i have a fiesta rs turbo 1991 and have noticed that its not as fast as it used to be, i put it down to the clutch slipping. i now know that thats not the case and its only boosting at 4 psi were as before it was boosting it 10 psi. can i adjust the boost myself or is that for a profesional? also wot would cause this to happen i have checked the 2 pipes cumin from boost controler and these seem fine.
any help/advice would be very appreciated.
thanks kieran