I recently bought an 88 Trans Am with a Procharger. The car's been set up to handle 15 lbs of boost, and the guy that built her confirmed this is what it would push if the belts didn't slip, everything was optimal, etc. etc.

According to my boost gauge, under normal driving the car's pulling about 10lbs of vacuum. when I nail it, the gauge ramps up to 5 PSI. That's a 15 lb range, but I'm thinking that's not the blower pushing 15 PSI. Granted, I have yet to really "race" the car from a stop and max out the RPM like, in the quarter, but I have gotten on it pretty good (up to about 120mph) and the gauge barely tops 5 PSI. If that's an accurate reading, what needs to be adjusted to get more boost? Do I have bad belts or is there something more to look for here? I'm totally new with these so I apologize if this seems naive.

 

At idle and light cruise you should see about 10 lbs vaccum ( 18-20 inHg).

If the blower is set to 15 psi boost then you should see that close to redline.

On mine with an old vortech supercharger I got about 5 psi at 3500rpm and 10 psi at 5500 rpm.


If you get 5 psi quite low in the rpm range and then it does not increase with RPM then the belt is probably slipping.

 

yeah, that's what's happening. it hits 5 psi early on and stays there. How do I keep the belts from slipping?

 

Cog belts. But thats just my situation and solution. Some guys run 8 rib and 12 rib serps with some success. The absolute fix is always cogs.

 

What am I looking at ballpark for a cog setup?

 

I can only tell you what mine cost $720.00. I had it custom made by ASP Racing. I could not be happier with fit & quality. Mine were custom made since a cog is not a standard option for a Vortech on a chevy engine.

*edit* on a non LT1 engine.

 

You should also beable to measure both the blower pulley and the crankshaft pulley sizes. From that Willie and other users have posted that should give you a close estimate on what your boost should be.

ATI rated boost pulleys can be off. It's fairly common here to see guys with 8-10 lb pulleys only making 5 or 6 lbs of boost.

https://www.thirdgen.org/forums/powe...ey-change.html

 

The issue is definitely belt slippage, had this confirmed at the dyno shop. Talked to the guy who built her afterwards, we're going with different belts and possibly a custom-fab bracket.

The next issue I have to tackle is the intercooler placement. I've read the topic about the twin intercooler setup, that's a little too involved for me at this point. My goal is to simply move the IC to the left or right far enough to free up the radiator intake. The heat levels are simply unacceptable in 85-degree conditions. I just about overheated the thing yesterday with two high-rpm pulls after normal cruising for 30 minutes.