2.9 L whipple supercharger belt size

[BeckSVT]

I have a 2003 cobra that I bought a gen 4 2.9l whipple and was wondering what size belt I am gonna need.
Upper Pulley: 3.5"
idlers: all stock 90mm
added snub idler to help with belt slip: 100mm
stock lower pulley.
Please let me know thanks in advanced.

 

[olympic]

03-04 Cobra Supercharger Belt Chart - LMR.com

The chart is geared towards the stock eaton s/c but it says to add 1" for the idler and another 0.5" for a 100mm idler, so 1.5" total. 75.5+1.5= 77". You can confirm this by wrapping a string (or an old belt) around the pullies and then measuring it's length. It's a 2 person job though since you have to hold the tensioner in it's operating position while measuring.

 

[BeckSVT]

But doesn't the pulley on a Whipple sit higher then an Eaton?

 

[01yellercobra]

I'm running a 76.7" I think. The next step was 77.1". Its on the snug side for me. But I have 2 100mm idlers, 90mm idler, whipple aux pulley, and a J2 Fab alternator. I know the alternator has a slightly bigger pulley as I had to move the aux idler. When the time comes for a new belt I'm going with the 77".

 

[MG0h3]

I’ll look when I get home but it’s a gates ends in 080. Whatever the first digits are.

It’s a touch under 80”.

Edit: think it’s 080780. I’ll check when I get home.


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[BeckSVT]

Ok cool let me know for sure

 

[MG0h3]

Ok cool let me know for sure

I have an both an 080780 and an 080765 hanging on my cherry picker. When I bought the car it had a 3.75 upper. When I moved up to 4k’ I dropped to a 3.5 upper.

Not sure if the 765 belt was run on the 3.5 upper or if that was a trail fit when I pulled down for E85.

I’d get the 080 and 765 and then return whichever you don’t need.

My gut tells me I ran the 080 on both the 3.5 and 3.75.

I’m on a 760 belt with the 2.9 upper pulley.


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[BlckBox04]

the last three numbers are the length of the belt

 

[MG0h3]

the last three numbers are the length of the belt

Close anyways. Gates rounds them but I’ve found them up to 1/2” different bases on specs from their site.


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[BlckBox04]

Close anyways. Gates rounds them but I’ve found them up to 1/2” different bases on specs from their site.


Sent from my iPhone using the svtperformance.com mobile app

was it a regular or HD?

 

[1Bad04Mystic]

03-04 Cobra Supercharger Belt Chart - LMR.com

The chart is geared towards the stock eaton s/c but it says to add 1" for the idler and another 0.5" for a 100mm idler, so 1.5" total. 75.5+1.5= 77". You can confirm this by wrapping a string (or an old belt) around the pullies and then measuring it's length. It's a 2 person job though since you have to hold the tensioner in it's operating position while measuring.

What did you end up going with? Just ordered my 2.9 Whipple Gen 4, and I have your exact same setup.

 

[olympic]

Deleted.

 

[olympic]

What did you end up going with? Just ordered my 2.9 Whipple Gen 4, and I have your exact same setup.

My pullies consist of:

Stock diameter Metco lower.
3.25" Whipple upper.
3x100mm Metco idlers
90mm Metco snub idler.
Thump Racing tensioner.
Mechman alternator with 2.5" pully.

Currently running a Gates RPM 78" belt part# K080780RPM.