DonRoc

i miss wrote it is a 8.5 crank pulley I have along with the 7.75
The 8.5 is the largest Procharger makes now

GPM

Yes

DonRoc

They told me the 7.75 and 5.5 should be around 10psi. I wanted more so ordered the 8.5 and 6 which are about the same ratio as the 7.75 and 5.5, for a start them have the 5.5 to boost it some more. I didnt want to have to change the crank pulley to get more. I felt I would get 15psi with the 8.5 and 5.5.... should be interesting. If I get 15psi with the 8.5 and 6, the 8.5 and 5.5 might be a bit much. I cant wait to see.
Ill keep you posted. Might have to put the 7.75 back on. Thanks for the information.

DonRoc

What did you use for fuel @ 15psi?

GPM

On the dyno, 94 Sunoco plus booster worked for a 7 second pull, on the water I had to go to racing gas.

DonRoc

Did you run race fuel all the time or swap out pulleys and lower the boost? I think I will shoot for a safe boost for pump gas and when I need to run it hard swap pulleys and fill it with 110.

GPM

I have 2 tanks with an electric transfer switch, pump gas and racing. Keep it at 10 and under on pump, flip the switch and go.

GPM

I would install the crank pulley and make my changes at the compressor. You might want to put a couple of dowel pins between the crank pulley and dampner.

DonRoc

I hear you thats my plan. I dont even know why they packaged it with the 7.75 and 5.5 and then said they would not reccomend going to the 5.25 due to belt slip. Hence me getting the 8.5 crank pulley...

GPM

I was wrong about my pulleys, I went and measured them, crank pulley is 7. compressor is 5.5. They are the ones that gave me 15 lb at 6300. The boost will keep increasing with RPM.