Water injection increases thermal efficiency; the heat that would go out the tailpipe is used to heat the water to steam which increases cylinder pressure etc. It has nice anti-detonation features too. If I recall correctly it was big in WWII aircraft, but combustion science and turbocharging mainly did it in; turbochargers turn "waste" exhaust heat energy into intake air which is a huge help at high altitudes obviously. ALso water injection was big back in the days when ignition timing was not very well controlled, usually retarded, and compressions were really low. I would suspect that today, short of well-timed direct cylinder water injection, that a lot of ignition timing work would do better than the water -- on a modern (1960's+) motor. _______________________________________________ Amc-list mailing list Amc-list@xxxxxxxxxxxx http://www.amc-list.com/mailman/listinfo/amc-list