my 95 riviera i am only getting 4psi boost out of my car with stock 2.85" pulley. i add the 2.55 and i get 7psi. i have new belt and tensioner. new coupler and oil. Cool air intake. Tr55 plugs gapped to 55.

i have checked my vacuum lines and no leaks. i removed the bca upper vac hose and boost didnt change. i used to get 7psi with stock poulley but not anymore what else could it be.

could it be the check valve on the vacuum line going to my transmission modulator.the only thing i havent checked is fuel pressure. i put a new fuel filter about 8k miles ago

What are you measuring boost with? Riv'* don't have gauges. Whatever you're using, do you trust it?

Coupler, oil, intake, plugs, and fuel pressure have nothing to do with how much boost you'll get.

Belt slip, vacuum leaks, and boost leaks, as well as inaccurate gauges will all be possibilities.

Or another possiblity is that your PCM is limiting boost for another reason. Do you own a scantool? (I'm betting not yet from your previous posts and my PM'* from Slug).

i got a scann tool. im waiting on the cable from slug. i have a vacuum/boost gauge which i T'd inline with the fuel pressure regulator like the directions told me to. i read anywhere from 16-19 on vacuum at idle and 10-15 while cruiseing at 60mph and 1500rpm

How is this different from these 2 threads?

http://www.bonnevilleclub.com/forum/...er=asc&start=0

http://www.bonnevilleclub.com/forum/...hlight=#943782