Any studies of differential pressure versus time?

[uart]

It's interesting to see some people changing their filters only every second oil change and others going to the other extreme and changing it mid OCI.

I just wish we had a bit more data to guide us as to how long a typical filter can actually operate before the differential pressure starts to rise due to clogging of the media. Has anyone seen any studies of this. Differential pressure versus time (or versus miles driven) for an OEM filter in a typical passenger car application?

 

[HerrStig]

If filters were 20 bucks each (give the enviroweenies time) a lot more attention would be paid to measurements of this kind.

 

[uart]

Originally Posted By: HerrStig
If filters were 20 bucks each (give the enviroweenies time) a lot more attention would be paid to measurements of this kind.

The Toyota dealer was charging me $23 for the little OEM filter that's made in Thailand. Dealer prices are usually a rip off in Australia. Luckily I can get aftermarket replacements that are better for around 8 to 9 dollars.

Still, regardless of cost it would be interesting to know. You can definitely save yourself some time and effort in only changing a filter every second OCI (or by avoiding changing it mid OCI on a long drain interval).

 

[ARCOgraphite]

My car (FIT) gets noisy 1/2 through the OCI with wix or champ or factory. I would love to leave my filter on for 6-7K miles. The Subaur doesnt apper to be affected and uses an excellent Tokyo-Roki unit (though they just went to a universal + smaller form P/N)

 

[JOD]

I think we're all waiting for Jim Allen to rig up some more gauges on his truck, say OP senders right before and after the filter, then start logging some data. In the name of Science! Until then, we're in the dark.

I agree, it's a good question. Modern engines run pretty clean, so I'm taking it on faith and my eyeball restriction gauge after cutting the filters open that the increase is minimal on a well-maintained engine. I would also imagine that filters with a more 3-dimensional synthetic media will reduce restriction at a slower rate, but that's pure speculation on my part.

 

[uart]

Before I posted here I googled to try and find info about this. Interestingly I found some info on heavy machinery. For example the following is an excerpt from a Caterpillar marine engine operator manual.

Quote:
Engine Oil Filter Differential Pressure
Observe the oil filter differential pressure frequently during engine operation.

This gauge indicates the difference in pressure between the inlet side and the outlet side of the engine oil filters. As the oil filter elements become plugged, oil filter differential pressure will increase. The nominal oil filter differential pressure during normal engine operation is approximately 9 psi. Replace the oil filter elements when the oil filter differential pressure reaches 15 psi.

 

[getnpsi]

When used oil is sent out we are always checking the oil. The only time we even think of filtering is when the silicon goes way up. I'd love to see a UOA of the same oil back to back and the user go from a $$ media filter to a supertech or other bargain piece. Again the variables are going to be that many more miles on the air filter and all components. My guess if you have no air leaks and have been diligent everywhere, you can definitely skip filter changing and/or go way cheap on them. Even if in bypass if there is less to catch, there is less to catch.

 

[ZeeOSix]

Maybe someday car manufacture's will include a delta-P sensor across the oil filter to help monitor filter loading. Wouldn't be very hard to do. But the car manufacturer's are saying if you change the filter per the service schedule there shouldn't be any worries about the filter loading up enough to make the delta-P high and the filter going in to bypass.

 

[Texan4Life]

is there a gauge that measures differential pressure? That way you don't have to have 2 gauges to figure out the differential pressure.

like maybe it has 2 pressure lines and then can show show just the diff. pressure psi?

 

[Texan4Life]

Originally Posted By: Texan4Life
is there a gauge that measures differential pressure? That way you don't have to have 2 gauges to figure out the differential pressure.

like maybe it has 2 pressure lines and then can show show just the diff. pressure psi?


yep they do... http://www.differentialpressure.com/

 

[440Magnum]

Originally Posted By: Texan4Life
is there a gauge that measures differential pressure? That way you don't have to have 2 gauges to figure out the differential pressure.

like maybe it has 2 pressure lines and then can show show just the diff. pressure psi?


This is where I get to be a smart-aleck and say that MOST gauges read differential pressure- the difference between the fluid under test and atmospheric pressure ;-)

For those who don't know how a mechanical pressure gauge works, the 'Bourdon' subsection of this article explains and has good pictures.


But yes, there are dedicated differential-pressure gauges available.

In order to know if the differential pressure measured is a problem for a particular engine or not, you will also need to know the bypass pressure of the specified oil filter. So long as the differential pressure is below the bypass pressure AND engine oil pressure isn't down a few PSI, then all is good. In practice, I would observe the initial differential pressure and then see how it changes through the course of an OCI. And you also kinda have to be consistent with the RPM and temp where you make your observation, because differential pressure will be VERY different between hot and cold oil, and fairly different between idle and 3000 RPM.

 

[Jim Allen]

Originally Posted By: JOD
I think we're all waiting for Jim Allen to rig up some more gauges on his truck, say OP senders right before and after the filter, then start logging some data. In the name of Science! Until then, we're in the dark.



Odd you should say that now since I just ordered the equipment to do that. I grew faint at the cost of the dedicated differential pressure gauges, so I will be running two identical Isspro pressure gauges (the very accurate stepper types) side by side. I have a filter base with ports on both sides of the filter, so I will be able to observe the differences in the readings. Among the research projects I will undertake:

-observe bypass events on cold starts, both for duration and frequency

-observe the frequency of bypass events in all situations

-test different filters for starting and ending Delta P. This could possibly also offer some insight on the most or least restrictive types and brands of filters... at least those that will fit my 5.4L Ford.

