Benefits of Running a Larger Oil Filter? (Cold starts etc)

[ZeeOSix]

I don't think he said that the oil filter is not important so take it out completely. He is saying that it won't matter if the oil filter is smaller or bigger, it doesn't matter if the oil filter is 99% at 20 microns or at 30 microns, use whatever oil filter you want and don't worry about it. But make sure you use a good air filter and make sure that it filters as it should because that will destroy an engine in short time.

In other words, use whatever oil filter and your engine won't know the difference.

My viewpoint is that it takes a better efficiency oil filter to achieve cleaner oil. Cleaner oil will always result in less wear with all other factors held constant, especially the longer the OCI, where a higher filter efficiency would benefit the most. Based on lots of studies, there certainly could be a wear level difference over the long run due to filtering efficiency - I'm talking a 99% @ 20u vs a 50% @ 20u or a 99% @40+ micron filter. It's not going to make a noticeable difference over an OCI or two ... it's over the long haul of the vehicle. Graph below shows the difference between 99% @ 20u, 30u and 40u filtration.

The bottom line is that the oil filter is the last thing to take care of any debris that enters the oil, regardless if that debris in generated internally inside the engine or is ingested from outside the engine, like from a bad or inefficient air filter. It's just funny that some people seem to believe that filtering oil better than not doesn't make any difference ... guess that's because their engine doesn't "blow-up" when using a low efficiency filter, which seems to be a common metric for if something works "good" or not in an engine.

 

[proveitwithdata]

i feel the warm fuzzies when i run a longer oil filter. I dont change anything else though.

 

[CR94]

Hi CR94,
I wonder if the filters have gotten smaller because the engines are cleaner burning combined with improvements in motor oils and fuel.
The filters I buy state a life in miles with an efficiency of 99% at 20 microns. As long as those are maintained I feel the product is sound. I'm not sure if those specs are considered the cheapest because OEM filters don't advertise any performance specs to compare to.

So you think the reason smaller filters were recommended for the car I referenced (the Mazda listed below) when it was old than when was new is that it became "cleaner burning" as it aged? I think the real reason was cost savings, plus perhaps a bit of inventory simplification.

 

[Bellavita]

So you think the reason smaller filters were recommended for the car I referenced (the Mazda listed below) when it was old than when was new is that it became "cleaner burning" as it aged? I think the real reason was cost savings, plus perhaps a bit of inventory simplification.

Great point CR94. Thank you.

 

[Bellavita]

So you think the reason smaller filters were recommended for the car I referenced (the Mazda listed below) when it was old than when was new is that it became "cleaner burning" as it aged? I think the real reason was cost savings, plus perhaps a bit of inventory simplification.

Hi CR94,
Another item that comes to mind is maybe the media evolves over time so less is needed thereby reducing the size of the filter. It does mean they're driving down cost but maintaining the filter performance they advertise. Or they pack more pleats and reduce the can size to again reduce manufacturing cost but maintaining the filter performance. Insights are always welcome!

 

[RDY4WAR]

I don't think he said that the oil filter is not important so take it out completely. He is saying that it won't matter if the oil filter is smaller or bigger, it doesn't matter if the oil filter is 99% at 20 microns or at 30 microns, use whatever oil filter you want and don't worry about it. But make sure you use a good air filter and make sure that it filters as it should because that will destroy an engine in short time.

In other words, use whatever oil filter and your engine won't know the difference.

I wouldn't say it won't know the difference. A more efficient oil filter will still be beneficial.

It's just the old saying "the best cure is prevention." The best way to keep the oil clean is to not let it get dirty to begin with. If you're using a junk air filter (*cough* K&N *cough*) that lets a bunch of dust particles through, that then get sucked into the crankcase by the PCV system, you're compromising the oil's cleanliness and those particles are too small for even the most efficient oil filter to capture.

A couple years ago, I was shown a comparison of particle counts of 2 UOAs from a 383ci SBC street engine. The 1st one had nearly double the particle count of the 2nd one. The 1st was with a K&N filter and 2nd one with a standard paper filter. The oil filter choice was the same for both oil changes and mileage was similar to within 10% along the same cruise routes and roads. Even up at 20-25 um, there was a substantial drop.

