"...Swamp Cooler Theory 101:..."
"...unfortunately, THAT's gonna take a LOT of water, especially if you're driving at freeway speeds (higher RPMs) for any appreciable time...literally, gallons-per-hour! ..."
what if you captured the H2O to re use it? Maybe a radiator in the bottom of a stainless steel box. Water vapor condenses on the walls and drips down to the radiator. Seems like trying to take advantage of the phase change from liguid to gas could yield some really impressive results. Some of you engineering/scientist types may be able to explain what I'm thinking of (or why it wouldn't work).