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      04-12-2011, 10:32 AM   #32
scheherazade
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Drives: 09 GTR (& 93' accord!)
Join Date: Sep 2008
Location: DC metro area

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Quote:
Originally Posted by Onurleft View Post
Superchargers turn off the crankshaft, the faster the crank spins the faster the supercharger turns. Hence the more RPM you turn the more power you will make until the system becomes inefficient (heat soak etc.). You got that backwards
not quite.

small turbos will spool fast, but can't move as much air at their peak rpm - sometimes less than the engine requires to maintain a target manifold pressure (boost drops off to redline).

Superchargers increase RPM in proportion to engine RPM.
That's also what limits their peak output.
http://www.dragtimes.com/images_dyno...e-ZR1-Dyno.jpg

A turbo can increase RPM well in excess of the increase in engine RPM. (i.e. engine rpm doubles, turbo rpm more than doubles, etc)
You'll find that 'silly power' (street) applications are as good as always big turbos (They aren't limited by engine rpm).
http://www.proefi.com/uploads/dynograph_supra_large.jpg
http://i56.photobucket.com/albums/g1.../supradyno.jpg

(caveat for things like top fuel dragsters : no exhaust system to drive a turbo, can't afford any lag)

-scheherazade

Last edited by scheherazade; 04-12-2011 at 12:44 PM.
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