Belt size for underdrive crank pulley?
 

I picked up a used underdrive crank (eccentric shaft) pulley. Does it require a special belt, or can I use the factory size? It's alot smaller than stock, so i'm assuming i need a different belt than stock. If so where can i find it, or do you have the # on the belt. thanks

Take some string or twine, run it around the path the belt will go. Then measure the distance of the string and you'll have the size you need.

I always just go here

http://www.pettitracing.com/rx7/index_performance.htm

and use the part numbers off the belts

Keep in mind, that those are designed for the size of Pettit's main pulley and most likely the stock alternator pulley. If either of those two are different, the belt size may or may not fit.

It show the belt sizes for applications which only have the underdrive main pulley. It worked for the underdrive pulley i have but i have no idea who made it. I just figured the size would not be out of the realm of adjustment.

I know for mine which was an RE underdrive main pulley the belt for the PS and A/C was a 6 rib 40". I would have to double check the wp and alternator pulley belt.

The one i have does look like pettit, but it looks like it has been powdercoated silver, same hole pattern as pettit or rx7.com pulley.Is the belt i need is the 5 rib right. Pettit 5pk1295. This is for the crank,powersteering,ac ?

try banzaii racing thats where i got mine from.

Quick question, is the pettit power pulley kit really worth the price?

I mean 250$ for 2 belts and 1 pulley seems a lot to me but I'm just asking. Does it really help increase performance..?

Since we're talking about belts here, I removed my AC which requires me to use a smaller belt, but I still have PS, and I have the GReddy alternator pulley, and water pump. I was lookin on Banzai racing. Does this sound like the right belt?

Belt #3: Stock Main Pulley, Underdrive Waterpump* & Underdrive Alternator* (No Smog Pump)

780mm x 5-Rib

NOTE: fits GReddy Pulley Kit for Smog Elimination, Indigo Pulleys, EBay Pulleys, etc.

Thanks, i'm gonna go with banzai

You would need a #3 for the WP/alt and #5 for the PS