Quote:You still have just as much fuel and air (practically speaking), so the answer is no. Instead, the water cools the a/f mixture, so you advance the timing. The effect is similar to intercooling, but it's done internally (it cools the mixtuer in the cylinder during combustion).

There have a been a few factory turbo cars that used water injection, but I did not realize you could use it to positive effect on a normally aspirated engine.