You've completely lost me.
It's a method of improving the performance of an engine by injecting water (or mainly water methanol mixtures).
It uses the latent heat of evaporation to lower the charge temperature of turbocharged cars, lower temp/ denser charge/ more power!.
Turbo petrol cars are knock limited, the Research Octane Number (RON) of the fuel is very important to turbo cars, if you put a lower grade (95 vs 97) RON fuel in and the car was tuned to the edge you could destroy the engine due to detonation (the noise it produces is called Pinking/ Pinging).
Most modern cars have complex ECUs sampling the Knock Sensors (basically engine microphones) thousands of times a second, the have adaptive ignition and fuel strategies. If they see no knock they will advance timing, if they see excessive knock they will retard timing, older turbo cars are not as "intelligent".
Aquamist are a UK company who really invested a lot of time into the concept for cars (Water injection was orignally used for aeroplane engines to improve power AND reliability, the Harrier Jump Jet uses it when hovering, vertical landing and takeoff).
Aquamist supplied many rally teams until it was banned (very strange as the systems weren't really that expensive), they could push the engines a lot harder using Water Injection.
My GTO struggled to run over 12psi manifold pressure on UK fuel (97 ron). I could pull ignition timing but it feels "flat" and takes power away.
On Water Injection it could run 20psi with good ignition advance.
On my M20 petrox mixes (required fuel sytem redesign due to corrosive nature of Methanol) it has hit 30psi boost with good ignition advance and no knock.
It's really interesting to read all the early aeroplane experiments with water/ methanol injection, believe most of them were performed during the 2nd world war?. Worth a Google if you're technically inclined imho.
. They also had a fuel called optimax but ballsed up big time as that name had already been patented for a drug.. Now an eye thing ol
