[reformed]

Just a hairbrained thought.

Does anyone know how much power it takes away from your engine to drive a turbocharger? and what RPM you can start making usable power with them? I looked briefly for that but all I've come up with is efficiency numbers of the turbo itself. My idea is to use a turbo to drive the accessories via a pulley attached directly to the turbo instead of using the crank itself. You wouldn't actually use it to compress air back into the cylinders, simply to drive the accessories with exhaust gas and possibly make the engine more efficient through the elimination of the parasitic loss of the accessory belt. I say this is hairbrained because I know you have to spool up a turbo to get it to do anything, but maybe you can redesign the vanes to operate at different speeds and also not to compress the air, but rather turn a pulley... Just a thought. Opinions?

Edit: although the increased backpressure in the system, combined with the low revs that one would use in a FE driving application, may make the combustion diluted with exhaust gas, therefore lowering power output of the engine.