What pulley sizes are you running on your F1? Or I guess I should say what pulley sizes should I use with the 12 rib pulleys to make 14-18 lbs/boost?

 

Well, there is a big difference between 14 and 18psi! Mine is 17-18psi and I don't recall the exact pulley sizes and they are not where I can easily measure them at this moment, but it is pullied to max out the blower at 6,500rpm. So, whatever the exact sizes are, the ratio is ~1.5:1. There are only a few different size 12-rib belts available, I'd recommend calling Prochrager and asking them what pulley/belt combos are available to spin the blower to the desired rpm.

Rich

 

F-1 70,000rpm max
5:1 internal ratio
7.65" lower pulley
peak rpm 6500

blower pulley = 3.55"

Rich, could you confirm, (this would be a 2.15:1 ratio) you should be seeing a lot more boost with those pulleys. I would guess a 3.55" would give closer to 20# on your car.

 

Lonnie: math isn't my strong point! However, I do see ~22psi with a "bare" air inlet. Even though I had my buddy fabricate a rigid inlet pipe, I still lose 4-5psi with it. Using the POS inlet Procharger provided, it wouldn't make more than 15psi, barely more than the S-trim. As far as the math goes, I was using 50,000rpm. I guess I had a brain fart deja vu back to S-trim days. My huge dyno numbers were with the MAF removed and no inlet. If I were seriously racing the car, I would remove the MAF permanently and do something else with the inlet.

This proves two things: I suck at math and the centrifugal SC do NOT like inlet restrictions.

Rich