Power to Burn
The primary benefit of nitromethane is that much more power within a given displacement engine is available when compared to gasoline.  Nitromethane is actually less energetic than gasoline, however more power per stroke is available.

Nitromethane’s primary chemical advantage is that it carries its own oxygen atoms to burn…gasoline combined with nitrous oxide is another way to consider nitromethane.  Today’s top fuel dragsters can burn up to a gallon of nitromethane per second.  Consider that while it takes 15 pounds of air to burn a gallon of gasoline, it only takes 1.7 pounds of air to burn 1 pound of nitro.

What about those flames?
Nitromethane burns slower than gasoline.  When the spark plug fires and the exhaust valve opens, the engine is pumping still-burning nitro through the exhaust pipe…flames.