Tuna Man

They did TWO different test on the K&N/AFE72....Course AND fine dust. Although they should of tested ALL filters with both medias.

SemperFi-sh

i made no claims of being a scientist, i was just saying that you can erode your turbine blades if you dont have a good seal on your K&N....

that is all, carry on...

xl883lo

[quote]Tuna Man (5/17/2008)Exactly.......and I would have no evidence they "cheated" but it is a "classic trick" for this test and I suspect they did test the all with fine dust and didn't like the result. A dirty air filter(but not clogged)is actually a more efficient air filter than a completely clean one due to a thing they call "dirt cake". A build-up of coarse residue on the filter acts like a prefilter and actually increasesit's filtering ability . Coarse dust is a very poor representation of real world conditions unless you are running construction equipment or racing offroad. Some heavy equipment companies like Caterpillar have designed their filters to take advantage of the "dirt cake" effect. I alsothink ISO 5011 actually specifies that you should use fine dust for automotive engine testsand especiallywith diesel engines. Now one can make the argument that the OEM filter is better because it takes advantage of the "dirt cake" effect and the K&N filters which are either a cone or a classic ring are not really designed to do so. But the reality is in the real world unless you are chasing bulldozers and earth movers eight hours a day you will likely never be able to take advantage of the difference.

Here is a little blog for you to read that might be interesting.

http://autoengineer.wordpress.com/

I also tried to link the Caterpillar site but apparently it is down. They have an interesting piece about their standard and high efficiency air filterswith respect tothe "dirt cake" phenomenon.

xl883lo

Would this not be true of any filter??????

Tuna Man

Found this...Thought it interesting about FACTORY ie Chrysler has a performance air intake kit using K&N.

"In the U.S. Chrysler markets factory-approved performance kits for some of its truck engines. The kit includes a K&N filter and the kit's use is covered under the factory warranty. Chrysler would not offer a kit such as that if the K&N Filter could not meet OE filter efficiency goals."

http://www.mopar.com/street/whatshot1000.htm

"In Japan Nissan markets similar factory-approved performance kits for a couple of models that are offered only in the Japanese domestic markets. Like the Chrysler, kits, the Nissan kits include K&N filters."

http://www.vettenet.org/knfilter.html

Keep in mind I haven't ever used a K&N filter....so I'm NOT on the bandwagon for them. Trying to get the FACTS and experience from others.