Jacob, you're talking pigeon poop.

You cannot ADD horsepower to an engine by adding water to the fuel stream.

What water injection does is to alter the flame front in the cylinder (or in a turbine) to changhe the temperature and speed of the burn and it adds more mass to the combustion mixture to make it a more efficient medium for transmitting the energy to the piston or turbine blade.

Basically, if you take a 1000 HP aero engine and bring it to such a high state of tune that it is theoretically capable of delivering 1300 HP, it is so unstable and kermudgeonly that it won't run right. It pre-detonates at high compression ratio and has problems starting.

If you add water injection to the package, it stabilises the flame and slows it down so avoiding pre-detonation and aiding the starting mixture.

You aren't adding energy from the water, you're doing that by adding more fuel.

If you look at the performance and fuel consumption figures for those aricraft, they werenb't getting a "free" boost - they were burning fuel in bucket-loads to do it and the water injection stopped the engines exploding when they did so.

Water injecvtion into gas turbines can control NOx emission by altering flame temperature and gives more stable running at high loads BUT COSTS MORE TO RUN because you have to pump the water in at high pressure, so they only do this at my local gas-turbine power station when they have to to meet emission standards, otherwise it costs money.

Don't you think that if one could inject water into an engine and get a power boost, that some enterprising engineer wouldn't have done it on a hot rod by now, at the very least, let alone a production car?

Oh, I forgot. There's a "conspiracy" by the "seven sisters" to keep this technology from the public.