Whipple pulley sizes

[GoFaster06]

I have the 3.5" Whipple pulley for 10#'s of boost on HO kit. Want to change pulley to either a 3.25" (11-12#'s) or 3.125" (12-13#). Belt setup is unchanged from original Whipple install except I have upgraded to Thumpr tensioner. My question is can I just change to smaller pullies & use same belt or do I need to do other modifications?

 

[AbdullaGT500]

You will have belt slip with the 3.25 or the 3.125. Install a larger idler pulley on the thumpr tensioner, I believe a 90mm is what you need. I wouldn't even get into boost until doing that. Mine shredded the belt and put a nice sized outward dent in my hood and also chipped the paint.

 

[GT E UPP]

Had no problems what-so-ever with 3.25 pulley (11psi) and Steeda-Whipple 10 rib belt drive system...

 

[AbdullaGT500]

Had no problems what-so-ever with 3.25 pulley (11psi) and Steeda-Whipple 10 rib belt drive system...

That's not what the OP was asking...

 

[BruceH]

You can also change positions of the pulleys to make up for the smaller drive pulley. Whipple allows for a wide range of sizes with the sliding idler. You could probably go from 3.5 to 3.25 and just use the slider to take up the slack. The Whipple directions have a diagram of what pulleys to use when changing drive pulley size.

 

[GoFaster06]

You can also change positions of the pulleys to make up for the smaller drive pulley. Whipple allows for a wide range of sizes with the sliding idler. You could probably go from 3.5 to 3.25 and just use the slider to take up the slack. The Whipple directions have a diagram of what pulleys to use when changing drive pulley size.

I did find my Whipple directions. It looks like I would need a 100mm, correct? Where would I purchase this from? Whipple or other known companies?

Would this work: http://www.lethalperformance.com/whipple-100mm-mustang-6-rib-idler-pulley.html

 

[BruceH]

I did find my Whipple directions. It looks like I would need a 100mm, correct? Where would I purchase this from? Whipple or other known companies?

Would this work: http://www.lethalperformance.com/whipple-100mm-mustang-6-rib-idler-pulley.html

Just get one off of rockauto.com. The sizes are listed for gates smooth idlers.

 

[GoFaster06]

Just get one off of rockauto.com. The sizes are listed for gates smooth idlers.

I looked but could only find a 90mm, need 100mm. Not seeing it, am I looking in wrong spot?

 

[rayS197]

Jay, have you considered the Steeda 10 rib setup? The kit comes with an SFI balancer which is another plus. No its not cheap.

 

[GoFaster06]

Jay, have you considered the Steeda 10 rib setup? The kit comes with an SFI balancer which is another plus. No its not cheap.

Yes Ray I have, but cost has is a little too steep for me right now.

 

[AbdullaGT500]

You can also change positions of the pulleys to make up for the smaller drive pulley. Whipple allows for a wide range of sizes with the sliding idler. You could probably go from 3.5 to 3.25 and just use the slider to take up the slack. The Whipple directions have a diagram of what pulleys to use when changing drive pulley size.

Even pushed down as much as possible, I still think he may have belt slip with the 3.25.

I did find my Whipple directions. It looks like I would need a 100mm, correct? Where would I purchase this from? Whipple or other known companies?

Would this work: http://www.lethalperformance.com/whipple-100mm-mustang-6-rib-idler-pulley.html

The Whipple kit already comes with a 100 MM idler, so chances are you have already installed one in place of the stock 90 MM on the top left. Why not just put a larger idler on the tensioner?

 

[GoFaster06]

Even pushed down as much as possible, I still think he may have belt slip with the 3.25.



The Whipple kit already comes with a 100 MM idler, so chances are you have already installed one in place of the stock 90 MM on the top left. Why not just put a larger idler on the tensioner?

My kit is the 550hp HO kit 2nd generation, 3.5" pulley setup. You swap out the P/S 76mm to 90mm, D/S stays 90mm. Both upper pulley are now 90mm. Still need the 100mm as Whipple diagram in directions show.

Wouldn't I have to buy an idler either way?

 

[wht67]

My kit is the 550hp HO kit 2nd generation, 3.5" pulley setup. You swap out the P/S 76mm to 90mm, D/S stays 90mm. Both upper pulley are now 90mm. Still need the 100mm as Whipple diagram in directions show.

Wouldn't I have to buy an idler either way?

I have the 100mm pully that came with my Whipple Big Boost kit. When I irst installed the kit I had squeaking and I thought the 100mm pully that came with the kit was the culprit. I bought another 100mm pully and that didn't fix it. (ended up putting a new belt on and that fixed it). The extra 100mm pulley I have has maybe 50 miles on it. still looks new. PM if interested.

 

[GoFaster06]

I have the 100mm pully that came with my Whipple Big Boost kit. When I irst installed the kit I had squeaking and I thought the 100mm pully that came with the kit was the culprit. I bought another 100mm pully and that didn't fix it. (ended up putting a new belt on and that fixed it). The extra 100mm pulley I have has maybe 50 miles on it. still looks new. PM if interested.

What size Whipple pulley are you running & how much boost?

 

[AbdullaGT500]

My kit is the 550hp HO kit 2nd generation, 3.5" pulley setup. You swap out the P/S 76mm to 90mm, D/S stays 90mm. Both upper pulley are now 90mm. Still need the 100mm as Whipple diagram in directions show.

Wouldn't I have to buy an idler either way?

Passenger side was definitely not a 76mm on my 3V car from the factory.
Stock passenger and driver side upper idlers are 90mm. The whipple HO kits come with a 100MM idler for the passenger side. The stock tensioner has a 76mm idler, though.