Tension - too little, too much?

[rossrt22]

Just found this site and I'm hoping some one can help me.

I have a Dakota with an S-Trim. I was running a 3.xx pulley, making roughly 5lbs of boost at about 5200 RPM. I go to a 2.85 pulley and make about 2 more lbs. I drop to a 2.80 pulley (I'm looking about 8 lbs through an intercooler) and I'm now seeing about 5lbs :(
My guess is not enough tension I go from a 113.5 inch belt to a 113 inch belt, it's so tight we have to roll it on. Not much help, as far a boost is concerned, still only about 5lbs.

What am I doing wrong? How much tension is too much and how much is too little. Unfortunately the tensioner on my truck has quite a bit of travel so I can't tell what too little or too much. What is best for the Vortech superchargers?

[regattacoupe]

so did you lose 2psi before or after the intercooler install? do you have any detailed pics of what you have?

[rossrt22]

so did you lose 2psi before or after the intercooler install? do you have any detailed pics of what you have?

Took the intercooler off to eliminate any possible issues with that. Actually, it didn't make any noticable difference with it on or off, but it's off until I get all my issues worked out. If I see about 9lbs of boost with the setup, I'm sure I'll see at least 8lbs with the IC. That's my goal.

What type of pics? Belt routing?

[regattacoupe]

yeah belt routing

[rossrt22]

yeah belt routing

I just posted the belt route on the photo gallery. As you can see it's a pretty long belt 113 inch , plenty of twists and turns and not very good SC pulley wrap IMHO. Any thoughts on how much tension is good enough?

[Doug]

Does your belt get its tension from the spring tensioner? If it does, I would figure out a way to make a manual tensioner, the spring may give up under boost.

[rossrt22]

Yes, the only tension is coming from the spring tensioner. I'm thinking of getting a machine shop to make a manual tensioner (move the Vortech idler pulley up and down), however is there a point where too much tension may damage the Vortech?

[Doug]

Way back when, when I had a vortech on my mustang, I use to put a bar under the tensioner with the other end on my floor jack, I would jack up the jack until the front tires were almost off the ground. So to answer your question...you are not going to hurt the vortech.

Doug

[regattacoupe]

i bet your problem is from belt slip as doug has laid out. a manual tensioner would cure this.

[rossrt22]

Thanks gentlemen.
I'll get to work on a plan for a manual tentioner. I'm also going to get a new spring tensioner, just in case the spring has lost some pull, I've got 40K on it.

[regattacoupe]

Even if it was new i doubt it would give a 6rib belt enough tension for the S-Trim. Probably takes more to turn it then all your other stuff combined. ( at higher rpm)

welcome to the site.

[V2-SQ Jess]

i see 14psi from a 6 rib. would really like an 8 rib though.