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pulley's and blowers

10 November 2003
I just changed my blower pulley from the comptech 3-5/8" to a custom made 3" now I need to find other ways to reduce belt slippage. At first i went from 7to 8 PSI to about 4 PSI than i started to tighten up the belt and got it up to 10 PSI. can i over tighen the belt? I currently do not have as much belt wrap as the comptech due to my intercooler. would this make that much of a diffrence? My blower is a 813CFM per rev unit or a 2.3L my goal is about 15 to 16 PSI. I was thinking of building a custom pulley plate that will run everything but the blower and then running a COG style just to the blower from the crank. I guess the biggest down side to supercharging is the oil system being in the way limiting the size of the lower pulley. Has anyone changed out this set up giving more room for the pulley's?
You need more belt wrap or a wider belt. I would shy away from the more tension idea. Is there a way to mount a tensioner strategically to obtain more wrap? :smile:
The tension you can apply is limited by the weakest bearing, which in this case is the alternator. A secondary drive would be the only way around the tension issue, but space will probabally be a problem. If I were you, I would find a local CNC shop and have all three pulleys modified for cog use.

On a differant note, be sure and mind the maximum blower rpm when deciding how much boost you can make. Divide the drive by the driven and multipy by 8200 (for safety) for max blower shaft speed. In the case of a centrifugal, you then have to multiply shaft speed by gearbox ratio to determine max impeller speed.