DRIVER456

I have a stock size ATI crank balancer with a 3.5in SC pulley making around 10lbs of boost,Im going to a IW 10% OD 8.5in. crank balancer,Roughly what size SC pulley would i need to get to keep it the same boost? 4"?

silver408z

https://928motorsports.com/services/selectingpulley.php

There is a calculator to help figure out what you need.

DRIVER456

thank you, 3.90" comes the closest which that company has,thanks again

aaronc7

Are you sure the diameter is 8.5"? IW lists their 10 OD as 8.125" and 15 OD as 8.3xx". Either way 10% OD and 8.5" diameter does not compute, I would double check. I've seen A&A post a few times that general rule of thumb when you go to the IW balancer to run a s/c pulley that is 0.2" larger to compensate. 3.9 you may lose too much unless the pulley is indeed 8.5".

DRIVER456

ok yes you might be right i measured outside to outside not down in from the grooves,I'll double check everything

DRIVER456

Ok i checked there website it is 8.125.thanks aaronc7