turbo leak exhaust side?

[Takjack]

Hi i have been having some issues with my turbo, it now spools around 2200rpm instead of 1700 back when it was running good. when i tromp on the throttle it hesitates then takes off with a big black cloud of smoke, decided to do some investigating and saw black smoke coming from my turbo area (couldn't really see from where exactly) Just wondering if there was any spots to check first that break more often. VW told me my whole turbo needed to be replaced but could not tell me why, they said they were getting turbo codes so it need to be changed. TBH the dealership i have been going to are horrible to work with and wont tell me anything. I was told it might be the waste gate sticking, does the waste gate release the intake or the exhaust side?

06 jetta tdi 1.9 brm

thanks a lot

[Seatman]

Sounds like a leak, could be the vacuum lines needing replaced or maybe the egr flexi pipe that runs from the exhaust manifold to the egr is cracked.
The turbo in your car uses vacuum to make boost rather than have a wastegate to allow excess boost to escape so any tiny leaks on the vacuum system will cause the turbo to spool late as it needs to create extra vacuum. Same for any leaks in the exhaust before the turb like the egr flexi because the turbo needs the gases to spool up.