Quote Originally Posted by UselessPickles View Post
I don't think anyone ever claimed that the turbo would produce more boost than the superchargers, but only that the turbo would produce more power. A turbo produces power more efficiently than a supercharger because it is using heat energy from the exhaust that would be otherwise thrown away out the tail pipe. The superchargers get their power directly from the crankshaft, so there is more parasitic power loss. Given a turbo and a supercharger that produce the same peak boost, the turbo will produce more net power to the drivetrain.

For the RIPP (and other centrifugal superchargers) specifically, even with the 11 psi high altitude pulley, you only get that 11 psi at 6500 rpm (and only if running down near sea level). The chart I posted with the RIPP boost curve appears to be with the high altitude pulley, because it gets up to just over 10 psi. Compare that boost curve to my boost curve. If the additional boost of the high altitude pulley being run at low elevations is enough to catch up with or surpass the power of the turbo, it will only beat the turbo near redline.

Somewhat unrelated, but speaking of high altitude pulleys...

The intent of the high altitude pulley is to compensate for thinner air at higher elevations, and produce the same amount of boost up there as the normal pulley would produce near sea level. With a given pulley, a supercharger will lose boost as go up into higher elevations.

The turbo, however, adjusts to changing elevations automatically. Its boost is controlled by a wastegate, which is calibrated to open up when boost pressure exceeds a fixed amount of pressure above ambient pressure. My turbo will produce about 8.2 psi peak boost at sea level, and up in the mountains, without making any adjustments.
Thanks Pickles, food for thought when making a decision between the two.