[hotrod]

Well the answer to your question depends on what your goal is.

If you trying to control mixture temps, post blower might work slightly better than pre-blower but I doubt the difference would be much.

If your trying to increase the total air flow to the engine without going to an higher overdrive ratio -- the only way to do that is pre-blower injection.

A blower (roots/eaton type) is a positive displacement pump. For each revolution it will move x amount of air. The only way to increase that flow is to spin the blower faster or increase the air density at the inlet. If you cool the inlet air temp the blower will actually act like a slightly larger blower, for each revolution it will move x+y air. The Y depending on how much cooler the intake charge is. If you want to get technical there is also a -z term for the air that leaks back through the blower seals, and pre-blower injection reduces that loss due to leakage.

If you are running the blower at a given rpm, no matter how much post blower cooling takes place, you will still flow only the air the pump can move each revolution. At some point extra cooling post blower only serves to increase charge density by cooling but also drops the boost pressure because its dealing with a fixed flow, based on the rpm of the blower rotors.

IF your detonation limited, cool after the blower, if your flow limited, cool/spray ahead of the blower (or both).

Larry