Wally39

If you remember I am the one who used to have 9.5 lbs of boost with my saleen supercharger and now I only have 7.5
Well, I ordered and put on the larger water pump pulley and new belt. Still 7.5 lbs of boost. Obviously it's not the belt slipping. It's very tight by the way.
Any other suggestions? What about that actuator thing that's on the passenger side towards the rear of the blower? It has a vacuum line to it and a set screw.

stang910

The actuator on the side is the bypass valve. It opens allowing excess air out of the supercharger when the engine is drawing vaccum and closes when no vaccum is present. If the valve isn't closing all the way or is leaking you will lose boost. So this is a possibility. I don't know if you changed anything before the problem, but if the throttle body doesn't open completely it will also drop your boost. If you had a new tune it may not be programmed to open the throttle blade 100%.

Sxynerd

^Yes, also couldn't a bad valve do the same thing?