Hey guys I am trying to get to the bottom of why my car performed so bad on the dyno. All I can think of is my chip, or belt slippage. I have the normal dusting around the inside of my pulley but how can I be sure my belt is or is not slipping for sure??? Thanks for any help you can give me.
How to tell if your belt is slipping??
- Thread starter venomus 03
- Start date
If you were on the dyno your A/f would go high because of the reduced load. You should also see increased belt dust.
What size pulley and belt are you using? Are you using idlers?
What size pulley and belt are you using? Are you using idlers?
I have a 2.81 and I did not install the pulley or the belt.(Bought car that way) It has some dust on the pulley and a little on the pulley cover but nothing to crazy. A friend gave me two pulleys that are direct replacement of the lower two idlers cause he did not need them. Do you think those are worth installing or not without the main idler on top?? Thanks, you guys have been a big help in getting to the bottom of this. The a/f was a little high at 3500 rpms being 13.2 and after that it was 12.0 all the way to redline. What do you think?
definitely worth it
m.
m.
I don't think the lower pullies will help your belt slip problem unless your belt is very loose. Where is your tensioer? Left, middle, or right?
Can you post pics of your dynograph? If your tune is done right it's sounds like your a/f problem is due to belt slip. You shouldn't be pegging the MAF or running out of fuel pump at your HP levels. If I were you I would get an idler set and a new belt. Clean up all the belt dust so you can monitor any new dust.
Can you post pics of your dynograph? If your tune is done right it's sounds like your a/f problem is due to belt slip. You shouldn't be pegging the MAF or running out of fuel pump at your HP levels. If I were you I would get an idler set and a new belt. Clean up all the belt dust so you can monitor any new dust.
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Look for belt dust under the blower snout. If you see dust you're getting belt slippage.
The tensioner is a little to the left from center. There is dust on the pulley, pulley cover. and a little all over under the snout. The a/f is only high untill roughly 3,500 and them it straightens out. I dont have a cam for the sheets unfortunatly.
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OK. Here is my opinion on belt slip.
first, I have a 2.75RR and 74 gates, no idlers yet (just ordered). as wee know this setup should and does slip.
Just by the feel and looks of the boost gage I would have NEVER noticed belt slip. It pegs the stock (shitty) gage and does not fall off. The car run real strong and does NOT seem to lose power over 55000rpm.
I did NOT see much belt dust either.
so bottom line, the only way to KNOW about your boost drop-off is too hook up onto a real gage. On a real gage on the dyno my car on showed 11 pounds. We all know with no slip I should be seeing 15+.
first, I have a 2.75RR and 74 gates, no idlers yet (just ordered). as wee know this setup should and does slip.
Just by the feel and looks of the boost gage I would have NEVER noticed belt slip. It pegs the stock (shitty) gage and does not fall off. The car run real strong and does NOT seem to lose power over 55000rpm.
I did NOT see much belt dust either.
so bottom line, the only way to KNOW about your boost drop-off is too hook up onto a real gage. On a real gage on the dyno my car on showed 11 pounds. We all know with no slip I should be seeing 15+.
If you're running it with the pulley guard, pull that out and check for belt dust. I doubt that slipping alone is going to cause major dyno fluctuations. I was using the stock belt with a 2.80 upper pulley, and while slipping you can feel the lost power, almost like wheel spin, and when it grabs it pulls hard again. Since then I have put a smaller belt, w/ the tensioner being ideal (in the middle) but still end up having belt dust in the area. Best way to get rid of slip is in the idler pulley! 
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