synth19

My friend with an M3 fwded me some articles from his BMW list... What do you guys think?

foam filters versus K&N filters:
www.seansa4page.com/resource/airfilter.html www.ibmwr.org/otech/airfilter.html www.unifilter.com/performance-facts.htm

K&Ns are great for airflow, which is what they were designed for. Their original application was on racing engines, where
airflow is important and ultimate engine life was of little consern. They
are not as good at filtering as paper or oiled foam types. (actual date can be found on www.realbig.com/miata/miata/1994-02/412.html)

bc01cls

Uh-oh.................just ordered a K & N. Good news is I'm using a drop in type since those "down spouts" make me nervous driving in the real world. If conditions get too dusty I'll put the paper one in.

spiroh

I dont think you can clean the foam intakes, which means you have to buy new ones every so often. Just stick with the K&N, and clean every 10k miles.

Spiro

moomaster_99

You can clean the foam intakes....

jdl75

You got it. The only safe way to increase clean air to the engine is to add a bigger air box (short of a compressor). There is a natural trade between filtering and flow. If you find one that filters as well, and increases flow, in the same size airbox, call me - you just beat the laws of fizix. Race engines get rebuilt often. Hopefully your CL won't have to.

Dan

I would not beleive what you hear about K&N's not filtering dust well. If my memory serves me correctly, I'm old, we used to use K&N filters in southren California desert racing in the 60's. Also I think K&N makes the air filters for the Apache helicopter.

mrdeeno

yeah, but when an apache helicopter main motor needs to be rebuilt, who foots the bill?

EricL

I had the oiled foam filters on my Weber side drafts, and dirt still got in. So much for the "whole truth". I cleaned, oiled, and replaced them over 10 years...