That is exactly correct. It is the reason for the "R" suffix for UPF48R. I still have a hard time believing that the UPF48R being a Gold Premium filter has the same filtering media as the PF48. The whole purpose of the Delco Gold line of filters is to provide premium features with finer filtration than the standard filters.

 

I like the K&N filter. You can remove it with wrench, which is a great help if you do your own oil change.

 

I am the technical manager at FRAM. The "independent studies" you quote do not have any actual filter tests in them. Just a dude cutting open filters and offering his opinion, wether it makes sense or not. They always only look at the least expensive fram filter and rate it poor because it has fiber end caps on the media cartridge. Guess what else does? AC Delco. In fact, it doesnt have fiber end caps, it has felt end caps and a plastic center tube. Does that mean it is not a good filter-NO, it is a good filter. Why, because the end cap serves one purpose, to seal the media cartridge, nothing more.
If you want to see photos, please by all means send me a email at jay.buckley@honeywell.com. I cannot post pictures on this forum but would be happy to send you photos of what is inside a AC Delco filter. We make a filter called extended guard. This filter is a two ply full synthetic media wrapped around a stainless steel screen. It has silicone antidrainback valves and capacity for 10k oil changes. I have used on my LS6 CTS-V since new, change oil (mobil 1) when the change light comes on (around 9300 miles) since new. The car is driven very hard and does monthly track and drag strip days. My compression and leakdown are better at 53k miles than they where new. The inside of the engine is spotless. What any of you should be concerned with when shopping for oil filters is test results from ISO 4548-12 filter testing. This is the only valid oil filter test recognized by automakers around the world. We (unlike most of our competitors) publish the efficiency ratings from this test. Most aftermarket filter makers do not. If they do publish results at all, the use the old SAE tests obsoleted in 2002. WHY? Those are easy to skew because they do not state particle size. Any filter can be 99% efficient at removing bowling ***** from your oil.
BTW- Mobil !, K+N, Amsoil are not filter manufacturers, they buy filters and slap thier names on them. Cut open a mobil1 and a K+N, notice some similarities? At least they have different paint jobs and K+N has the nut. OK, done ranting. and planning to buy a Z06 the minute the last payment goes on the V.

 

Can you post a link to ISO 4548-12 test results?

Oil filters are often debated here.

 

i use a wix's filter

 

Thank you so much for posting this. Frams have been bashed on all the car forums because of the idiot cutting them apart and judging how they are made. Thanks.