5.9 dakota vortech S-trim blower 11lb pulley setup. .210/.220 .512 lift cam with 110 LSA. And Mopar RT 2.02 heads.

Car makes full 11psi of boost in 1st and 2nd gear. Shifting into 3rd boost drops to 6ish??? And ideas as to what would cause this?

Thanks

 

I would be willing to bet on belt slippage.

 

My 97 GT was down to 8 psi put a new belt on and back at 11psi this time i got a belt one inch shorter and that keeps the tensioner pulled back tighter. And bead blasted my pulley it was very slick .

 

Thanks all, although I think iti would notice a ton of belt material if it was slipping half the boost in 3rd. Bead blasting the pulleys sounds like a good idea. But aren't they steel? Would they end up rusting very quickly? I'm running a "no slip" blower pulley and it's alum, but Pretty sure the factory crank pulley is steel.

Thanks!

 

Are you saying it drops to 6 as soon as it shifts or it wont make anymore than 6?

Im assuming you realize that boost is related to RPM with a vortech

 

I bead blasted the whole pully then masked off the groves and painted it black. The part of the pully the belt rides on was slick as glass the bead blast gives it a rough surface for the belt to grab. Works great.! Be sure not to blast the bore or it will not fit right as in loose.

 

Thanks all, I ended up making an adjustable turn buckle for the factory tensioner. Now I can make it as tight as we want. No more slip!