How can I determine what rpm's my whipple is spinning?? Max constant rpm's for it are 13000. I'm running a 3.5 inch pulley on it now.

 

I have always did it like this-somebody correct me if I am wrong......Divide your lower pulley by the upper then multiply that times max rpm you are gonna turn. I think the lower pulley is 7.5 so divide that by your 3.5= 2.14 times say 6000 rpm = 12,840 blower rpm.

With that being said, I am running a 2.75 on my Whipple and shifting at 6200 rpm. That figures up to 16,900 blower speed. No problems yet and I have been running it that way almost a year.

 

The way L-Eater does it is how I figure it too.

My truck has a 7.5" crank pulley and a 2.5" Whipple pulley. It's a factor of exactly 3 times.

I'm shifting at about 5100RPM, that's a blower input speed of 15,300RPM. That's wll over the 13K constant limit and I have absolutely ZERO problems with the compressor. Last week I hit 50K miles on the supercharger to. The unit on mine is the tiny 1.6L one, not the 2.3L like you guys have. They have the same RPM specs.

What's really mind-boggling with these things is that the second rotor is overdriven by the first one 3 to 5. On my setup that second rotor reaches 25,500! It's a wonder the oil doesn't turn to froth. Just think about how far parts would fly should it ever come undone. lol

 

What PSI are you seeing with that pulley?

As far as Ranwalk's question, what L and James said is how I have learned to measure it as well. Although I believe that the max sustained RPMs are 14500. How long the Whipple could last at 13k or 14.5k RPMs is the real question since we only see max RPM at the shift points for relatively short durations of time.

 

Were did you guys get that small of a pully at. I thought 3.5 was as small as whipple made.

 

Crank X RPM / blower pulley diam.

 

I've heard people say our stock pulley is 7.5 and other say 7.75. I measured mine while it was off yesterday. I think it is 7 5/8" in diameter - more than 7.5 but less than 7.75.

 

They make pullies down to 2", of course the problem is that the belt would have very little to grip on at that size. Also, the larger the compressor the larger the smallest pulley practical is.

There are two versions of the Gen-III motor Whipple it. The dual-belt kit will accept the small pullies. The single belt kit is limited by the fact that the pulley has to fit over the drive hub on the supercharger. That hub is over 3" in diameter.

Anybody who sells Whipple can get Whipple pullies.