Figured i'd post this in the noob section

One of my good friends has had this 1.8T for over a year now and it has a boost problem which became worse over time. When under full throttle & boost it will make way too much boost up to the point the throttle plate will close. It will keep doing this making some sort of *wooshwoosh* sound.

On STOCK software the car will already make up to 1.1 bar of boost. The file that was on the car when purchased should request around 1.5 and it makes well over 2 bar (which obviously killed the first turbo). On a simple stage 1 of myself requesting around 1 bar it will shoot up to 1.5-1.6.

What we have done so far to the car:
Smoke test, replaced IC, replaced piping, tried a bunch of N75's, coil packs, spark plugs, it's had three different turbo's, played with the wastegate, checked N75 wiring, fuel pump, FPR, vacuum hoses (all new).

I've also tried a bunch of different stupid attempts at modifying KFLDRL, KFLDIMX and many more maps to try and compensate for this problem but no luck. It will just not respond to any logical changes.

I would have an old vcds log of it laying around still, it just looks like it ignores requested boost goes straight as high as it can go and then the throttle plate will close and this will keep looping. With the N75 electronically disconnected it will make 0.4/0.5bar steadily without problems.

Perhaps there is something stupid we are missing because i've probably spent well over 30 hours trying to figure this out with no luck, we've tried manual boost controllers too just to try and get this boost under control but also not yielding the result i'd like. When searching on the web there are a few more examples of the same problem but never a solution.

Thanks for 'tuning' in.

We have tested this wastegate with a compressor and it appeared to be correct, but we'll double check again. (though problem occured on 3 different wastegates anyway).

All IC piping has been replaced to be sure though but also nothing. It's also just stock piping.

Nope definitely not it's wired up as supposed to be.