High flow and premium brands.

[KCJeep]

Originally Posted By: edwardh1
wonder if japanese oem filters filter better than gm oem filters?


From the data I've seen, some OEM Japanese filters are just horrid in the efficiency department, such as Toyota, something around 50%, all the AC Delco tests I've seen were at least into the 90+ percent range. The Japanese OEM filters flowed very well though, so it may have been intentional, flow chosen over efficiency, but your generally going to get better flow with lower efficiency anyway, so whether it's intentional or not I don't know.

 

[WANG]

Originally Posted By: ccb056
Originally Posted By: coolbird101
This is interesting, GM did this study? From my understanding AC Delco is one of the least efficient filters available, why has GM not increased there filter efficiency?
Originally Posted By: ccb056
GM did a study where they found the following correlation between miles to first overhaul and filter micron ratings:

150k miles @ 45 micros 98.7% capture efficiency
200k miles @ 30 microns 98.7% capture efficiency
250k miles @ 20 microns 98.7% capture efficiency
400k miles @ 10 microns 98.7% capture efficiency

see: SAE Paper 881825


you can purchase the paper for $24 and read it yourself from here: http://papers.sae.org/881825/

Note the author: David R. Staley - General Motors Corp.

As to why ACDelcos have low inefficiencies, this is a business decision and not an engineering decision.


For the record, there is not a single mention of mileage in that paper. Not once.

 

[LeakySeals]

Originally Posted By: WANG
Originally Posted By: ccb056
Originally Posted By: coolbird101
This is interesting, GM did this study? From my understanding AC Delco is one of the least efficient filters available, why has GM not increased there filter efficiency?
Originally Posted By: ccb056
GM did a study where they found the following correlation between miles to first overhaul and filter micron ratings:

150k miles @ 45 micros 98.7% capture efficiency
200k miles @ 30 microns 98.7% capture efficiency
250k miles @ 20 microns 98.7% capture efficiency
400k miles @ 10 microns 98.7% capture efficiency

see: SAE Paper 881825


you can purchase the paper for $24 and read it yourself from here: http://papers.sae.org/881825/

Note the author: David R. Staley - General Motors Corp.

As to why ACDelcos have low inefficiencies, this is a business decision and not an engineering decision.


For the record, there is not a single mention of mileage in that paper. Not once.

Then where are the numbers coming from? Its the first time I've seen efficiency tied to engine life. I talk to people with 300+ on Toyota engines with no teardowns. They are using the low efficiency high flow Toyota OE filter.

 

[WANG]

The numbers previously quoted didn't come from that paper (881825). That guy either never read the paper himself, or read it and wanted to mislead people who have never read the paper. Not cool.

I will continue to use Motorcraft and AC Delco filters in the cages. No. Big. Deal.

 

[Jim Allen]

I also have that SAE paper and there is no such efficiency/mileage chart in it.
Shame on ccb056 for misrepresenting the study if he did it a'purpose. If it was a mistake, 'fess up for forgivess.

But since it was mentioned, IMO, that study is somewhat flawed in retrospect, at least as an example of filtration efficiency reducing wear. All it really tells you is how much wear is produced at specific levels of abrasive contamination... which is ultimately controlled by the oil filter... but it leaves a lot of the real world behind.

The thing is, those test contamination levels are way, way higher than most any engine will ever run, nor realistically be able to achieve in normal use. To build up that high a level of contamination, the engine would have to be in a very harsh, dirty environment, with a crankcase that is not properly sealed and an inefficient air filter. In other words, the only real world way you can achieve those level of contamination is with outside inpu, not from normal engine wear.

It's true that wear begets wear but abrasive contamination from normal engine wear particles generated (with clean oil) takes a very long time to build up to the levels they induced. I'm not even sure they COULD build up that high in the real world, given the great oils we have now and the fact that most engines are lightly used. They added 50 grams of fine test dust in an oil slurry EVERY HOUR FOR EIGHT HOURS to the diesel on the dyno and somewhat less to the gasser tested. That's 400 grams of material for the diesel and they had to change the filter several times to avoid bypass. When you think a GOOD, large capacity filter of today (and remember that test was done in '88) can hold 30-40 grams of material, and considering most oil filters aren't routinely loaded past 30-50% of capacity even in 10-15K miles of operation, we can see how unrealistic that test was. Except perhaps to the HD commercial markets with neglected/abused equipment that runs in very harsh environments.

The levels of contamination rise very slowly in the real world (the street environment with good air filtration and a sealed crankcase), so there are long periods of relatively clean oil, even without extraordinary filtration. When the rate of contamination is very slow, mostly coming only from the small, normal and mostly unavoidable amount of engine wear, plus the small amounts that gets thru the air filter, it takes a long while for the level of contamination to rise to the point of being a problem in terms of increased wear. In many cases, the oil is changed before that occurs. This is why Dave Newton can find no statistical evidence to support an assertion that improved filtration has any effect on wear in the real world of "normal" OCIs.

Better filtration maintains the level of contamination at a lower level but the issue of increased wear only becomes an issue once that level reaches one that significantly increases wear. Where that line will be exactly probably varies somewhat from engine to engine. The SAE test does give us hints at what that level is, but on a clean engine, at normal OCIs (even longish ones), essentially, that level is never reached.

As to flow, Zee said it right. The filter is far less restricting that the ports/galleries downstream of it and the only time the "restriction" of the filter is in play is when the system downstream of the filter is not pressurized. That's a momentary condition at startup, the duration of which is mostly controlled by the oil viscosity at the moment. Except in the high perfomrance realm, where the engine will do a lot of fast transitions from low to very high rpms, filter flow is not an issue.