oil filters

[brods]

Measuring the pressure on only one side of the filter won't tell you the oil flow rate. You must have the pressure differential across the filter. My bet is the 15 micron filter has a larger pressure drop than the 25 micron filter.



Put another way, I can easily build two systems which both have 65 psi at the filter exit, one of which has a flow rate of 0. 01 lbm/s and the other 200 lbm/s (the difference between the two being the flow velocity if we hold area fixed).



Ryan

You are on the right track, though it may be possible to get finer filtration with the same area with a similar pressure drop by using a more porous media, but of course there are limits and there will likely be tradeoffs, such as weaker media or shorter filter life, etc.



Getting back to differential pressure across the filter, when looking at oil pressure in the block one has to remember the oil system has a filter bypass of 50 psid built into the oil filter head. The stock oil filter does not have an internal bypass valve while, iirc, Wayne (Amsoilman) said the Amsoil filter (made by Donaldson) does. Iirc he said it was set for around 10 psid. So it would not be surprising that the Donaldson/Amsoil filter produces higher cold oil pressure at the block, though it may do so by allowing more oil to bypass the filter element than would happen with the Fleetguard filter. I have no idea if that has any significant impact on engine life, though personally I want as little unfiltered oil as possible going into the engine and turbo.



Anyhow, when only measuring the pressure in the block there is no way of knowing how much flow is going through the filter element and how much is bypassing it.

 

[rbattelle]

And I disagree with your statement on the systems. The systems would have to be of difference size/volume since pressure = flow x restriction. So if you have the same pressure and different flow you have to have different restrictions.

What units are you using for restriction? I've never seen that equation before, and I'm trying to understand from where it's derived. Looks like restriction needs something like [g/(s*ft)].

Anyway, it looks like we're in complete agreement. The 15 mic filter has a greater restriction than the 25 mic filter, owing to the fixed canister size. Which means the 15 mic filter is flowing less oil. This must be true, or else why stop at 15 micron? Why not 1 micron? Or are you suggesting there's no more restriction with the 15 mic than with the 25 mic?

If we can agree that decreasing particle size increases restriction, then how much restriction is too much? In other words, why did Cummins choose to stop at 25 micron? What are the flow margins on the Cummins B-Series?

Thats not to say the Fleetguard are crap, just not as efficient at filtering.

What definition of efficiency are you using?

Ryan

 

[brods]

Ryan, keep in mind that the oil pump is a positive displacement type and flow from the pump remains more or less directly proportional to engine rpms. The flow is not dependent on nor driven by the pressure. The pressure is the result of the resistance to that flow. The more resistance, the higher the pressure and the more energy it takes to turn the pump, but the flowrate does not change unless the engine rpms change.



All the flow will go through the filter until there is enough resistance to cause a bypass valve to open. Then some oil is going through the element while the rest is bypassing and the total flow to the engine is still the same. If the resistance gets so high that the 75 psi relief valve opens, then part of the pump's flow is dumped back to the sump and the net flow to the engine is reduced.



I guess what I'm trying to say is (in our engines) the filter's resistance does not effect flow across it until the resistance gets above whatever the bypass and relief valves setpoints are. I would assume this is primarily an issue during cold starts.

 

[rbattelle]

Brods, good points. I was thinking of it in terms of you have some device far upstream of the filter that is producing pressure. That pressure drives the flow. That's what I meant by "pressure driven flow".



The oil pump is a gearotor type, which isn't exactly a piston/cylinder positive displacement arrangement. Maybe I'm naive, but I expect with a gearotor pump the downstream pressure would have a non-negligible impact on the flow rate.



I recognize I could be completely wrong. But I keep going back to the fact that Cummins made the decision to go with 25 micron filtration (given the canister size), and they must've had a good reason to do so. Similarly, Donaldson had a good reason for stopping at 15 micron.



The real question is, what were these reasons? I am proposing that it was a flow rate issue, but again I recognize I could be completely wrong and something else drove these decisions.



I certainly recognize that filtering to 15 mic is better in terms of contaminant removal than 25 mic. But everything is a trade. That extra-fine filtration isn't free, and I think it would be a mistake to assume that any filter able to handle smaller particles is automatically "better" than one that won't capture similarly-sized particles. Know what I mean? We should think critically.



Ryan

 

[AH64ID]

What units are you using for restriction? I've never seen that equation before, and I'm trying to understand from where it's derived. Looks like restriction needs something like [g/(s*ft)].

I'm not using any unit, my equation is a general one. Pressure is a measure of flow time resistance. . no units needed. . just a very simple way to look at pressure. If you have a 3" hose moving "x" fluid then you will have "y" pressure. Take a 1" hose and move the same amount of fluid thru it then you have a higher pressure than "y".

