Hello all ,I had a prob with my standard turbo so i fitted another all fine but now there is a slight knoking noise in the engine the car had sat around for 6 months and i thought something was sticking because the noise got better when i gave it a small carefull run to the garage,I am certain its only running on 5 so i took the compression off each cylinder and the results were no1, 130psi 2, 5psi 3, 142psi 4,122psi 5,132psi 6,122psi my questions are what is the compression supposed to be with standerd pistons and how do i no if its the piston or the valves on no 2 being only 5psi which obviously isnt right your help would be appreciated :cheers: Trev