The supercharger takes power from the engine when pumping boost. When cruising the blower is spinning in a partial vacuum, so it consumes very little power. In fact I have had blower belts break, due to a backfire, and the blower just kept spinning, due to the engine pulling air through it.
The fuel consumption is the same for both, as long as they are driven the same.
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"Gains power from exhaust gas and not directly from the engine, hence the engine is gaining without a loss." Quote.
The old saying " you get nothing for nothing". The turbo does consume power from the engine. To fit the turbo, the existing exhaust system has to be removed and replaced with a short system to power the turbo. So the power that the factory exhaust provided is now lost. The low speed Inertia is not there, or the high speed resonate system is not there. So this must be considered as power taken to drive the turbo.
The other differences are the supercharger has a cooler air output than the turbo, that suffers from heat transference from the turbine side to the compressor side.
The supercharger provides boost at low rpms, but is inefficient above 1.5 atmos boost. The turbo provides little boost below 2500/3000, but can produce boosts in excess of 1.5 atmos.
Harvey.