Anyway, it looks like we're in complete agreement. The 15 mic filter has a greater restriction than the 25 mic filter, owing to the fixed canister size. Which means the 15 mic filter is flowing less oil. This must be true, or else why stop at 15 micron? Why not 1 micron? Or are you suggesting there's no more restriction with the 15 mic than with the 25 mic?

Were not in complete agreement. If you compare the same filtration media then yes we are in agreement, but Fleetguard and Amsoil/Donaldson use different filtration media's, so it is possible to have the same flow at 15um as 25um. In fact if you look at the OEM paper style filter you can probably get greater flow thru a tighter synthetic weave. This is why Amsoil/Donaldson filters have extended drain intervals, the media doesn't swell or vary from use. So as long as the filter isn't plugged it still flows the same. Direct from the stratapore website it states that the stratapore has lower flow restriction than its non stratapore counterpart. So right there it tells you that a good 25um filter can flow better than a cheaper 35um filter. So if the Amsoil/Donaldson media is better than stratapore there is no reason it can't flow the same or more. I would presume that 15um is the tighest you can go and not start to detract from flow.

If we can agree that decreasing particle size increases restriction, then how much restriction is too much? In other words, why did Cummins choose to stop at 25 micron? What are the flow margins on the Cummins B-Series?

Cummins most likely chose to stop at 25um because thats a pretty good rating for oil, and for most users its more than good enough. Amsoil/Donadlson went to 15um for that niche user that wants the best. Thats like asking why Dodge stopped at 325hp when programmers can get 400+ with all stock hardware.

What definition of efficiency are you using?

The absolute rating for a given filter, Amsoil/Donaldson are 15um absolute and Stratapore are 25um absolute (Both use ISO 4548-12). The Amsoil is more efficient at removing oil contaminates.

You are on the right track, though it may be possible to get finer filtration with the same area with a similar pressure drop by using a more porous media, but of course there are limits and there will likely be tradeoffs, such as weaker media or shorter filter life, etc.

It just depends on the media. The Amsoil/Donaldson has a finer rating as is a 25K mile filter, so the best of both worlds. If you look at this page link you can see why. The synthetic media itself is smaller, so you have more openings for flow than with a conventional filter, thus the finer filtering and increased flow and service life. (Stratapore is a synthetic media as well, but I can’t find any depictions on it. )

Getting back to differential pressure across the filter, when looking at oil pressure in the block one has to remember the oil system has a filter bypass of 50 psid built into the oil filter head. The stock oil filter does not have an internal bypass valve while, iirc, Wayne (Amsoilman) said the Amsoil filter (made by Donaldson) does. Iirc he said it was set for around 10 psid. So it would not be surprising that the Donaldson/Amsoil filter produces higher cold oil pressure at the block, though it may do so by allowing more oil to bypass the filter element than would happen with the Fleetguard filter. I have no idea if that has any significant impact on engine life, though personally I want as little unfiltered oil as possible going into the engine and turbo.

Amsoil/Donaldson does not use an internal bypass on the filter for our engines, the only bypass is the 50 psid that is part of the engine. So there is no unfiltered more oil going to the block than with any other filter. . and I would guess even less based on the uniform flow properties of the nano-fiber material.

Anyhow, when only measuring the pressure in the block there is no way of knowing how much flow is going through the filter element and how much is bypassing it.

I can verify that no filter is bypassing the filter with my gauge. I can do this because as you stated the psid required to bypass the filter is 50psi. The oil pump has a internal bypass that only allows ~75psi thru the pump. If I am cruising at 2K rpms I have ~60psi of oil, if there was a 50psid at the filter that would mean that the oil psi at the pump would be 110psi, which isn’t possible based on the 75psi dump at the pump. If the psid were met to bypass the filter I would expect to see no more than 25psi at cruise rpms.



Hope that’s all clear as mud 



I will reiterate that Stratapore filters are great filters, and if you’re just running normal drain intervals then they are the proper filter to run

 

[rbattelle]

Direct from the stratapore website it states that the stratapore has lower flow restriction than its non stratapore counterpart. So right there it tells you that a good 25um filter can flow better than a cheaper 35um filter. So if the Amsoil/Donaldson media is better than stratapore there is no reason it can't flow the same or more. I would presume that 15um is the tighest you can go and not start to detract from flow.

I think this is an excellent point, and perhaps the key to the entire argument. It all comes down to the media. Indeed, I was thinking that the media was more-or-less the same for both filters.

It also occurred to me that brods hit on something when he referred to the pump. We can have a higher filter restriction and keep the flow rate the same if we increase the power to the pump.

Ryan

 

[brods]

Amsoil/Donaldson does not use an internal bypass on the filter for our engines, the only bypass is the 50 psid that is part of the engine. So there is no unfiltered more oil going to the block than with any other filter. . and I would guess even less based on the uniform flow properties of the nano-fiber material.

