ok to use over-szied filter?

[Garak]

Originally Posted By: y_p_w
I doubt that material cost savings are that much of a concern given that pricing of filters at the retail level tends to be fairly uniform. I doubt that Purolator is charging the OEM more for a filter that's a half-inch longer but otherwise identically spec'ed.

Absolutely. The oversize for my G (and a few other applications I've seen) with Wix is actually cheaper. But, I would assume that's not the rule. Nonetheless, it does make sense for a manufacturer to be able to use, say, one filter only, rather than a small one for cramped quarters and a slightly longer one for a different model of car. Of course, we do see that, but one filter probably makes much more sense.

Look at the Infiniti lineup, and my G in specific. It calls for the small version. The oversize version, used in other Infiniti models, works just fine. There's enough room to weld two of them end to end. Yet, they use the small one for the G.

Even the oversized one is too small for a guy used to an FL1A.

 

[dnewton3]

Yes - if one is going to greatly extend the OCIs, then a larger filter makes sense. This, of course, is a nod towards warranty that has already expired, and so there is no risk in that regard. If you're willing to extend OCIs and monitor with UOAs, then choosing an alternate filter may make sense. However, the FILTER warranty is still in play; use an unauthorized filter and they can place the burden upon you. That is a long, uphill battle. It's already been discussed; no sense in beating that dead horse.

As for the cost savings of smaller filters from OEMs, I would agree. I've worked in manufacturing my entire adult life; if there is a penny to be pinched, most OEMs will try it. However, they generally will NOT do it if the savings is a warranty risk to them. So a smaller filter may save them a fraction of a penny, but when multiplied over hundreds of thousands of units, it adds up. I've seen it all the time. But ... that does not mean the smaller filter is unsafe or bad; it is still sized appropriately for the intended OCIs, and still has a safety factor built in. Of all the data I've ever seen, I've not gleaned any proof that filter size was the root cause of demise for an engine. Manufacting defects, improper installation, etc may cause equipment failure, but not a filter that appears too tiny to your critical eye.

The only reason you need a big filter is to catch a LOT of stuff, relative to the intended OCI. If you suspect gross contamination, then perhaps a larger filter is a prudent choice, But, if you have a well-made engine, that runs clean, the particulate loading is pretty darn small relative to the OCI. And often a 2x factor is safe for most filters. While your mind does not like to hear that, the data (admittedly scarce) shows this to be true. A few folks have actually done it and posted results here. Look at Jim's data regarding delta P bypass; look at 2010_FX4's UOA strings. Look at my Villager extended OCIs. Filters are not tasked nearly as heavily as folks tend to believe in a well-running engine, and therefore using a bigger one has no real tangible benefit. Until you would present a condition that would usurp the smaller filter, a larger one has no realized benefit. Unless you have a really sludged engine, or run a super-long OCI, the OEM filters are well more than up to the task.

If some of you disagree, that's fine. All I ask is that you put up PROOF, and not mythology and rhetoric. I've run long O/FCIs and posted data. Jim has run his experiments; so has 2010_FX4. If you want to contend otherwise, then bring factual data, and not supposition and marketing hype, please. In short, if you think a larger filter can actually be a TRUE, REALIZED benefit, then by gosh, show me your data from your testing. I don't want to hear your opinion; I want to see facts and data that substantiate your claims. Because from everything I see, filter size means zilch even up to 2x the OEM OCI, under "normal" conditions.

 

[Garak]

Originally Posted By: dnewton3
If you're willing to extend OCIs and monitor with UOAs, then choosing an alternate filter may make sense. However, the FILTER warranty is still in play; use an unauthorized filter and they can place the burden upon you. That is a long, uphill battle.

Yes, even check M1's 10000 mile or M1 EP's 15000 mile warranty fine print. The filter must be specified for the application.

 

[Olas]

This is no more than an uninformed assumption, but, in my head a larger filter should maintain oil cleanliness for longer, not only because there is more physical media to do the filtering and the velocity per cm2 of media is reduced, but I think there is another factor at play here..
Oil is polluted by blow by and condensation amongst other factors so if we take engine 'x' as an example - the engine pollutes its oil at a fixed rate per 1000 miles of use so if the overall oil capacity is increased, there is more matter to absorb that pollution before the TBN is depleted and/or the particulates and insolubles reach a critical level. I could be wrong but I think this is one of the main, and most commonloy overlooked, benefits of oversized filters.

My app. specs a Mahle oc47 but I use an oc51 or oc105 for the increased volume while the other specs remain the same.

HTH

 

[Garak]

How much extra volume do you get, though? Some filters have some very large oversized options. The basic oversize for my G probably gets me less than 100 mL of extra oil.

