mojogoes said:
You do get churping on the waistgates but this sometimes means it needs cutting back on the exhaust side, but this being a vnt sounds like it could be the bearings have you lost any oil check in the intercooler.
How exactly can you get chirruping on the wastegate? The wastegate opens
on boost to control the boost level and stop the turbo blowing itself and the rest of the engine to bits. When you lift off, boost drops and the wastegate slams shut - if it does anything else it's fecked. Any noise you get from the wastegate would be on-boost and would be a whitstle or similar noise of air passing through it. No chirrups, squeaks, pops, bangs or whooshes.
The dump/divertor valve opens when the throttle is closed to give the trapped boost somewhere to go, but they whoosh if you can hear them at all.
If the car makes compressor stall noises then maybe the DV is stuck closed?