water injection is also used in tractor pulling. pro stock and super stock tractors inject massive amounts of water, compressed air, and fuel to generate upwards of 3,000 hp (pro stock) and 5,000 hp (super stock). not only does the water cool the intake charge, more importantly it prevents the block from melting! also, conversion from water to steam in the cylinders produces additional horsepower. ALOT more horsepower.
http://www.youtube.com/v/_Szp_fIWDbQ