 

[henni]

i feel the warm fuzzies when i run a longer oil filter. I dont change anything else though.

This ½ applied. An oil filter in my jacket pocket during cold days.

 

[dnewton3]

Pros:
- Larger dirt holding capacity

Agreed. But unless the smaller one is maxed out (highly unlikely) then this is moot. Is it worthwhile to have a gallon of ice cream in front of you if you only want to eat a quart? Having "more" of something is only beneficial if the alternative is compromised or the extra capacity can be utilized. Generally, most engines are sufficed with the existing filter capacity, so having "more" capacity means zilch when it goes unused.

- Less likely to bypass

Not proven to be practically noteworthy. In theory, yet. But the inference taken is that they would affect wear rates. Hardly the case in reality; no data exists to prove your point, whereas plenty exists to prove it's moot.

- Increases engine oil capacity

Again, is "more" capacity good? Unless your current capacity is maxed out and harmful as a result, then "more" oil isn't doing anything. If "more" oil meant you'd run a longer OCI, then perhaps. Most folks will not alter their operation. And what, exactly, does this miniscule capacity increase represent? Perhaps a few more ounces in an engine that holds perhaps 192 oz; as if bumping from 192 oz to 195 oz is meaningful in terms of wear control or cooling capacity? That's a farce! Further, "more" capacity also means it would take that much longer to warm the oil to any desired temp. In cold areas, more capacity means longer warm-up times. Again, fractionally small at best, but the point is that for every ying there is a yang.

- Reduces the required pumping power of the oil pump, very slightly increasing fuel efficiency and engine power

I'm gonna disagree here; this would be improbable at best. And pretty much impossible to prove given all other variables in the equation.

- Can be cheaper if it allows for another OCI between filter changes

Again, are you proffering that a few extra ounces of capacity of oil, along with maybe a 10% gain in media, is somehow going to greatly extend someone's FCI or extend their OCIs? That's poppycock my dear sir.

Cons:
- Increases the time to build oil pressure on cold starts if filter doesn't stay full of oil between starts

If the filter is staying full (functioning ADBV), then this is moot.

- Can be more likely to get punctured by road debris, depending on filter location

True; a larger target is more easily hit.

- Potential engine warranty issues

Agreed. Both OE and filter makers clearly are given easy denial/delay opportunities should one venture off the reservation in filter selection. This comes down to the burden of proof as it relates to the Magnuson/Moss Act in regards to warranty provisions. When you use a recommended product, the burden of proof is at the feet of the product makers. When you do something not recommended, then the burden of proof is upon you, the consumer. They have massive legal teams and reams of study data, as well as time, on their side. What do we BITOGers have? Pontification and theory with no data to back it up.



Caveat Emptor, my fellow BITOGers.

 

[ZeeOSix]

I'm gonna disagree here; this would be improbable at best. And pretty much impossible to prove given all other variables in the equation.

If you use the hydraulic HP equation, and just look at the power reduction due only to say a 2~3 PSI reduction in dP across the oil filter with 8 GPM of flow at 80 PSI inlet pressure, the difference is super small ... like around 0.014 HP (~10 Watts ... an incandescent night light worth of power). It would be even smaller if just cruising around at low RPM and low pump oil flow volume. So yes, that would be masked by many other variables going on while driving around.

 

[ZeeOSix]

A couple years ago, I was shown a comparison of particle counts of 2 UOAs from a 383ci SBC street engine. The 1st one had nearly double the particle count of the 2nd one. The 1st was with a K&N filter and 2nd one with a standard paper filter. The oil filter choice was the same for both oil changes and mileage was similar to within 10% along the same cruise routes and roads. Even up at 20-25 um, there was a substantial drop.

What oil filter was it? If it wasn't very good efficiency below 20u then of course there would be higher particle count around 20u and below if the oil was contaminated more by an inefficient air filter. If the oil filter was 99+% @ 20u (putting it around 75-80% @ 5u) then it might have been a different result.