 

[Olas]

The oc51 is around 500ml extra, the oc105 is another 400ml on top of that, or approx. 1 litre on top of the oc47.

I just had another thought, could the increased capacity lead to a reduction in oil temp? (note, I did not say "significant" lol)

 

[Garak]

Well, 500 + mL of oil is definitely a little better than 100 mL or less. At least in such a case it might be advisable to pay extra attention when filling after an oil change. When I happened to use an oversized filter in the G, it was absolutely unnoticeable on the dipstick.

I suppose it could lead to reduced oil temperatures, and that's often a touted benefit, but like you said - you didn't say significant.

If my G went from a dixie cup sized filter hiding out of the air flow to something bigger than an FL1A dangling in the air, particularly on a cold day like today, maybe.

 

[Jim Allen]

IMO, the main benefit to oversized filters is a probably the reduction of bypass events in the most common situations where they occur due to a decrease in differential pressure (more media=more pores for the oil to flow thru... more "flow" if you want to think of it that way). Those common periods are cold starts and WOT operation ( especially with oil that isn't fully warmed up). The secondary benefit is the ability to run longer FCI because you have increased the contaminant capacity. In everyday operation with the correct viscosity of oil and correct filter for the application, the differences in flow are inconsequential and of negligible importance.

 

[KCJeep]

The oversize for my Jeep (FL-1A equivalent) will net me exactly 8 oz extra capacity. Not significant IMO however it does make the capacity jump to exactly 6 quarts which is handy. I run both, or often a slighty undersize FL-400s and have not yet been able to discern any difference in operation, performance or results.

 

[ZeeOSix]

Originally Posted By: Garak
How much extra volume do you get, though? Some filters have some very large oversized options. The basic oversize for my G probably gets me less than 100 mL of extra oil.


The most accurate way to know would be to fill up each new filter and measure how much oil it took to fill each one completely.

An "average sized" oil filter holds about 8 oz of oil from what I've measured.

 

[ZeeOSix]

Originally Posted By: Jim Allen
IMO, the main benefit to oversized filters is a probably the reduction of bypass events in the most common situations where they occur due to a decrease in differential pressure (more media=more pores for the oil to flow thru... more "flow" if you want to think of it that way).


+1 ... it would be interesting if you could do a delta-p test on a specified filter for your truck, and then one that is "over-sized" on your truck while using your delta-p data recording equipment.

 

[Jim Allen]

Originally Posted By: ZeeOSix
Originally Posted By: Jim Allen
IMO, the main benefit to oversized filters is a probably the reduction of bypass events in the most common situations where they occur due to a decrease in differential pressure (more media=more pores for the oil to flow thru... more "flow" if you want to think of it that way).


+1 ... it would be interesting if you could do a delta-p test on a specified filter for your truck, and then one that is "over-sized" on your truck while using your delta-p data recording equipment.


It's on the list but I have some fitment issues to check on. The filter base I added reduces the space available for a longer filter. Also, I have to find two filters with the exact same media, one with more than the other, to make a fair comparison.

 

[martinq]

Originally Posted By: Jim Allen
IMO, the main benefit to oversized filters is a probably the reduction of bypass events in the most common situations where they occur due to a decrease in differential pressure (more media=more pores for the oil to flow thru... more "flow" if you want to think of it that way). Those common periods are cold starts and WOT operation ( especially with oil that isn't fully warmed up).

The secondary benefit is the ability to run longer FCI because you have increased the contaminant capacity.

I'll add that by increasing the filter area you reduce resistance (assuming same media/construction) and increase flow. The benefit is also increased filtration efficiency from the lower velocity through the media.

 

[ZeeOSix]

Originally Posted By: martinq
Originally Posted By: Jim Allen
IMO, the main benefit to oversized filters is a probably the reduction of bypass events in the most common situations where they occur due to a decrease in differential pressure (more media=more pores for the oil to flow thru... more "flow" if you want to think of it that way). Those common periods are cold starts and WOT operation ( especially with oil that isn't fully warmed up).

The secondary benefit is the ability to run longer FCI because you have increased the contaminant capacity.

I'll add that by increasing the filter area you reduce resistance (assuming same media/construction) and increase flow. The benefit is also increased filtration efficiency from the lower velocity through the media.


A less restrictive oil filter can only "increase flow" when the oil pump is in pressure relief. Otherwise, when a positive displacement oil pump is below the pressure relief point, it forces all the volume through the filter & engine oiling circuit - that's why it's called a "positive displacement" oil pump.

A less restrictive oil filter does however give slightly more "headroom" so the oil pump operates a little farther away from the pressure relief point.

 

[Garak]

Originally Posted By: ZeeOSix
An "average sized" oil filter holds about 8 oz of oil from what I've measured.

There you go. With respect to my G, I likely overestimated how much extra volume there would be, even with a relatively low amount of like 100 mL.

