K&N filter - noisy? - Diesel Forum

philhyde · 08-13-2009, 08:11 PM

Sorry if this has already been posted. I could not find anything using search.

My 2006 F250 has a K&N filter on it. I am hearing a very distinct whine/flutter at low RPM's that seem to be related to the speed of the turbo. If I didn't know better, I'd say that the K&N is not dampening this noise, wheras the factory intake would.

Is this typical of the K&N?

Thanks!

champelite210 · 08-13-2009, 08:26 PM

You are correct. I had a AirAid on mine when i first bought it. I put the stocker back on. Yours is probably the open type that just fits on the end of the tube. You need one that has a box with a lid to help quiet the air.

**bugman** · 08-13-2009, 08:48 PM

If you are not running a lot of extra horsepower you would be better off putting the stock filter system back on. It was pr oven a long time ago that it is the best filtering system for a stock or slightly modified truck with the 6.0 engine.

philhyde · 08-13-2009, 08:51 PM

I have the stock filter system and fully intend to put it back on. The K&N filters make me nervous anyway. I guess I should explain that I purchased the truck with the K&N filter on it already.

tinkerr · 08-14-2009, 04:11 AM

I've got K&N style filter on my 99 and you hear alot of turbo noise. the wife says would you take off already dam thing sounds like a jet.

philhyde · 08-14-2009, 07:46 AM

To be clear, this is not the high pitched turbo whistle, but rather a lower pitched sound that is like a harmonic frequency. It is around 1000-1200 RPM.

lubbockguy1979 · 08-14-2009, 01:19 PM

The oiled k&n filters and other dry filters have caused a lot of dusted turbos on the 6.0 specifically. People have had warranty claims denied specifically because of aftermarket filter systems. The after market filters do not filter as much dirt out. Ford claims the donaldson unit (stock intake) to be 99% effecient and donaldson claims 97%. On top of this the aftermarket filter system starts to provide gains over stock and close to 3000rpms which on a stock truck or even mild mods (tuner, exaust, small turbo upgrades) will be out of the trucks actual powerband. The stock unit is capible to around 550-600 rwhp and does a better job of filtration.

philhyde · 08-15-2009, 03:53 PM

Today I replaced the factory air cleaner. The whining noise that I was hearing is still there. I guess I'll have to record it and get some feedback.

The truck does seem to drive better with the factory filter on.

philhyde · 08-15-2009, 03:59 PM

This description of a "siren" seems to fit the noise I'm hearing. Yikes!

Turbo whistle to turbo siren "New Findings"

350r powervalve · 08-15-2009, 08:41 PM

philhide i want to tell you about my friend who has an 04 6.0 and a test by a tech at the dealer on the air going in to the motor with the k/n verses stock and the air with the k/n was 200 degees, i beleive hotter than the stockers because the engine was sucking all that hot air off the motor. i beleive he put the stock one back on and his problems went away.

lubbockguy1979 · 08-16-2009, 08:55 PM

i used to have a noise that was a siren sound that was intermitten and the only time i noticed it was under acceleration. i first tried replacing ic boots to no avail i ended up getting a 08+ degas bottle cap which fixed the noise completely. it cost me less that 10 bucks at the dealer

philhyde · 08-16-2009, 09:21 PM

This is the noise.

YouTube - 2006 Ford F250

champelite210 · 08-17-2009, 02:12 PM

Could be like an exhaust drone. Does it have an aftermarket exhaust? Maybe the down pipe vibrating off something. Check your exhaust clamps for tightness. ???? I'm just throwing out ideas.

philhyde · 08-17-2009, 02:13 PM

Dealer confirmed the noise is coming from turbo. So it's either a replacement or some kind of repair procedure (writer did not elaborate).