What would be the iso test efficiencys!?. I read,carquest.com, the blue-premium air filters,are 99% @20 microns.how about a.c. DElcos,and napa golds effeciencies!?
Thats a great test, have seen that before. I used to use k&n yeeears ago, but stopped after seeing alot of "dust" in intake piping. Years later I have seen quite a few ruined diesel engines, and many performance issues. Just had a couple year old Ram(6.7 cummins) last week, in for a MIL on, and low power. Low boost and intake restriction codes. Pulled out the somewhat dirty looking k&n and popped in a new OEM, and it was fixed. Customer wasn't happy as he had to pay.If you want true efficiency comparisons, you need to contact or find the manufacturer's ISO 5011 efficiency info, and pay attention to what test dust (fine or course) was used in the test.
Example of the real way to compare air filters.