Boost leak or broken boost gauge?
Thread Starter
Registered User
Joined: Mar 2008
Posts: 1,583
Likes: 1
From: Morristown, NJ
Hmmm I will try tightening it even more than it is. I can barely turn the belt 90 degrees, which I hear is a good tightness. I'll check the belt again, and try measuring the deflection.
Registered User
Joined: Jan 2006
Posts: 144
Likes: 0
If it's boost leak, you also may not see full vacuum at idle. I just fixed a leak of my own at the tee for my boost gauge. I would go from 10 in. Hg to about 5 psi. After I fixed the leak, I now see 20 in. Hg to 10 psi, and she feels right again.
Thread Starter
Registered User
Joined: Mar 2008
Posts: 1,583
Likes: 1
From: Morristown, NJ
Hmm thanks for the tip. I need to double check what my vacuum number shows at idle. And I'll double check the tee at my boost gauge, though I haven't messed with that at all.
Registered User
Joined: Sep 2009
Posts: 1,696
Likes: 1
From: NY/MI/TX/S.Korea
Originally Posted by Irvatron,Jul 9 2010, 08:22 AM
I bet the belt isn't on tight enough, you should have about 0.25 inch deflection pressing on the middle part of the belt between the Sc pulley and crank pulley - it needs to be super tight.
When i had my car on the dyno the first time it would get to around 6500RPM @ 4psi then the boost would drop off - it was belt slip.
I have my vacuum gauge tee'd at the same as you.
It should gradually build up in boost and be around 6-7psi when nearly at the redline (some gauges dont read 100% accurate but should be there abouts), it should read vacuum in partial throttle 20-30 Hg.
The only other thing is to try and listen for belt slip (quite hard) and drive it at a constant high revs and see if it dips off.
When i had my car on the dyno the first time it would get to around 6500RPM @ 4psi then the boost would drop off - it was belt slip.
I have my vacuum gauge tee'd at the same as you.
It should gradually build up in boost and be around 6-7psi when nearly at the redline (some gauges dont read 100% accurate but should be there abouts), it should read vacuum in partial throttle 20-30 Hg.
The only other thing is to try and listen for belt slip (quite hard) and drive it at a constant high revs and see if it dips off.
Registered User
Joined: Mar 2010
Posts: 523
Likes: 0
From: Minnesota
I have the same issue. I am suspecting belt slip also or possibly the gauge. I have a different brand belt though and I think thats what might be causing it for me. Eitherway I only have the stock pulley and I can differently feel the car going faster than N/A so I'm also checking my crappy gauge.
Thread
Thread Starter
Forum
Replies
Last Post