F=MA
HP=(Torque x rpm)/5252
Kill Kill! (from Arlo Guthrie's Alice's Reasurant part where he is talking to the shrink)
2200 RPM has 4 puleses per revolution. 8800 pulses per minute. Well 9000 divides into 60 nicely, that would be about 150 Hz of primary exhaust puleses.
and a few other things I better not talk about