There seems to be a debate about K&N filters vs. stock. Everyone seems to agree that K&N flows better. The question is filtration ability....so I did a little test. I drive between Santa Barbara and Bakersfield 2 times per week. It is a brutal gusty dirty air drive that is 300 miles round trip. I used a stock filter for 3,000 miles...then used a chemwipe to collect dust particles that made it thru the filter and were inside the airbox. I did the same with a K&N filter. Again it was for 3,000 miles. The chemwipe with the stock filter collected approx. 360 particles of very small size in 3000 miles. The K&N filter collected 267 particles of very small and small dimensions. A few of the K&N particles were slightly larger than anything I saw with the stock filter. (Very slightly) I used a dissecting microscope to collect the particle number.

Great experiment Doc!

Although none of my Benz are equipped with a K&N, I believe in the product. I started using them almost thirty years ago when I raced motorcycles in the dirt.

There are many posts that I see that indicate that many of our friends who log into MShop feel that the advantage to a K&N is that you no longer have to purchase air filters. This is NOT the advantage to the K&N, it flows better and traps more dust.

Your experiment was great, I love such scientific study. I am surprised, that there was only about a 10% difference. Was the K&N freshly cleaned and charged?

Thanks for sharing your results with us,

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Larry Bible
'01 C Class, Six Speed
'84 Euro 240D, 523K miles
'88 300E 5 Speed
'81 300D Daughter's Car
Over 800,000 miles in
Mercedes automobiles

yep...started with a freshly oiled but very well-used filter. The driving conditions appeared similar too....I wish I could actually measure the particles, then I could be certain...I agree the filter doesn't really save any money....it flows better ,and I feel holds up better when conditio

i use a k&n airfilter also. they seem to help in the upper rev preformance quite a bit. you should try your test with a dirty K&n it says on the box that they work better when thier dirty. thier theory is that the old dust particles become saturated with oil and become part of the filtration medium, thus improving filtration.

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87 300E
BLACK GOLD WITH CREAM INTERIOR, SPOILER, AIRDAM
CLEAR MARKERS

87 420SEL
BRONZE WITH CREAM INTERIOR