I've noticed this ever since I've had my mini, so I thought I would ask about it. I've got a pipercross intake/CAI and I can hear a high pitched whistle coming from it any time I'm on the gas around half or 3/4 throttle. Is this morning for a CAI? I'm assuming that the intake is louder...so you are going to hear the air rushing through the filter?

After watching my boost gauge, it seems to happen even if I'm not building any boost....it's just when ever the throttle is around 1/2-3/4 open.

Anyone else have this problem? It's kind of annoying sometime.....just a little high pitched squeal.

 

It happens if you have an intake, if I remember correctly it's your BPV that makes the noise, and it's just air rushing through. It's normal, there's nothing wrong with your car. It is annoying, but I don't know I either accelerate through it, or drive above(or below) the speed that would require me maintaining the pedal at that position

 

The VGS mod might help. Getting the valve to close a little earlier and more positively might cut down on the noise.

https://www.northamericanmotoring.co...ystem-vgs.html

 

I already have a Detroit bpv

 

With the VGS?

 

I've thought about doing the VGS mod, but from what I've read....and based off of how the entire system works.....it seems to me that all that's going to do is keep the BPS closed most of the time...building boost all the time, building more heat, and killing fuel MPG.

I'll keep my DT BPV and live with a little whistle I guess

 

The high-pitch suction noise is normal with most of the aftermarket CAI kits. It can be more pronounced depending on temperature and/or humidity outside as well. Best advice is to look for videos to compare on Youtube or take a ride in someone else's MINI with a CAI kit.

 

Will also be more pronounced if you have a pulley and if you removed the plastic air dam behind the air box.