Doing a little searching it would appear Amsoil just uses the Donaldson nano-fiber material and has an anti-siphon valve, while the Donaldson filter does not use an anti-siphon valve. It looks like neither have a internal bypass valve, which is good imo. Its not clear who actually builds the Amsoil filters and if they are indeed identical to the Donaldsons. Donaldson Endurance vs. Amsoil EaO - Bob Is The Oil Guy

I can verify that no filter is bypassing the filter with my gauge. I can do this because as you stated the psid required to bypass the filter is 50psi. The oil pump has a internal bypass that only allows ~75psi thru the pump. If I am cruising at 2K rpms I have ~60psi of oil, if there was a 50psid at the filter that would mean that the oil psi at the pump would be 110psi, which isn’t possible based on the 75psi dump at the pump. If the psid were met to bypass the filter I would expect to see no more than 25psi at cruise rpms.

Under the conditions you describe, I would agree with your conclusion. I would not expect any brand of filter to have enough restriction to cause bypassing when the oil is at operating temperature (unless it is extremely dirty of course). Under unusual conditions, like cold starts, then I disagree. Simply look at your cold oil pressure. It is higher than the 75 psi relief valve setting which would not be possible based on your reasoning.

... ... .

I certainly recognize that filtering to 15 mic is better in terms of contaminant removal than 25 mic. But everything is a trade. That extra-fine filtration isn't free, and I think it would be a mistake to assume that any filter able to handle smaller particles is automatically "better" than one that won't capture similarly-sized particles. Know what I mean? We should think critically.



Ryan

Couldn't agree more. The dilemma is we rarely know the reasons why one spec was chosen over another, so any deviation from stock is really a shot in the dark. Usually finer filtration is better, but as you wisely point out, everything is a tradeoff of some kind. It may simply be cost. And there is always the law of diminishing returns, so at what point are you spending more money for very little improvement. We'll never know for sure.



We also have to try to keep from getting too hung up on numbers. Real world performance is the bottom line and the advertised specs do not always give the whole picture. Again there is no clear answer unless someone with a fleet of trucks were to do side by side testing of the filters in the field and constantly run oil samples to see if one filter consistently out performed another.



Here is an earlier thread where oil filters were discussed and one operator saw no significant difference in oil samples. And yes one test is not a valid comparison, but its all we got. https://www.turbodieselregister.com...188775-stratapore-lf3894-vs-amsoil-eao80.html



Bottom line is our engines will last a good long time using stock filters and changing the oil regularly. Use whatever high quality filter makes you happy.

 

[AH64ID]

Doing a little searching it would appear Amsoil just uses the Donaldson nano-fiber material and has an anti-siphon valve, while the Donaldson filter does not use an anti-siphon valve. It looks like neither have a internal bypass valve, which is good imo. Its not clear who actually builds the Amsoil filters and if they are indeed identical to the Donaldsons. Donaldson Endurance vs. Amsoil EaO - Bob Is The Oil Guy

At least for our engine the filter is made by Donaldson, in fact its the exact same filter with a different wrapper. I have the Donaldson on my truck right now as it was $1 cheaper. I don't recall a drain-back valve on either of them. . its not really needed on a vertical filter.

 

[bheiting]

Here's my theory. I doubt there is a cost difference between a filter media that is
5 micron or 50 micron. So why wouldn't Cummins go with a 15 micron? Every
engine produces a certain amount of sludge. A 15 micron would certainly start
plugging up sooner than a 25 micron, not to mention cold weather oil flow.
A plugged filter equals a damaged engine.
Cummins is responsible for their engine warranty. Try getting Amsoil, Donaldson
or any other filter manufacturer to replace your engine. 15 micron looks a lot
better on a spec. sheet for those that don't know any better. I'll stick with
Fleetguard.

 

[HBarlow]

Here's my theory. I doubt there is a cost difference between a filter media that is
5 micron or 50 micron. So why wouldn't Cummins go with a 15 micron? Every
engine produces a certain amount of sludge. A 15 micron would certainly start
plugging up sooner than a 25 micron, not to mention cold weather oil flow.
A plugged filter equals a damaged engine.
Cummins is responsible for their engine warranty. Try getting Amsoil, Donaldson
or any other filter manufacturer to replace your engine. 15 micron looks a lot
better on a spec. sheet for those that don't know any better. I'll stick with
Fleetguard.

Makes sense to me.

 

[AH64ID]

Here's my theory. I doubt there is a cost difference between a filter media that is

5 micron or 50 micron. So why wouldn't Cummins go with a 15 micron? Every

engine produces a certain amount of sludge. A 15 micron would certainly start

plugging up sooner than a 25 micron, not to mention cold weather oil flow.

