K&N Air Filters

[Domman56]

Who's using them
Who's not

if not why not

[Piwoslaw]

Please use the search engine or look around first. K&N filters have sprung up here quite a few times. Please do not multiply posts when you don't have to.

[Daox]

Nope, I don't use em. It doesn't help at all if you are driving to get good mileage. Plus, they let more crud through the filter and can gum up MAF sensors with the oil from the filter.

Testing to prove it:
Testing a 'performance' air filter for MPG - Part 1 - MetroMPG.com
Testing a 'performance' air filter for MPG - Part 2 - MetroMPG.com

[Mustang Dave]

Originally Posted by Daox

...Plus, they let more crud through the filter and can gum up MAF sensors with the oil from the filter.

I have over a mile of dusty dirt road between my house and the nearest paved road. I tried a K&N on my truck for a year. There was no difference in performance or economy. When I checked the filter, I found dust in the filter housing on the "clean" side of the filter.
I'll stick with OEM paper filters.

[mcrews]

I can't wait to get my ECOMODDER.COM window stickers......I'll get 2-3 mpg AND 10-15hp just by puttin the stickers on!!!!!!! yuck yuck yuck!!!

[Christ]

If you want a cleanable filter that doesn't gum up MAF sensors, and has no potential issues with diesel engines, get one from AEM or Fram. They're cotton gauze material, washable, and don't require oil.

K&N filters aren't any more environmentally responsible, either. You're using soap which contains phosphates to wash out the dirt/grime/oil that is going down the drain into the public water supply, making it even more difficult to provide clean water, or further poisoning your local water table in the event that you're using a well.

Farmers out here will tell you that one drop of oil will contaminate 1,000,000 gallons of water. It's not to a harmful level, but the point is to be very aware of what you're doing.

Wash that filter out, and you're doing just as much harm as you would be by throwing that paper filter into the landfill. Where's the logic?

There's a reason that K&N doesn't make these claims on their own... they rely on fanboys to make the claims for them.

[bondvagabond]

He says in his research, that at wot it might be more efficient than stock paper. Do some of the pulse and gliders use wot? would a air intake different than a geo metro negate the test results and maybe make a k&n worth wild? I sure don't like to whole allowing dirt in thing though.

[Christ]

WOT is normally a very bad situation. In ECU-controlled cars, enrichment happens, and the AF ratio is richened to the point where it's no longer being efficient. 80% seems to be the max throttle angle.

In carb'd cars, it just opens an enrichment circuit which is normally uncalibrated to a specific AF ratio, and dumps some fuel in there unmetered to aide in cooling the engine under high load.

Again, 80% (depending on carb config) is usually about the cut-off. In either event, K&N still doesn't make any of these claims on their own.

[MadisonMPG]

These threads should stop now.

[Domman56]

well I've always used them and never had any problems, then again only one of the cars in my family have a MAF We usually drive older cars and they always have helped in fuel economy. Helped in all of my friends cars too you just have to make sure not to over oil them