So, just installed the K&N 57 series FIPK about a month ago. The thing works great, can really hear/feel the added 9hp. However, it's producing an odd noise, kinda almost sounds like a spooling turbo (almost a little whine, as the air is flowing through at normal throttle, almost like there is a leak somewhere). I've checked all the connections and everything is snug.




I don't mind the sound, I can live with it, but just wanted to see if anyone else has experienced this and if it could be a problem. My wife has K&N full setup on her Grand Cherokee, and there is no turbo spool sound.

 

I don't know what it is either but I have the same sound on my 06 5.4 with 57 series k&n as well. its loudest at 1700 rpm or so. like u say its not unbearable but definitely annoying. mine has been on two weeks now so I will be checking clamps and hoses.hopefully someone else will have solution.

 

now if you add the throttle body spacer (don't. only time i'd use a spacer would be on a carb setup) the noise will be even more noticeable. To me it just sounds cool. It should be normal to here some noise, there's no box anymore.

 

Thanks guys. I'm not gonna worry about it.