[Christ]

Originally Posted by jamesqf

Just for a guess, maybe because with the K&N it's not the size of the holes, but that the dust particles get trapped in the sticky oil? At least that was what happened with the "wet" filters I used to deal with on logging & construction equipment, where oil would circulate and the dust would settle out in the bottom pan... (Sorry if my description isn't clear: it's been a couple of decades.)

I know exactly what you're talking about here, but I haven't seen an implementation of it in years.

The K&N surely is designed to catch particulate in the oil, and the oil expands the cotton gauze to close up the holes some. The problem is that when the size of the holes are measured, it's (ideally) done after the filter is "ready for service". So that would mean that even after the oil is placed on, and all tests are performed, the K&N filter still flows larger particles than the normal pleated paper filter does.