 

[dnewton3]

Originally Posted By: ZeeOSix
Originally Posted By: martinq
Originally Posted By: Jim Allen
IMO, the main benefit to oversized filters is a probably the reduction of bypass events in the most common situations where they occur due to a decrease in differential pressure (more media=more pores for the oil to flow thru... more "flow" if you want to think of it that way). Those common periods are cold starts and WOT operation ( especially with oil that isn't fully warmed up).

The secondary benefit is the ability to run longer FCI because you have increased the contaminant capacity.

I'll add that by increasing the filter area you reduce resistance (assuming same media/construction) and increase flow. The benefit is also increased filtration efficiency from the lower velocity through the media.


A less restrictive oil filter can only "increase flow" when the oil pump is in pressure relief. Otherwise, when a positive displacement oil pump is below the pressure relief point, it forces all the volume through the filter & engine oiling circuit - that's why it's called a "positive displacement" oil pump.

A less restrictive oil filter does however give slightly more "headroom" so the oil pump operates a little farther away from the pressure relief point.



You know, so many folks make the wrong presumption about why the filter bypass exists in the first place.

Generally, the bypass valve is not there to protect the engine; there is way more flow (volume and velocity of oil) supplied by the pump than the engine needs. Any excess "flow" is burped off at the pump relief. The high pressure at the cold start cycle cannot be interpreted to mean that the engine is starving for oil. It is only an indication that pressure in the system is building due to OVERALL SYSTEM resistance, not just at the filter. Jim's data shows that the filter bypass will open under very limited circumstances, but when it does, that should NOT be interpreted to mean that the engine was starving for oil. It ONLY means the media was being protected. Once relief starts (within fractions of a second) the output from the filter is balanced again to system pressure. The bypass valve in the filter is to protect the media from being blown out (for a lack of a better term; not outwards, but torn, etc). The pump relief operates on a principle of delta P between oil circuits and atmospheric pressure (typical vented sump system). But the filter operates on dP across the media. Don't confuse the two, or their intended functions.

I will also note that the size of the opening for the bypass valve in the filter is likely large enough to pass enough volume and velocity that the engine would not starve for oil in the critical pathways, should the media ever blind off to a point of total obstruction (think total neglect). The only time the media is at risk is when the delta P across the media is high enough, long enough, for the media to succumb to destruction. That is practically never, folks. In short, even fully blocked media should not keep oil from reaching the engine. It would be undesirable because it's unfiltered, but the engine surely would not starve for oil.

The only time the engine is at pressure and flow risk is when the pump isn't performing to a minimum requirement, or the relief valve is stuck open.

As for filter bypass events, I've said this before and I'll say it again. Results trump theory every time.
One of two conditions MUST exist; there are no other alternatives.
1) filter bypass events are frequent
2) filter bypass events are infrequent
Either way, where is the data to show that one theory results in heavy wear trending versus the alternative? We have some decent data from Jim to show that the truth is predominant in condition 2. But does it really matter overall? Will a larger filter (all other conditions being equal) result in any tangible difference in wear? Wear being defined as statistically significant that can be counted upon as proof in a UOA, or in teardown analysis ... I see none. Feel free to point it out if you have access to it, because it would be of profound interest to me. To be truly viable data, we'd need a large series of sample UOAs in both conditions. Read my article on UOA normalcy to understand the basics.

The ONLY time I could see a larger fitler being of use is if the following operational conditions happened:
1) the "normal" filter was used so long that it totally blinded off the media, and the filter was in perpetual bypass (a larger filter would not prevent this, but it could defer it in time)
2) the continual contamination accumulation was great enough that the oil add pack was eventually overwhelmed and could not contain the harmful particulate in a manner to prevent wear escalation; in essence the particulate load would overcome the additives and attack the barrier in a manner sufficient to alter wear trending

Let us not forget SAE 2007-01-4133 that shows longer O/FCIs indicate that wear trends DOWN as the OCI gets longer (at least out to 15k miles). There most certainly is a point where wear would reverse its trend, and start up. But we have no DATA, no FACTS, to show when that would be. AND, that study did not utilize different filter sizes; that would be an entirely different study all together. The main contolling entity in wear control is NOT the filter; it is the tribochemical barrier that is developed after OCI. Would it be your supposition that a larger filter would have made for even less wear in this study? The wear was down by a factor of 10 after just a few thousand miles for goodness sake! The wear was so negligible that it was almost non-existent! Just how much "better" do any of you think a "bigger" filter would make it????? The only way to know how these would react independently would be to run several DOE tasks where you manipulated the OCI and FCI, only AFTER the wear trends were affected. You would have to run control groups and study groups. You'd have to seek to affect the wear by manipulating the filter media only AFTER the wear trended up in "normal" circumstances. How many of you have tried this? How many of you have read about this? To this date, I have NEVER seen any such study.

