Possible Belt Slip / Boost loss Whipple 3.0

[03cobra#2]

Putting the finishing touches on my project. Whipple 3.0 with a MS3 PNP. Car starts, idles, and drives amazing. I data logged a couple WOT pulls on the highway today and noticed boost comes on at about 25, almost 26 lbs, and holds until about 4800 rpm then slowly tapers to about 20-21 by the end of the pull (6,800 RPM). Thinks it's belt slip, or a characteristic of the cams? Comp XE-R Stage 3 degreed by me. Car pulls hard and smooth on the top end. Logs overall look great.

Thoughts?

 

[01yellercobra]

I'd say you have belt slip. Especially if you have a 5-6psi drop. Have you checked around the blower pulley for dust? It might be on the bottom of the hood too.

 

[03cobra#2]

I'd say you have belt slip. Especially if you have a 5-6psi drop. Have you checked around the blower pulley for dust? It might be on the bottom of the hood too.

Yes, there is dust around the pulley for sure.

 

[01yellercobra]

Yep, you have slip. Are you on the stock tensioner? If so where does it sit on the marking?

 

[03cobra#2]

Yep, you have slip. Are you on the stock tensioner? If so where does it sit on the marking?

So I Probably need a shorter belt. It's like 1-4" from fully released lol.

 

[03cobra#2]

Yep, you have slip. Are you on the stock tensioner? If so where does it sit on the marking?

I am on the stock tensioner with a Metco brace.

 

[01yellercobra]

That's actually where you want it to be. But since you're running more boost you might need to tighten it up a little. I'm not a fan of running overly tight belts as that kills bearings. How old is the tensioner?

 

[03cobra#2]

That's actually where you want it to be. But since you're running more boost you might need to tighten it up a little. I'm not a fan of running overly tight belts as that kills bearings. How old is the tensioner?

Stock original. Car has 26k on it. Previous combo I ran a really tight belt. Maybe time or a new one. I have a slightly smaller belt I'll try first.

 

[01yellercobra]

I'm running the Roush tensioner on my set up. But I'm not making near the boost you are.

 

[03' White Snake]

I'm running the Roush tensioner on my set up. But I'm not making near the boost you are.

Same, I run 26 psi without belt slip and Roush tensioner.

 

[03terminatorcobra]

i am another using the roush. get the roush tensioner and be done. you will have to space it with some washers but that is very easy.

my old setup had the exact symptoms you were having.

 

[03cobra#2]

I have a belt that is about 7/8" shorter so I'm going to throw that on and see what it does. If not, I'll get the tensioner.

 

[Murderedsvt]

How much spacing is needed? Looking to get a roush tensioner

 

[01yellercobra]

How much spacing is needed? Looking to get a roush tensioner

A couple millimeters IIRC. I have two or three washers in there.

 

[2003RedfireVert]

Turbo LS.

 

[03' White Snake]

How much spacing is needed? Looking to get a roush tensioner

I did 3 M8 washers, I believe it added up to 3mm total. You need to shim it and swap your stock 8 rib pulley onto it. Springs are much stronger than stock and 1/5 the price of the billet ones. Highly recommend it.

 

[03' White Snake]

Turbo LS.

Why, he doesn’t want it to be slow hahaha.

 

[01yellercobra]

Turbo LS.

Just when I'm starting to like you.....

 

[2003RedfireVert]

Just smokin and jokin folks…

 

[2003RedfireVert]

I did 3 M8 washers, I believe it added up to 3mm total. You need to shim it and swap your stock 8 rib pulley onto it. Springs are much stronger than stock and 1/5 the price of the billet ones. Highly recommend it.

This will be on the winter list…