car is an s2 erst, it has been tuned by power engineering, i bought it to work in and it has been mucked about with. cars running a t34 and boosts to just over 1 bar.

now the problem im having is not in 1st and 2nd its fine, 3rd 4th and 5th however it will only make it to 4000rpm before bogging down and not making power, the turbo spins up but just wont make any more power. anyone got any solutions?