[Zonaman]

I wanted to see for myself what the difference was between K&N Air filter vs Paper (NAPA). So here's what I did. I ran each filter about 5500 miles then sampled the oil (Mobil 1 10w30) and sent it to a lab for analysis. Here's the particle count results:

K&N
SIZE NUMBER/ML
4 um 37960
6 um 1449
14 um 139
21 um 33
38 um 20
70 um 13

ISO 11171 CODE: 22/18/14

Paper:
SIZE NUMBER/ML
4 um 419920
6 um 4860
14 um 113
21 um 75
38 um 45
70 um 30

ISO 11171 CODE: 23/19/14

If I'm reading this right, the paper filter (which actually had a few hundred less miles on it) was dirtier! Same truck, same driving conditions. Only difference: I was using a Delco oil filter on the K&N and a NAPA Gold oil filter with the paper.

I was really suprised! I expected the opposite results. So it looks like the K&N is superior- at least on my truck. What say you?