I'm having trouble finding the source of a whistling (not whoosing) noise after I installed an M2 airbox. I installed intake hard pipes at the same time. Basically it makes a whistling noise at -250mm to -300mm. The noise is similar to air blowing by jelousies (?sp) in a high apartment building. So, it only does this under light throttle. Boost pattern is perfect, there is no whistling/whoosing under boost.

I sealed all the edges of the box with silicon sealer and made sure all clamps are tightened down.

So far I can only think of two things it could be, my primary turbo hard pipe is not perfectly aligned with the airbox (1/8 inch off). I dont think this should matter because the coupling seals the connection.

Also, I looked at the airbox, and the hose connection on the box on the upper right hand side of the box has a small hole (~2mm). In other words, the hose connects to the airbox, but the inlet is very small. I was wondering what the reason/function of this is, and if its possible it could be causing the whistling noise.

 

Disconnect the air pump electrical connector and see if the sound goes away.
Might just be the discharged unneeded air from the pump. If this is it, then you have the option of drilling out that small hole but then you would have the famous moo-fart sound, your choice.

 

Ok, Ill try drilling out the hole. I don't mind the mooing as much as I do the high whistling

Thanks

Ryan

 

Ok, looks like he was right. I tried drilling out the small hole, and the whistling sound went away. I drilled it out to maybe 1/4" and the car has little to no "mooing"