[NOS2Go4Me]

I see what's going on here... they tested with a diesel, which really does need a good quantity of air to begin with. Secondly, they didn't do any after-test wear checks against the internals of the engines, nor did they extrapolate they overall additional cost of using an aftermarket filter either. They simply grabbed a drum, started banging, and began chanting "K+N Bad!".

Let's be serious for a second. Do you really think K+N makes filters that are harmful to your engine? These things are used in just about every vocation and application available to an internal combustion engine. Furthermore, they have a very effective filtering system that doesn't die off anywehre near as fast as paper filters do as it begins to accumulate dirt. Also, how much dirt really makes it into your engine bay and airbox? See the above comment about pro-rated wear and tear over time not being evaluated... because it's pointless. I'd speculate that more dirt gets into the engine via the fuel system and filter being clogged than via the intake... or it's pretty darn close. Either way, a proper investigative test that actually examines the engine prior to and after the tests is needed before claiming what those guys are saying to be true.

Also, for this one test that says you don't make horsepower with an aftermarket filter (and I beg to differ on that personally), how about all the dyno tests by both K+N themselves and aftermarket retailers / speed shop owners that show the increase in air significantly improves performance, fuel economy, and throttle response? I'm completely not convinced that one test should discourage anyone from using an aftermarket filter at all.

Just my opinion.

EDIT - http://knfilters.com/facts.htm - they use a certified test base as well, and are certified by the SAE. No too shabby for the credentials. They speak to what levels they specifically counter particulate, and why they work the way they do. Not much more to be said there.