I've been searching and couldn't find good complete info so I thought I'd post this based on my scale (not caliper) derived measurements.

Comptech SC Pulley Dia: 138mm (5.43")
Novi 1000 Internal Ration: 3.54
AP1 Rev Limit Set Point: 9,200rpm
N1000 max Impeller Speed: 55,300

I checked the 3.0 Pulley, the 3.4 Pulley, 3.8" Pulley, and 4.2" Pulley, the dimensions hold true.


4.2" Pulley 42,130 rpm
4.0" Pulley 44,236 rpm
3.8" Pulley 46,564 rpm
3.6" Pulley 49,151 rpm
3.4" Pulley 52,042 rpm
3.2" Pulley 55,295 rpm
3.0" Pulley 59,925 rpm

Let me know if anyone has different info of if you can support the analysis. Calculations courtesy of excel.

By this, the 3.0 Pulley is overspinning the blower by 8% and much of the added ~1psi is probably from outlet temperature increase. However, the 3.2" pulley sees to be right at home in the AP1; perhaps SOS doesn't recommmend it for AP1 for the same reason? I'll recheck the diameters with more accuracy when I finally get around to ordering a 0-12" caliper with big enough jaws.

Finally, the 3.0" Pulley seems to drop out of overspinning when the rev limit is set at 8,500rpm.

 

After doing some playing around with the values, I don't think using a scale was a superb choice but the results appear to be good rough numbers.

 

That is consistent with what I understood before running a 3.0 pulley.

 

Whats with the 9200rpm rev limit? Are your calculations based off of this? 8900rpm is factory if we are going for max oem rev with blower speed.

Thanks for the thread

 

Good info.

I'd like to do the same calculations for the 2.2L engine.

 

There are a lot of people who believe the fuel cut to be 9200rpm or so, but this is only because of the tach reading a little generous near redline. Calculations really should be done at 8900rpm as you are saying, this is what the ECU is really cutting fuel at and you can see if you're using any sort of logging equipment