compressor surge, sucks hey!
My nissan RB20 had the worst compressor surge when a hi. flowed/crossed bred turbo got fitted. I tried all things to stop it from changing intercooler pipes, by-passing the intercooler and the turbo shop even changed comp wheels and other stuff. In the end i changed to a off the shelf turbo and no more compressor surge. Your problem will be a missed mached turbo combo of some sort. Try changing all the parts in the enginr bay and you won't fix it- i think you should get a different turbo.Your turbo will probably work fine on some other engine just not yours, much like mine did.