More boost???

[jfsmiata]

Hi everybody, I'm new to supercharging, looking for a little help.
I have an '01 Miata, BRP MP62 hotside, 9 psi boost, TD a/a IC, RC 550 cc fifth injector with a BRP controller, JR boost/timing controller, eng is stock, stock ecu, 70 mm BBK tb, stock inj's and fp, using 91 octane, JR header and 2 and 1/2" exh, pulleys are 130/67.5 and are 4 rib, currently at wot I'm getting
11:1 to 12:1 afr. I'm hoping I can just change pulleys to run at 12 psi without any further changes, what do you think?

Thanks, Jamie

[Tom @ Fast Forward]

Hi Jamie. From our conversation this morning, my concern with a smaller SC pulley is possible belt slip and possibly insufficient fuel.