For enquiring minds. The equation below will calculate pulley ratio for roots type blowers.
(14.7 + boost / 14.7) x (engine volume/2) / supercharger volume =pulley ratio

So if I want 8psi of boost.......

14.7+8/14.7 x 3.2/2 / 1.5 liters for my M90
1.54 x 1.6 / 1.5 = 1.642:1
So i need a pulley that will turn 1.642 times for every 1 crankshaft turn
Keep in mind that this is assuming that the supercharger is going to work at 100% efficiency, which in reality it is about 80% efficient. I should get about 6.4 psi of boost which should be safe and near the superchargers lowest output temperature. This should also equate to about 1.43x more power. 215x1.43=307.45HP 230x1.43=329 TQ
These are rough estimates but should be feasible.

After I remove that huge intake there is tons of room for the Supercharger!