powerdyne S/C question

[silvrsvt]

my buddy has a fox body mustang with a powerdyne and it will only make 6lbs of boost no matter what pulley he has on it.. with a pulley for 12lbs it made 275hp 375ftlbs the car is running pretty rich but still should make more boost right?? he says it hits about 6lbs at 4500rpm and them goes down to about 5 by redline. I told him to see if the belt was slipping but he put a brand new one on and made sure it was tight.

what do you guys think could be the problem?

[ASUSMC]

Is it blowing the rest of the air off somewhere? Check for a vacuum leak.

[silvrsvt]

he says he doesn't think it has a boost leak but I am going to look at it tonight

[QuarterHorse]

First off...have you put the car on a dyno? With the supercharger air/fuel mixes will be completely different from before the supercharger was added. You said the car is running rich is why I ask. Tuning the car will help. Another possibility is the belt inside the supercharger is slipping. The Powerdyne was notorious for belt and bearing problems. I have one on my 88Gt and it happens to be in decent shape but I need to find someone who can do the bearings for me. I have not had the car back to the dyno to see what improvements there are. I run an 11lb pulley and it definetly makes a crapload of boost. We started with 206hp at the wheels before so we'll see what happens. Anyways you need to do some checking on the Powerdyne. If it's a well used unit I'll bet your problems are there.

[QuarterHorse]

And checking vac*** to the bov is important. If its not working it will vent boost.