MBC fitted - now got a chattering noise on boost

Hi All. I fitted a turbosmart gated boost controller at the weekend, and am running boost at 13.2 PSI on my '95 850 T5. Trouble is, I've noticed a chattering noise whenever the turbo is on boost. Is this bad? If so, how do I remedy it? Any help would be gratefully accepted!

no expert but if you aint got a dump valve its probably wastegate chatter when i fitted my in car booost valve wen i opened it my wastegate chatter got a hell of a lot louder since fitting dump valve chatter is sort of drowned out by the wootoosh of DV no expert but sounds like ye olde wastegate chatter y yes wastegate chatter indeed lol :)

turbo chatter comes the turbo blades coming to a quick halt when boost pressure isnt dumped... i have no idea why you would be chattering whilst boosting.... but i would be concerned

the noise sounds kind of like a cheap clockwork toy if you catch my drift - it sounds like it's coming from underneath the centre of the dash so that would equate with the position of the turbo and wastegate on the other side of the firewall - The funny thing is that it doesn't change according to level of boost - doesn't get faster, change pitch or get any louder. If this was chatter from the turbo blades surely it would be different the more boost it gave? regards, craig.

Just a thought - could the spring on the wastegate actuator be too weak and not closing the actuator properly, car has done 116,000? Is it worth shortening the rod by a turn or three, or do you think it's unlikely to be that?

It could possibly be the wastegate being slightly loose and rattling, or how about the ball bearing inside the MBC rattle? Just a couple of suggestions. Andy P

Pinking sounds like a crisp packet in your engine, I would say its your wastegate chattering due to the MBC opening and closing/hunting. Wip the MBC off and see if its cured. How long has the MBC been on , they do take a while to settle. If it's a ceramic one they can take a while to bed in and some air can leak past and cause the chattering.

Ahh, right. the MBC was fitted and set up on saturday. I worked out how many clicks of the dial gave how much boost, and after the last run giving me 12.6PSI, after I stopped the car I clicked up anothe two notches so it would run 13.2PSI then locked the boost valve. The noise started next time it was driven, so it may just be something going on with that setting and the wastegate. I'll let it settle down and see what happens. Don't fancy the idead of taking off the MBC as that would result in unregulated boost! I don't think it's a ceramic one, it's a turbosmart gated system.