It’s an expensive sport at the top fuel levels. 
.About the only racing that is cheap is foot racing, and even that gets surprisingly expensive when you start traveling and staying in hotels in order to compete.
Plus, the hotels are likely all booked up for The Boston Marathon and similar events.
I used to race small sailboats and the travel and lodging is what costed.
I wonder, is nitro-methane the only room temperature liquid with that much energy density, joules/kg? Or are there quite a few others with even higher energy density, like nitroglycerine or tri-nitro-toluene maybe, but those are either too expensive to too unstable?
Nitromethane has an energy density of about 5000 BTU/pound. Much, much lower than gasoline at about 18500 BTU/pound.
It can make a lot of power but massive quantities are burned during the process. An engine burning 1 lb per hour using gasoline will make a lot more power than an engine that burns 1 lb per hour using nitromethane.
Nitromethane releases a lot of energy per pound of AIR consumed by the engine. But it burns so rich that there is a genuine danger of hydraulic lock in an engine.
Nitroglycerin, nitrocellulose, and other high explosives need no air whatsoever.
Ok, thanks, I think I see what you mean. For high horse power output from the engine, it’s the amount of energy per second that’s important, not the energy per pound of fuel. And nitro-methane produces more energy per second than gasoline when run through an internal combustion engine.