How much energy or power to spool a turbo?
 

As title says, we were talking about this at work today...



Obviously a turbo’s turbine is spooled by energy (heat, flow, whatever) wasted out the exhaust of the engine, but how much energy is that?



Someone here said it was meant to be the equivalent of 1bhp for a T25 pushing 0.5bar boost or something along those lines, but surely its far more?



(just to clarify, I dont mean its power sapping effect on the engine due to backpressure or increased charge temps, i mean purely what energy is needed to spool the turbo)



I guess in some lab somewhere this has been tested, so, has anyone got any idea what the reality of it actually is?

Well, a td04h 15g flows ~400cfm, and a 22cc engine moves 400cc of air, sooo.... 2-5hp, so your 1bhp for 7psi ona t25 sounds about right. Though I have seen a weak 200cfm leaf blower gain 50hp with no tuning or IC lol.



But you would think a SC would be much less power sapping if that was true..... So I am not sure. lol