Depending on the racing club, we have restrictions on coolants as well. My club allows Propylene Glycol but not Ethylene Glycol. If your club(s) exclude anything but water, you are back to pump efficiency and cavitation issues. Hp draw due to the pump is minor especially if the pump keeps...
Our roadracers cooling problems went away when we switched to Evans Coolant. Without water, cavitation is seriously limited at any RPM. Running the pump faster will then lower coolant temps.
Maybe brake fluid goes bad too quick. I know any old bike I work on usually has black goo for brake fluid. A better answer might be price and what it does to paint when spilled.
How about 100% propylene glycol or a propylene glycol/ethylene glycol mix as a coolant. The heat transfer isn't as good, but the boiling point is way up. Racers are using it as an alternative to water and water wetter. I heard of a Corvette team using water and (I think) a 90 psi radiator cap!
