http://youtu.be/48EWfS800Xs


I hit peak boost in 3rd at 10.5lbs, 1st and 2nd don't seem to hit peak boost. Reasons? Normal?

 

Build list would help alot.

Also "usually" you will not hit full boost in 1st and 2nd and some builds in 3rd. Traction plays a big factor here.

 

not enough load?

 

^ That too

 

i was going to say load on the engine but with him asking about belt slip i think this is a supercharged vehicle.

with a s/c load doesn't matter so it would have to be a leak or belt slip BUT if it leaks or slips in 1st it will probably do it in all gears.

 

When you are in 1st or second the revs pickup more quickly and the belt can't keep up and the belt slips. In 3rd it has more traction because the engine's revs pick up slower. You most likely have a belt slip issue. Do you have the GTM pulley upgrade?

 

Im running a vortech v2 supercharger. Think its the 3.33 pulley

I might need to tighten the belt up because it is a new belt.

 

wouldn't the higher load affect belt slip in the higher gears?

when i had belt slip on the old vortech it was all across the board.

that being said, it's a new belt and generally people never tighten the belt tighten enough. Vortech belts have to be crazy tight.

 

I'm surprised he is hitting 10.5psi with the 3.33. I don't think the load on the engine would cause more load on the belt but I'm not an expert. The supercharger has a lot of drag and my guess is when the engine revs quickly in first or even second gear the quick reving makes the belt slip while it's trying to speed up the supercharger accordingly.

 

ya, 10psi is crazy for that. Something doesn't seem right.

I agree with your thoughts on the revs. With the higher rpm and boost the vortech would have way more resistance therefore the belt would slip as it tries to turn the vortech faster and faster. That's why i think it slips with higher load too.

 

The 3.33 pulley is rated for 8-10 psi and I was tuned for peaking at 10psi. I dynoed at 373 rwhp.


Im going to get the belt tightened wednesday to see if that helps, Im almost positive that is the issue since traction becomes a problem in 1st and 2nd. I hit peak in 3rd so im sure it s a belt slip and no a leak.

 

i'm going to assume you have a rev-up engine because non-rev engines it's 6-8psi for 3.33, 8-10 for 3.12 and 10-12 for 2.87.

it would be slightly higher for the rev-up though so if you have a rev up then 10psi is probably correct.

 

Thought the revup used the 3.12 stock? They also have different teeth counts on the jackshaft and blower?

I have been out of the vortech loop for a while so im not 100%.

 

they might. i've never owned one so idk. I guess someone could always go down to a 3.33 pulley

 

Affirmative, ghostrider...

And revup cogs are 34 (jackshaft)/32 (blower)

 

I tightened the belt and no slip. Im almost hitting 12 lbs now lol, maybe I tightened it to much.

 

no such thing as too tight unless it breaks.

boost won't change due to tight or loose belt. Once you have zero slip the boost will always be the same. You want zero slip so i doubt you're too tight. Mine was the the point if i plucked it with my finger it sounded like a guitar string.

At the longest distance between 2 pulleys, grab the belt right in the middle of the 2 pulleys. Try to twist it over so you are looking at the ribbed side. With 2 fingers you should just barely be able to turn it 90* on it's side. if you can turn it all the way over (180*) then it's too loose. 90* is about right for tightness.