Hey guys, gotta question about a sound. Today I was driving through a tunnel and I heard a noise I've always subconsciously heard but never this clear... and now I'm addicted! Whenever I shifted, it made this "airy" noise, like blowing. It was only when I shifted though. Is this a CAI or a BOV sound? I don't think MINIs come with BOV stock... so I'm guessing it's the intake??

Could someone help me identify this noise? I want to be able to hear it every time I shift, under a tunnel or not!

What benefits would a BOV make?

 

It's the diverter valve. The mini does not have a BOV.
Redirects turbo backpressure to the intake side of the turbo.

BOV releases excess boost into the atmosphere while making the psssttt sound.

The DV does make some sound and becomes more apparent when you install a CAI and remove the sound blocker in the intake.

Get a DoS intake and it becomes really loud.

 

I was just looking at the Alta CAI, and I think I'm going to go with this. I looked on youtube and that sound that you described is more prominent with the intake, which is just what I was looking for. Thanks for your help.

 

DoS is the only true CAI for the mini.
I would go with the DoS, but you can do as you please.

 

DoS!!!!

 

The turbo noises are super loud with the ALTA intake.