practical applications of your typical OCI of 5K miles the Fram Ultra would not be tested much ?

I don't think it would be tested much unless you are racing the engine to the max rpm according to the chart. It depends how much dirt your engine is putting into the filter, cut it open at 5k, if it looks clogged than replace it at 5k. Looks clogged isn't very scientific but that's when judgement, like on so many other things, comes in. For me, my error in judgement will always be on the conservative side, change filter when in doubt.

 

[wdn]

Go back and look more carefully. The Royal Purple was over ~17 PSI at 13 GPM. The Ultra was ~13.5 PSI at 13 GPM.

OK maybe I am a bit colorblind. I do not know what is the bypass setting on Royal Purple is iether, but it is 13 PSI on Fram. That means under normal operating conditions, at least on a Subaru Outback which is14.7 GPM, the Ultra will be in bypass because at anything over 13 GPM the Ultra will be in bypass.

 

[wdn]

I don't think it would be tested much unless you are racing the engine to the max rpm according to the chart. It depends how much dirt your engine is putting into the filter, cut it open at 5k, if it looks clogged than replace it at 5k. Looks clogged isn't very scientific but that's when judgement, like on so many other things, comes in. For me, my error in judgement will always be on the conservative side, change filter when in doubt.

In a Subaru it would more than be tested, a brand new FRAM Ultra would be in bypass at well below max RPM. Operating anywhere under redline is normal operating conditions, else Subaru would have lowered redline to say, 4,000 RPM. It would be interesting to see how the delta P of these filters increases after 5,000 or 10,000 miles in service but it is only going to increase as the filter loads up, not to decrease.

You were right though this test result should settle the matter why Subaru sets its bypass spec high, to 23 PSI or 27 PSI. Now maybe we should look for filters that say they are “recommended” for Subaru but whose filters have bypass PSI set so low that a brand new filter of theirs easily goes into bypass.