Variable Compression, Variable Displacement you decide

[Frederic Breitwieser]

>Again same as above.  The auto books I have read say the biggest problem
>with a supercharger is how much power the use at high rpms.  This they
>say is the only disadvantage of a supercharger over a turbo.

This has been my perceptino as well.

Turbos offer much better performance in the mid-high end of the RPM range,
simply because they have to spool up based on lower exhaust pressure at
lower RPMs.  Superchargers, being belt driven, and most of the time driven
by a 1:4 or a 1:8 gear-up system, right off idle are making boosted power.
The problem with superchargers, as you said, with a 1:8 planetary drive
(for example), your engine sitting at 6000 RPM, your blower is spinning at
6000 * 8 = 48000 RPM.

It comes down to application - for a street car with not so high RPMs (lets
say, around 5k or so), a supercharger is great.  Turbos tend to be better
for road racing and/or tracks of that sort.  Of course, there are millions
of exceptions.