 

[twX]

If you use the hydraulic HP equation, and just look at the power reduction due only to say a 2~3 PSI reduction in dP across the oil filter with 8 GPM of flow at 80 PSI inlet pressure, the difference is super small ... like around 0.014 HP (~10 Watts ... an incandescent night light worth of power). It would be even smaller if just cruising around at low RPM and low pump oil flow volume. So yes, that would be masked by many other variables going on while driving around.

Yes, it isn't much of a difference. I did the math for my car, and a filter with half the restriction results in around a 0.05% to 0.5% improvement in fuel economy depending on conditions, maybe an average of 0.1% in cruising conditions with a warm engine. This is on a vehicle with a high flow oil pump.

 

[BigTimeTA]

a filter with half the restriction results in around a 0.05% to 0.5% improvement in fuel economy depending on conditions, maybe an average of 0.1% in cruising conditions

Still very well within the margin of error to attribute the savings to the filter.

 

[twX]

Generally, most engines are sufficed with the existing filter capacity, so having "more" capacity means zilch when it goes unused.

Of course, but it's difficult to know if and when a filter may clog. A dirty engine may clog a filter within a normal OCI. It's a matter of providing some additional headroom and reducing the risk of filter clogging.

- Less likely to bypass

Not proven to be practically noteworthy. In theory, yet. But the inference taken is that they would affect wear rates. Hardly the case in reality; no data exists to prove your point, whereas plenty exists to prove it's moot.

In normal wear conditions, occasional bypassing doesn't measurably increase wear. However, there is data to show that continuous bypassing can result in a modest increase in wear.

In worst case conditions, like during a component failure, an oil filter that bypasses large metal shavings can greatly increase engine damage. Race engines often have no filter bypass for this reason. It's not to reduce normal wear, it's to reduce the risk of a failed bearing or lifter trashing the entire engine. Most of the time it won't matter if a filter bypasses, but when it does matter, it can matter a lot.

 

[twX]

So you think the reason smaller filters were recommended for the car I referenced (the Mazda listed below) when it was old than when was new is that it became "cleaner burning" as it aged? I think the real reason was cost savings, plus perhaps a bit of inventory simplification.

I've noticed both FRAM and Purolator consolidating their lineup and eliminating filter models for my car. In both cases, they eliminated the larger filter. This is probably because it's too large for at least one of the recommended applications, so if they want to consolidate their lineup to save cost, they're usually going to be forced to eliminate larger filters.

 

[RDY4WAR]

What oil filter was it? If it wasn't very good efficiency below 20u then of course there would be higher particle count around 20u and below if the oil was contaminated more by an inefficient air filter. If the oil filter was 99+% @ 20u (putting it around 75-80% @ 5u) then it might have been a different result.

I'm not 100% certain, but I think it was Wix 51061.

 

[CR94]

I've noticed both FRAM and Purolator consolidating their lineup and eliminating filter models for my car. In both cases, they eliminated the larger filter. This is probably because it's too large for at least one of the recommended applications, so if they want to consolidate their lineup to save cost, they're usually going to be forced to eliminate larger filters.

That's the same trend I noticed. Eliminating the larger versions means decreasing efficiency, assuming the same media grade.

 

[Chris142]

When looking at the same brand filters, if the diameter is the same between two filters, but one is longer than the other, then the longer filter will have more media area.

Not always. Could have a different spring or valve in it that takes up more room.

 

[ZeeOSix]

Not always. Could have a different spring or valve in it that takes up more room.

Yeah, if one has a base end bypass vs a dome end bypass. But if same brand (as previously mentioned), and both have the leaf spring and bypass in the dome, then what I said will most likely be true , a longer filter with the same diameter will have more media (example, Fram 6607 vs 7317 or Fram 3614 vs 3600) . Never seen any filters in the same brand and model line use different leaf springs, or different coil springs if they use a coil spring.

 

[Rogueman2016s]

Nothing to be gained

 

[hrv]

Seems like after 3 pages the answer is NO....