[hawk2100n]

Originally Posted by serialk11r

I already shot my own idea down, the only energy recoverable is miniscule in most cases due to the way Roots blowers are built.

I know no work is performed on the throttle body, the point is that there is an energy loss due to free expansion at the throttle body in the typical case. Cylinders drawing air unevenly reduces this slightly. As I wrote, a Roots blower would suffer nearly the same magnitude of loss to free expansion while having additional inefficiencies, thus it's not a good idea. I was mistaken in thinking it would recover significant energy because that energy would come from the pistons pulling a deeper vacuum.

And again, if the Roots blower exit was coupled more or less directly to the intake valves then it would be a different story but that's very difficult to do.

Actually timed pulses from a roots blower is a good idea and wouldn't be too difficult. You would need a blower running at engine speed with n/2 lobes where n is the number of cylinders. And timing isn't complicated because you could put it on a toothed belt like top fuel dragsters and extremely high performance cars do. And timed pulses could keep a more even pressure inside of the manifold.

I would love to be in engine development. Maybe one day...