Enginemasters new episode 4/30 oil filter showdown!

[Davejam]

Engine wear is also dependent on what I call the product of oil cleanliness times miles ran. A more efficient oil filter helps keep oil cleaner the longer the oil is ran. If the oil was dumped from the sump every 500 miles you wouldn't even need much of a filter, if any.

Based on the studies, the 4u and 14u particles would probably have the most potential for wear. And as most know, if a very efficient filter is used, the number of all sized particles decrease - that's an advantage of a high efficiency oil filter that some may not realize. If a filter is 99+% @ 20u, it can also be 75-80% @ 5u.

The bottom line is that trying to keep oil as clean as possible doesn't hurt anything and is helping reduce some engine wear. And it's a misconception to believe that particles less than 20u aren't doing anything. They do as shown in studies, and that's why big rigs, etc use bypass filtering in order to remove more particles less than 20u when they run oil for a super long OCI.

I don't disagree that cleaner oil is beneficial overall. And yes there is a time/mileage aspect to the overall picture.

What i'm saying is that a single 4 micron particle will contribute less wear than a 14 micron particle. And a 14 micron particle contributes less wear than a 21 micron particle.
Ignoring the fact that a coarser particle is more likely to be caught by a filter.
We disagree here. There is competing information that we have both cited.

In diesel engines it seems filtration to lower particle size is desired. I don't quite understand why that is.

 

[OVERKILL]

I don't disagree with this but it is a measurable amount of BHP at the high limits of flow.

But they measured HP with and without the oil filter installed and concluded it made absolutely zero difference.

And apart from small gains in HP we see the added advantage that a higher flowing media will not see bypass until much later.

Assuming we are talking about the media bypass, that's exactly right. A higher flowing media will have a lower delta-p for a given feed volume, meaning that it would require more volume to create a sufficient differential to engage the bypass.

This is unfortunately impossible to discern (whether the media bypass was kicking in or not) with this test because of the pump being on the relief, so volume was allowed to change, distorting the picture.

Had they used a lower volume pump with a known higher relief pressure and provided the actual curves it would be easy to see when the relief came into play and also an idea as to what the pressure drop across the media was even if not measured. Of course ideally, they'd measure at both locations, providing us with delta-p directly rather than forcing us to infer it from the data.

Hopefully, they will revisit the episode to discuss whether the engine was in relief etc. Also, it seems forever that anyone will correctly test for the filter bypass. Cheers.

Yes, the last time I saw some filter bypass testing it was done on here by member Gary Allen, who unfortunately passed some time back. He ran a set of gauges with one measuring before the filter, one measuring after. I'm sure one could find the thread if they looked hard enough, but the conclusion was that most of the time, the filter was not in bypass and the differential pressure was minimal for most operating conditions with the engine up to temperature.

 

[ZeeOSix]

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What I've explained, and Zee has explained is that when the pump is not on the relief, the oil filter is "transparent" in the flow through the system; it has no impact in how much oil enters the rest of the engine.

All of the other factors you mentioned aren't relevant to what we are discussing, since the filter is the FIRST thing after the pump, the oil has nowhere to go but through the filter, think about it. If the pump is not on the relief and it displaces 1 gallon of oil, where does that gallon of oil go? It MUST go through the filter.

I think I've tried to explain that simple concept a few different ways. Oil volume that leaves the pump can not magically change to a different volume. Even if the pump is in pressure relief, all oil volume leaving the pump and not diverted to the sump or pump inlet still leaves the pump. "Leaving the pump" means it's being sent into the oiling system towards the oil filter.

Post #89 is about as simple an explaination as possible. If 5 GPM leaves the oil pump, then 5 GPM goes through the filter and then through the oiling system. If anyone can't understand that concept, then they wont be able to understand how a PD oiling system operates.

 

[ZeeOSix]

Lol everyone is a troll here. You started at zero restriction even though there is a bypass in the filter.

Who said "zero restriction"? The bypass valve in the oil filter has no affect on the flow restriction of the filter until it opens, which it shouldn't do (open) with oil at full operating temperature. We are not talking about NASCARs here with 30 GPM oil pumps, so forget that tangent.

Less flow, more HP to maintain but you wouldn't see it on any fram ultra because at high revs and HP it will be constantly in bypass. So do you want high flow then.

