Quick question; I'm sure this has been answered but didn't turn it up...

I have been running the GReddy airpump elimination pulleys, no problem.

Now I have a new Unorthodox main pulley and it doesn't look like it is going to work with the GReddy pulleys to effectively turn the water pump.

What have others done? I'm interested in combinations of pulleys that others have used, and ideally a belt reference that works with that combination! Too much to hope for?

Thanks

 

Kent,

I'm running the Pettit main pulley with an airpump removal kit. I have good contact with the waterpump pulley and using a 28.5" belt.

 

It sounds like the Pettit main pulley must be larger than the UR pulley, since my string measurement for a replacement belt is around 26.5" - 27".

Hopefully that difference in main pulley size won't be enough to keep mine from working, too... I'll give it a try.

Fortunately these main pulleys are easy enough to swap now, I can always put stock back in if wp is slipping...

 

Did you have the alternator at it's highest or lowest point? That will also effect your distance as you measure.

I would still bet though that the Pettit is slightly larger.

 

I used to run the Unorthodox main pulley with SR alternator and water pump pulleys (both of which are bigger than stock -- are the GReddy pulleys bigger than stock?). I had some belt contact with the water pump and it worked fine for many miles, but I was never all that happy with the amount of contact. The anodize was rubbed off the water pump pulley, presumably from the belt slipping sometimes. I have since switched back to the stock main pulley to make more contact and increase the pump speed for running Evans NPG+ coolant.

Another option you might consider is an idler pulley in place of the air pump. I think Pineapple is selling one now. That would be a good way to ensure a lot of belt contact on the water pump.

-Max

 

I've run the Pettit main pulley with the E-bay waterpump and alternator pulleys with no problems. I do have a larger radiator and use NPG+ and my coolant temps are right where they should be. Unorthodox Racing sais their main pulley (Ultra S) is underdriven no more than 20% and Pettit and most aftermarket pulleys are underdriven 25%. A smaller diameter main pulley equals more underdriving so the UR pulley should be bigger diameter. UR also has an Air Pump Elimination/Idler Kit for $223.28. I didn't find PineappleRacings Air Pump Elimination/Idler Kit on their site any more.

http://www.unorthodoxracing.com
http://www.pettitracing.com
http://www.pineappleracing.com

 

I made an idler that replaces the air pump and all is well .It is adjustable like the airpump . The crank pulley is from U R the water pump pulley is as big as will fit , made here as well as all the other pulleys . I am now installing a GM alt with a very small pulley to get a high amp output at idle .That pulley will be made here as well .