...my mate has a golf mk4 gt tdi 130PD and his boost is 32psi peak boost...
Is this a standard turbo?
If so, I would suggest to your friend that either his boost gauge is way off, or his remap is shockingly poor causing his turbo to massively over-boost and I wouldn't expect the turbo to last very long. The standard GT1749VA will not produce that much boost.
...mine has been remapped to 163bhp. His golf was not getting left behind at all, which has lead me to believe something isnt right. I should be able to easily pull away from him. I had the engine management light come on, and the error code read was high boost or something similar. It went off itself. I have been told it could be the boost sensor or something? The turbo sounds ok, doesnt sound out of place
The most common error code to appear for overboosting is "boost charge control - positive deviation". This is caused when the vanes in the turbine side (hot side) of the turbo stick slightly instead of operating freely to control the amount of exhaust gasses passing through the exducer.
These vanes get a build up of carbon over time restricting the movement and as a result too much exhaust gases are directed to the exducer, causing it to spin the shaft, which in turn spins the inducer too fast creating excessive amounts or pressure (boost) and overloading the system.
It could also be caused by a poor remap (N75 map poorly written, irregular boost control etc...)
Now, what can you check?
Depending on how mechanically minded you are, you can test the vanes by moving the actuator arm on the turbo to see if it moves freely or is stiff. This would confirm sticky vanes or the all clear that end.
VCDS log your drive to looks for irregular boost patterns or surging.
