Not making boost.....what could the problem be?

BlackFox5.0

Founding Member
Aug 7, 2000
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Massachusetts
I put in my a-trim and took it for a test drive, I have a boost gauge with vacuum, and when I get on it, the vacuum goes up to 0 holds, then goes up to like 1-2psi around 4000-4200rpm.

I've got a power pipe, a 6" crank pulley, and a 3.12" blower pulley.

Shouldn't I be making boost much sooner? What could the problem be? I have the belt on not extremely tight, but it's on, I just pushed down on the pulley and tightened it up, I didn't use a wrench (should I have?) How tight is the belt supposed to be? Should it be really cranked on there? With virtually no play?
 
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I tightend up the belt and it's still not making boost soon enough, it comes on around 5000rpmish. Shouldn't the boost come on a lot sooner? In first gear, when I ease it up into the rpms (so as not to break the tires loose) the car died like I hit the rev limiter.....

I still have 87 octane in my tank and my Autolite 24s are still at .050, I was going to change them but it started pouring out.....I don't see how this would affect my boost though. Timing is around 13* I think.

I plan on gapping my plugs to .034 ,and backing the timing to 10* and filling up with 93

As of now my car feels no more powerful than before.....
 
The belt needs to be pretty tight. I use a torque wrench and and a 1/2" extention and put it in the square hole on the adjuster. I set mine on about 90 ft.lb. Try tightening it up and see how it does.
 
BlackFox5.0 said:
I put in my a-trim and took it for a test drive, I have a boost gauge with vacuum, and when I get on it, the vacuum goes up to 0 holds, then goes up to like 1-2psi around 4000-4200rpm.

I've got a power pipe, a 6" crank pulley, and a 3.12" blower pulley.

Shouldn't I be making boost much sooner? What could the problem be? I have the belt on not extremely tight, but it's on, I just pushed down on the pulley and tightened it up, I didn't use a wrench (should I have?) How tight is the belt supposed to be? Should it be really cranked on there? With virtually no play?
I have a 92 LX w/ a Procharger 9lb boost and an 3 core intercooler. I don't see full boost until i'm close to 6000 rpm's. According to the speed shop, this is normal. I run Autolite 23's gapped at .030. Car runs fine. Definitly get rid of that 87 octane. Detonation is very bad for a blown application. Remember, the faster that pully spins the more boost it will make so it stands to reason the higher the rpm's the higher the boost.