I installed a Hallman Pro today using the side nipple to the wastegate and the bottom nipple to the turbo inlet. I have it mounted on the top radiator furthest to the left facing the car. Pior to installation I had installed the heavier spring with the little hole on the side nipple facing the way the diagram had it.

So once down I took a little test drive. With nob fully out I would max boost at 5 psi in 1st and 2nd through 5th could only get 12~13 psi. I gave the nob a full rotation but same problem. Double checked all lines and everything was where it was supposed to be. Any ideas and what would cause this?

 

try cranking another full turn or even two.
If you only turned it down once clockwise (starting from full out) the ball/spring assembly has not yet made contact with the seat inside the mbc.

 

thanks i'll try a couple more turns.