I have a 2012 R56 cooper S with a ALTA CAI and Hot side Tube, which I took in last week to have its oil changed, turns out that my break sensor was off so they had to update my software which took about 5 hours. Ever since that day my car will make a loud sucking noise SOMETIMES during a cold start. I've had it not happen during really cold nights and happen to me on warmer mornings. So what happens is when I turn it on it sounds almost like when i step on the gas and i can hear the air rushing in my intake, but when i even slightly step on the gas it sounds like my BOV is going off (so pretty much the opposite of what it would do while driving). The other thing I noticed is that during a cold start my pressure gauge reading would be low (wastegate stays open during warmup) but while this noise is going on my pressure is almost where it would be while im accelerating during a cold start. The noise will go away pretty quickly and my pressure drops to where it usually is until its warmed up and its all normal after that..........im taking it in next week since its still under warranty and they touched it last but i was just wondering if any1 else has noticed this or has any thoughts?

 

Did you ever figure out what the problem was? I experienced that same issues after the software (5 hours long) was updated from the dealer...

 

Yeah I ended up calling the dealer, the software update actually has the car spool the turbo on a cold start to pump hot air into the engine. This seems to only happen on rather warm mornings (i haven't seen it happen when it was below 50F but I'm not sure what the cut off temp is)

 

Great, thanks for the info!