Try and take a video and post it... Maybe it will pick up the noise you are talking about..

With video im sure someone could point you in the right direction.

I will get a video tomorrow.....

Here is a video

http://media.putfile.com/M90-noise-

I see the BCS in the vid has the end with one vac port is empty. There should be a vacuum line running from that port to a port on the nearest vacuum tree that taps in post-rotors. Your BCS can't work right without that vacuum line.

I had the line plug ed to see if it fixed my low boost problem...

Where is the best place to buy a BCS.............

Toss a post in the Wanted section. There'* been a large demand lately..but someone has a couple laying around.

Still need help.... Ive replaced The BCS BCA and now the car drives worse then before...
It drove perfect when I bought it... 10 psi and very smooth , now about 7-8 psi and is just embarrassing to be seen in....
Now it has the check engine light is flashing (new after the BCS) and it has a terrible stumble when accelerating(its worse then it was when I installed the BCA), and now it also is making way more noise.....

All vacuum lines that where broke have been replaced and all routed correctly....

Help.........

Where can you purchase a scan tool and how much do they run as far as price???

How much play should the snout pulley have??? when I turn it back and fourth it has about a half inch of play, no play in and out. When I start the car with out the sc belt on, all my noise issues go away???