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Old 10-13-2011, 07:41 PM   #287
82mm 4g63
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I guess I've lost track of the point you're trying to make. My point is superchargers, at full boost, can lose 1/3 of their power output passively. Are you trying to say that a turbocharger will lose equal power, because of the added back pressure?

The most efficient supercharger is a centrifugal s/c, which (as you know) is the compression half of a turbocharger strapped to a crank driven pulley. It is identically as adiabeticly efficient as a turbocharger at providing power, typically between 70-80% efficiency. Roots blowers are much lower, in the 40% ballpark.

If that was all there was to compare, everything would be equal, but it isn't. Yes, a 30% loss in efficiency from a turbine is substancial, but you're not taking 30% from the final power output of the engine like you are with a supercharger. You're taking that loss from the amount of energy used to spin the little turbine.

Superchargers waste 30% of the engines total horsepower output to spin the compressor wheel.
Turbochargers waste 30% of engines exhaust gases to spin the compressor wheel.
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