Hello, I bought a tuned  Superb  last year rated at 480Hp.  After a session at the track,  the turbo started to  whistle so  I sent it for reconditioning.  I  mounted it back on to the car , set the wastegate actuator voltage to 3.5V with the VCDS  , but the car is not reving up over 1800-2000rpm

No errors on VCDS.  What could it be?

 

Wow are you tracking it? I thought you already sold it.

Are you trying that revving when stationary? Many of these cars have a low limiter when not in gear.