-observe the increase in Delta P over time and determine the right time to change the filter due to loading

 

[440Magnum]

Originally Posted By: Jim Allen

-test different filters for starting and ending Delta P. This could possibly also offer some insight on the most or least restrictive types and brands of filters... at least those that will fit my 5.4L Ford.


If you're taking suggestions, I'd love to see several of the synthetic- media filters up front. My vote for first on the hot seat would be a Fram Ultra because of the (assumed) big bang for the buck. Others I'd like to see are the Royal Purple, Purolator Synthetic, and of course a good old Puorlator Classic or Wix as a baseline. I'd kinda like to see a P1 also, just because I've gotten real curious about how tightly the filter end plates fit within its can, and wonder if that is a non-filter-media related restriction point on the P1 in particular.

 

[3311]

Originally Posted By: Jim Allen
Originally Posted By: JOD
I think we're all waiting for Jim Allen to rig up some more gauges on his truck, say OP senders right before and after the filter, then start logging some data. In the name of Science! Until then, we're in the dark.



Odd you should say that now since I just ordered the equipment to do that. I grew faint at the cost of the dedicated differential pressure gauges, so I will be running two identical Isspro pressure gauges (the very accurate stepper types) side by side. I have a filter base with ports on both sides of the filter, so I will be able to observe the differences in the readings. Among the research projects I will undertake:

-observe bypass events on cold starts, both for duration and frequency

-observe the frequency of bypass events in all situations

-test different filters for starting and ending Delta P. This could possibly also offer some insight on the most or least restrictive types and brands of filters... at least those that will fit my 5.4L Ford.

-observe the increase in Delta P over time and determine the right time to change the filter due to loading
I can't wait to see your results!! I would second the classic as a basline and go from there.

 

[JOD]

Originally Posted By: Jim Allen

Odd you should say that now since I just ordered the equipment to do that. I grew faint at the cost of the dedicated differential pressure gauges, so I will be running two identical Isspro pressure gauges (the very accurate stepper types) side by side. I have a filter base with ports on both sides of the filter, so I will be able to observe the differences in the readings.


I new we could count on you!

If you want to test PSID on a well-used Napa Platinum for your application, just let me know and I'll send it your way after my next oil change.

 

[Jim Allen]

I will test a variety of filters. Immediately upon installing the new gauge, I will be testing the well used P1 on there now that has about 12K on it. After that, I'll have to think. I'm running some other tests right now so it may be a while before I can do "the great filter comparo"... but I will do that at some point.

Sorry JOB, ain't no way I'm putting somebody's old filter to "swap spit" with my truck. Remember Seinfeld and his "boys" when Kramer wanted to borrow an item of clothing... ( : < ).

 

[JOD]

"Ford Freestyle Filter Free to Good Home, gently used..."

Seriously, I'm curious to see how this shakes out. My honest guess is that in well-maintained engines, the degradation over the life of the filter is going to be a lot less than folks would think; but your method is better than guessing.

 

[ZeeOSix]

Originally Posted By: 440Magnum
I'd kinda like to see a P1 also, just because I've gotten real curious about how tightly the filter end plates fit within its can, and wonder if that is a non-filter-media related restriction point on the P1 in particular.


PureOnes don't seem to be very restrictive. Test data from Purolator:

http://www.bobistheoilguy.com/forums/ubb...451#Post1619451

 

[Texan4Life]

Originally Posted By: 3311
Originally Posted By: Jim Allen
Originally Posted By: JOD
I think we're all waiting for Jim Allen to rig up some more gauges on his truck, say OP senders right before and after the filter, then start logging some data. In the name of Science! Until then, we're in the dark.



Odd you should say that now since I just ordered the equipment to do that. I grew faint at the cost of the dedicated differential pressure gauges, so I will be running two identical Isspro pressure gauges (the very accurate stepper types) side by side. I have a filter base with ports on both sides of the filter, so I will be able to observe the differences in the readings. Among the research projects I will undertake:

-observe bypass events on cold starts, both for duration and frequency

-observe the frequency of bypass events in all situations

-test different filters for starting and ending Delta P. This could possibly also offer some insight on the most or least restrictive types and brands of filters... at least those that will fit my 5.4L Ford.

-observe the increase in Delta P over time and determine the right time to change the filter due to loading
I can't wait to see your results!! I would second the classic as a basline and go from there.


+1 ! Jim for the BITOG win!

 

[440Magnum]

Originally Posted By: ZeeOSix
Originally Posted By: 440Magnum
I'd kinda like to see a P1 also, just because I've gotten real curious about how tightly the filter end plates fit within its can, and wonder if that is a non-filter-media related restriction point on the P1 in particular.


PureOnes don't seem to be very restrictive. Test data from Purolator:

http://www.bobistheoilguy.com/forums/ubb...451#Post1619451


It shouldn't be an issue- even though there's a very narrow gap, its an annulus and the cross-sectional area of a thin annulus is much larger than the human eye "thinks" it is just by looking. Still, its tighter than almost any other filter I've seen. M1's are pretty tight in that area, but not as tight as a P1.