Just had it flashed with APR Stage 1. Seems to want lose power after about 5500. I did put a knock off Forge type Diverter on it. I am running the heaviest spring 18-21lbs and a washer in it. Tuning problem with it? I can here it whistle and it is popping off fine. Pulls very strong now in comparison to stock though.
Is the low end of the Spring Boost Rating its Hold and the High its spike? I need clarification on this. Kinda new to the Turbo stuff. Came from Old school V8's and Stroker Air Cooled Dual Weber 64 VW Bug.

Is 5500 -6000 about it maybe and knocking on the rev limiter at the Redline or the Diverter not holding boost enough up there?

Red 2002 TT 225. APR Stage 1 and Diverter. Going going for Muffler Delete axle back soon.

 

That's typical. Your K03 turbo is pretty small and runs out of lungs before redline, so that dropoff at higher RPM is to be expected.

 

225 with a K04 by the way. No answers? I guess I will have to call the guys at Bpb Hindson here in KC to see what they suggest.