On a nornal high performance street car, an Ultra or any other filter that flows similarly isn't going to put the filter in bypass if the filter isn't clogged up with debris and the oil is fully hot.

The "get more HP with a better flowing filter" is all hype because its been shown many times now that the BHP difference because of a few PSI of delts-p across a filter is so small that it can't even be measured on a dyno and makes no difference in the real world of street car engines.

 

[ZeeOSix]

If the delta p is different the flow through to the filters clean side is different.

That's not how it works, and seems why you're having problems seeing what's really happening. If 5 GPM coming from the pump goes into the oil filter, then 5 GPM must also come out of the filter. If the flow going through the filter somehow makes it change, how exactly does it magically change the flow volume by going into the filter then back out the filter? If you can't grasp that you're going to have some major problems understanding an oiling system.

The delta p itself proves the filter is a restriction.

Of course ... nobody here has ever claimed that an oil filter has zero flow restriction. The delta-p across the filter is because there is some slight flow resistance from the filter from the inlet holes, media, and center tube holes. But as the flow vs delta-p curves have shown, the delta-p is just a small fraction, like around only 6~8% of the total flow restriction of the engine itself.

 

[OVERKILL]

Even if the pump is in pressure relief, all oil volume leaving the pump and not diverted to the sump or pump inlet still leaves the pump. "Leaving the pump" means it's being sent into the oiling system towards the oil filter.

Definitely, my point of highlighting the significance of the pump not being on the relief is because the filter ceases to be transparent if its resistance is what has put the pump on the relief and reduced volume. At 5gpm if the system resistance is 60psi and the filter adds 5psi of resistance and the pump relief is 65psi, the filter is then what ends up putting the pump on the relief and subsequently flow increase with RPM stops being a direct relationship. Of course every drop of oil that leaves the pump still has to go through the filter, but by the relief coming into play, some of the volume the pump is moving is shunted back to the feed side and never leaves the pump. The system becomes more dynamic once the relief is activated.

 

[ZeeOSix]

I don't disagree that cleaner oil is beneficial overall. And yes there is a time/mileage aspect to the overall picture.

What i'm saying is that a single 4 micron particle will contribute less wear than a 14 micron particle. And a 14 micron particle contributes less wear than a 21 micron particle.
Ignoring the fact that a coarser particle is more likely to be caught by a filter.
We disagree here. There is competing information that we have both cited.

If you believe the data from Cummings and Pall, particles 10u or less contributed to the most engine wear overall. Yes, less of those particles 10u or less are caught by the oil filter, depending of course on the efficiency of the filter. As I mentioned before, a filter that is rated at say 99% @ 20u is going to also catch more particles that are less than 20u compared to a less efficient oil filter. A filter rated at 99% @ 20u may also be capturing 75-80% of all particles 5u or larger.

I don't really see any "cometing information". All the studies I've read all conclude that keeping the oil cleaner results in less engine wear. Nobody can find any study that shows that dirtier oil results in less wear or even the same amount of wear.

In diesel engines it seems filtration to lower particle size is desired. I don't quite understand why that is.

Because most diesel engines run very long OCIs, so it comes back to the "time/mileage aspect". Engine wear is a function of "oil contamination level times the length of time the oil was used". Think of it as an abrasive slurry of contaminated liquid pushed through the oiling system X number of times. The dirtier it is, and the more times it's pushed through the system, then the more engine wear there is.

 

[ZeeOSix]

With no filter, the pressure was 79psi at peak:

This data summary shows that that there is a lot of "noise" in the data acquisition, and/or the oil temperature was not exactly the same on each run. As OVERKILL has pointed out, the oil temperature is an important parameter to control in a test like this.

Look at the flow rate vs oil pressure information. It's a fact that an oil pressure sensor located after the filter is also an indirect measure of the oil flow volume. If the same oil was exactly at the same temperature, then the oil pressure at the sensor would read exactly the same if the oil flow through the system was exactly the same. There should be a direct correlation in that case (ie, the higher the pressure, the higher the flow), but there isn't in these test cases.

For example, the data shows 7.2 GPM with a pressure of 77.6 PSI, and 7.6 GPM with a pressure of 74.9 PSI. That is totally opposite of how it should react if the same oil is at the same temperature. So more inconsistencies going on here.