Hy Guys

I try help for my friend.
The car is a octavia rs 2.0 tfsi with k04 turbo.
If i run on wot and i hit 4000 rpm , the n75 duty is 51% and the boost start fall down and little bit later the n75 also 51% and make a big overboost. I make a low duty cycle software for debuging. I change the n75, i check the timing retard, missfire, fuel pressure, afr etc. Everything fine. I upload a log with low duty cycle software (i made this only for debuging). Before 4000 i can controll the turbo , no problem but after 4000 is unpossible.
Sory for my bad english.

Thank you for the help.