from the test you noted...Bob the oil guy
"The test subject was the K&N air filter. Yes it let many particles pass through"......my experience too.
I need every last ounce of filtration where I live. Dirt road for 1/3 mile to my home...the dust is fine and with the lack of humidity hangs in the air when a vehicle passes or your tires kick up the soil.
With a K&N I had dust/particulate matter thu the element enough to clog my carb jets. When I changed to paper filtration the inside of the housing and carb body was clean.....not scientific certainly but I could figure that out.
Paper seems to work very well on that type of particulate matter it appears.....his test was in western Wash, hardball roads, high humidity so was not dealing with the same issue.
He did say paper filtered better but not as good as he thought it would.....maybe he should test under different conditions. That was a pretty limited study.
Anyways, go with what works for you....my field study indicated my choice.
Last edited by Reiver; 12-18-2017 at 06:22 AM.