If the replacement is simply lighter than stock but same diameter the S/C would rev at the same rpm as the stock. A little less engine Tq loss would result..less mass to rotate.

 

It would rev at the same RPM yes but it would get to that RPM quicker (less mass inertia) meaning if there was belt splippage before, there would be more now because the rate of RPM increase (and decrease) would be quicker.

Right?

 

Less throttle to get to a comparable speed (rpm). However the mass difference is rather small relative to the total inertia of the engine+drive train that probably wouldn't sense it..

 

+1 Can we keep the other two pulleys from the UR set? (Are they even underdriven?) Also, is anyone interested in a UR Crank Pulley for sale?

 

I don't see why you can't keep the other 2 UR pulleys and get a KJR. I am not very familiar with the belt issue with SC motors. They are slipping why? Is their a new tension setting needed for the belts ?

 

John, could you offer OEM belts or point me to a place where I could get them at a good price? Cause right now I have gates (smaller diameter) belts due to running the UR 3 PC Pulley set. I'd like to run the KJR Pulley with the 2 UR (non-crank) pulleys. Or would a SC kit come with replacement belts?

 

ReavTec- I have a stock diameter aluminum crank pulley custom made from ASP. I had it made for about 165. I bought it for the procharger (when I had one). If you want I will trade you my stock sized pulley and belts for your unorthodox undersized pulley and belts. My belts only have around 2000 miles on them. Pm me if interested.

 

ktown, can I get in on this deal? How was your experience with the lighter pulley and the SC?

 

we have the lightened stock size pulley for 170 shipped at www.kjrperformance.com