My closing points are these:
- there is reasonble data to show that bypass events are infrequent (Jim's data and his affirmation of information from engineers in the filter industry)
- there is reasonable data to show that bypass infrequent events are harmless (thousands of UOAs here and elsewhere)
- there is reason to conclude that filters do not directly affect lube flow to a point of equipment starvation with components in good condition (pinciple understanding of hydraulic systems)
- there is reasonable data to show that OEM filters (even at 15k miles) offer fine procection, complimentary to the tribochemical barrier (SAE study)
- there is no data to show that larger filters would alter these conditions, at least in a practical sense where any BITOGGer would ever tread


To coin a phrase ...
The only thing a Bittoger has to fear is filter fear itself.

 

[KCJeep]

Good post Dave!

 

[ZeeOSix]

Originally Posted By: dnewton3

Generally, the bypass valve is not there to protect the engine; there is way more flow (volume and velocity of oil) supplied by the pump than the engine needs. Any excess "flow" is burped off at the pump relief.

The bypass valve in the filter is to protect the media from being blown out (for a lack of a better term). It does nothing to save the engine from destruction.


The filter bypass actually does both at the same time. If the filter couldn't bypass, then the filter media would be damaged, and the flow of oil to the engine would be significantly cut off ... so it's purpose is to simultaneously prevent both of those bad things from happening.

Originally Posted By: dnewton3

The pump relief operates on a principle of delta P between oil circuits and atmospheric pressure (typical vented sump system). But the filter operates on dP across the media. Don't confuse the two, or their intended functions.


True ... two different systems with two different, non-dependent functionality.

Originally Posted By: dnewton3

I will also note that the size of the opening for the bypass valve in the filter is likely large enough to pass enough volume and velocity that the engine would not starve for oil in the critical pathways, should the media ever blind off to a point of total obstruction (think total neglect).


I'm not so sure the engineers in all cases have designed the bypass valve to take 100% of the flow from the pump based on the size of some of the bypass valves I've seen. If the filter media became totally blocked off, and all the oil volume was forced to flow through the bypass valve, the filter would be operating at a much higher delta-p (as compared to normal unobstructed flow through the media), which would cause the oil pump to hit pressure relief much sooner while at a lower output volume. This would then decrease the total oil flow volume going to the engine. In most cases (ie, low engine load, low RPM and low oil flow volume), the engine could probably survive with all the oil flow going through the bypass valve. But if the filter went in to total bypass when the engine was at high load and RPM where it needs high oil flow volume, then it may not survive as well. This is a rare case however.

 

[dnewton3]

Regarding your last point, I agree overall, but I'll point out this ...

The pump relief is typically a linear progression spring device not unlike the valve in the filter. I've not known any pump relief to be an "on/off" switch with a high/low setting. They will bleed off pressure as it builds, in a variable response to the overage. Like the filter bypass valve, it will first crack open, then bleed more as the pressure increases. It's not like the pump relief opens and then 100% of the pressure is bled to the sump, while the engine gets zero. Rather, it only bleeds off the excess pressure , keeping the engine satisfied.

So, in my example above, when the filter media is totally blocked at it's bypass open, the pump will supply enough pressure and volume regardless, even if it is in relief to some degree.

I would agree that there is some portion of unknown risk whereas the filter bypass hole may not be large enough for a total-meltdown stupidly ignored condition (filter NEVER changed, totally blinded media, and full revs at cold start with 15w-40 in a gasser in Alaska in winter ....). But then again, how many BITOGers get into that condition anyway? In fact, I believe that general neglect of equipment is actually rare, and only gets massive attention because of its notoriety. It's certainly not the norm. And it's practically a non-event in the BITOG world, where oil and fitlers are changed WAY more often than necessary.

So to the point in this thread (and too many others) about "needing" a larger filter for a standard application, where the reasonable expectation of actual filter lifecycle is never even threatened at all, the perceived benefit of that larger filter never presents any actual data that it's "better" in real life, because the regular option is never compromised to a point of risk/failure where it would truly effect the engine with chronic (wear) or acccute (starvation) issues.

I fully agree that generally equivilant larger filters are not an operational risk, but they most certainly are a warranty risk (both OEM warranty and filter-maker warranty) because those entities will make every attempt to void the warranty for non-approved applications, and since most folks misunderstand the whole M/M Act issue, the reality is that the burden of proof would lay at one's own feet, and that is a VERY heavy burden to haul.

 

[Bgallagher]

Been using PF52 in place of my PF47 for years now. No difference in flow rate etc. just longer. Probably all in my head but I feel like it runs a little quieter with the longer filter versus the shorter.