A plugged filter equals a damaged engine.

Cummins is responsible for their engine warranty. Try getting Amsoil, Donaldson

or any other filter manufacturer to replace your engine. 15 micron looks a lot

better on a spec. sheet for those that don't know any better. I'll stick with

Fleetguard.

I seriously doubt that you can get 5um filtration for the price of 50um... (Like 110% doubt) Thats the entire reason behind good quality synthetic media, better flow than a higher rated cellulose filter. You pay for what you get. A standard Mopar/Fleetguard filter is MUCH more likely to plug and cause flow restriction than a Amsoil filter.

 

[steved]

Alright, what's the problem with Purolator (in general, not for these engines specifically)?



I ask because I've been using Purolators on my Hondas for years.



Ryan

There is nothing wrong with them... I put 200k on my 99 using Purolators. I only run three filters: Wix, Purolator, or Fleetguard.



I look at it this way, any quality name brand will serve most of us fine for "our" relatively short oil change intervals.

 

[flyby night]

I use Napa filters, which are wix. Unless it is something that wix does not make yet, then they use Fleetguard filters labeled as Napa/wix. These are the only filters I will use if I have a choice. I believe they have the best quality overall.



As far as the micron rating of the filter, I use the finer micron rating option Napa# 7620XE with a micron rating of 14 with the synthetic media. I think this should be comparable to the stratopore version LF16035 from Fleetguard. I am just not as sure of the micron rating of the LF16035.



I do believe it is beneficial using the finer micron filter if you are going to use top quality oil and extend your drain intervals. If you are going to just use ok or good oil and maintain standard drain intervals, you are probably just fine using about any oil filter out there. If you are going to change your oil @ 3k miles heck, what do you even need a filter for anyways. So for 3k oci you are probably just fine with a fram, purolator, flag.....



From a fleet standpoint. I have seen better oil sample reports with the finer micron ratings of filters. I fell for the trap and tried the Napa XD filters for the S60's in the equipment that I work on. The XD's have a micron rating in the 35 micron range. The oil sample results showed a drastic difference in a negative direction on the equipment that these were installed on. The standard Napa gold rating for the S60 is 20 microns. I have found that I am better off using the finer rated filter and changing the filter only at 300-600 engine hours. The extended drains are rated at 35 microns so that they will not plug up during their extended use. What happens is that more of the nasty's are not captured in the filter media.

 

[SHobbs]

Anyone ever tried or looked at the Fleetguard LF 9028? Supposed to be a full flow and bypass all in one.

 

[pullya]

I just called Geno's and they assured me that the filter wrench(15 flute 93mm)they sell WILL fit the Fleetguard oil filters they sell. I also just checked the filters I received from Geno's about a month ago with the filter wrench I purchased from Geno's and the wrench fit all four of the filters.

Jay

 

[THolton]

just for kicks and giggles fram oil filter at wallmart $4 301k no problems change oil every 5k heavy hauler rotella 15-40 if ya count all three trucks 450k no problems -just me.

 

[blacksheepdiesel]

Who needs a filter flute wrench? One electrical connector and two clamps loosened and the intake air tube is removed for extremely easy access to the oil filter without laying on my back. I use the Fleetguard LF3894 and 12,000 mile intervals on Rotella 15W40.

Godspeed,
Trent

 

[THolton]

flute wrench- second time i changed oil in 03 cummins couldnt beileve how difficult the oil filter was to reach after carefull deliberation i took my die grinder with a cut wheel and removed just enough inner fender well to reach straight in over frame in front of tire and reach filter with my old style clamp filter wrench -works for me just fine nobody notices the little extra clearance and i will drive truck on farm untill its dead thats alot of oil changes with out fighting the oil filter

 

[steved]

just for kicks and giggles fram oil filter at wallmart $4 301k no problems change oil every 5k heavy hauler rotella 15-40 if ya count all three trucks 450k no problems -just me.

If you look at your Fram filters, they will most likely be XXXXA... the "A" is significant. It was the previous version *the non-"A"* filters that caused all the issues... during the switch from the 12-valve to the 24-valve (which has more pressure and heat).



The failures are not limited to Fram... there has been a recent increase in filter failures on BITOG, and they encompass a batch of different filters (not just Fram!).

 

[THolton]

thats right the fram ive always used has a a at the end of it- ph3976a been using this filter from 12v-24v-to common rail the only prob ive had with any oil filter on cummins is by hand tighten i have had some work loose over time three to be exact before i started using wrench to tighten wihen new. i think the gasket compresses by vibration from engine dont know for sure . a little snug pull with wrench putting it up towards crimp ring on filter and it has never been an issue since.