I like the supercharger driven by the starter motors. With three of them, you get the torque. Using a bank of batteries removes the instant drain on the charging system, only to charge them back up later. My only worry would be the motors. No two motors are exactly alike and it would be impossible to synch them. I would assume the weakest one would be over driven by the other two until they started to fatigue. It would got in a circle until they were all toast. Some longevity data would be nice, but I also agree that it probably does not matter.

Now, that SC would work. Again, no leaf blower here, and actual and true compressor.

It might even be possible to go with a blower that would not usually be used. Since driveability or low RPM use would be a factor (again, I am assuming there is some sort of bypass for the unit when not in use), I bet you could get away with something that would move a volume of air that would be more condusive to high RPMs.

But, then, that is a the kicker. A belt driven blower blows in response to engine RPM. The above blower would have one CFM and one PSI to operate at. It would have to be tuned for a specific RPM and only used there. Kind of like NOS and WOT.

Michael