I just installed an HKS downpipe. My only other mod is an apexi intake. I'm hearing a whining sound from the lower (closest to the side of the car) intake cone. This one was not removed during the installation of the downpipe. There is no leak at either end of the downpipe. So what makes the noise? The car is running fine, otherwise.

 

what kind of whining

 

It's not that loud, but it's high pitched.

 

Turbo spool??? Or is it at idle??

 

since you installed a downpipe you may be hearing the turbo. does the whining noise sound like a vaccum cleaner on steroids?

 

I can only hear it at idle. The sucking of the intake drowns it out when any throttle is applied.

 

Does the pitch of the whine change with rpm? I have a high pitched whistle type noise after 4500k rpms that I've never been able to cure.

 

Never mind, cross postings.

 

there could be a little hole in the intake somewhere
my best advise: when you hear the noise get out and pop the hood, itll be easier to find

 

I did pop the hood. That's how I was able to narrow it down to the intake.

 

oh ok, thendid you stick you hand on it to feel if there was a hole, or put your ear up to it?
if theres no hole, then it could also be an internal component rubbing or have a bad bearing.