2.9 whipple pulley/Belt

[Brian Kuntzman]

Good Morning Everyone. I recently purchased a 2.9 whipple for my 03 and I am trying to figure out a belt and pulley combo for pump gas. I wanna run 18-19lbs. I am thinking a 3.275 with stock lower is this too much or will it get me where I need to be? Currently all stock pullies with a 90mm idler. Not sure if there is a belt size chart for them. Can not seem to find one

 

[willis414]

I thnk 3.50 upper with factory exhaust manifolds will put you where you want to be. Might be around 75" on the belt

 

[olympic]

I agree, stock lower and 3.5" upper should be real close to what you want. I've got a 2.9 waiting to go in as well and that's the pulley combo I'll be starting with.

 

[ShootyMCstabby]

So a gates k080774. will put you at about 80-85% on the stock tensioner.
with sock lower and a 3.5 pulley. on a 2.9/3.4

So at that tension I wouldn't try the HD (green belt) as that belt has less flex.

I moved up to a k080780rpm for the 3.5 pulley. Which is about .6 of an inch longer then the 774.(last 3#)

 

[Reload469]

So a gates k080774. will put you at about 80-85% on the stock tensioner.
with sock lower and a 3.5 pulley. on a 2.9/3.4

So at that tension I wouldn't try the HD (green belt) as that belt has less flex.

I moved up to a k080780rpm for the 3.5 pulley. Which is about .6 of an inch longer then the 774.(last 3#)

Are you running an additional idler? I'm running a 3.4L and wanted to look into an RPM. Didn't realize that they had started making an RPM that would fit the 3.5 pulley on the 3.4L. Would be awesome to put one of those on!

 

[MG0h3]

I ran the 08780 on both a 3.75 and 3.5 upper stock lower with no issues.


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[Brian Kuntzman]

Okay so it seems everyone says go with the 3.5 pulley over the slightly smaller. I do have long tubes on the car so i will drop boost some. Also have a 90 mm idler with stock pullies everywhere else