Blower H/P question
 

Heard A while a go that it takes a certain amount of horse power to generate boost. Is there a simple formula?

I have done some reading on supercharging and there is no simple formula. It will depend on the type of blower (roots, screw, centrifugal,...). Also, when you are talking blower 'efficiency' there are three main types of measurements and the combination of all of these have an impact on overall performance.

Adiabatic Efficiency - How much it heats the air when pumping. Heating the air reduces horsepower.

Mechanical Efficiency - The amount of engine horsepower the blower actually consumes to produce a certain amount of boost at a given speed, compared to the theoretical amount of power needed.

Volumetric Efficiency - The ratio of actual volume of air it pumps per revolution compared to its internal displacement per revolution.

Interesting stuff... From what I understand the screw type supercharger is probably the most 'efficient' over the widest rpm range. Hope this helps!:drink:

I don't think the term how much H/P to make boost is right at all, blowers will required a certain amount of H/P to turn them, then the size of the blower, size of the engine, camshaft, heads, and blower drive ratio will determine boost...Rob