This idea has been around for a long time; pretty sure the oil companies bought up the original patents, which are probably expiring by now.
Water injection has been demonstrated to improve both power delivery and fuel economy, at least on carbureted engines. Something to do with the resulting steam improving volumetric efficiency IIRC, also improves fuel atomization and distribution.
Also cools the intake charge, always a good thing.
That said, an EFI car isn't gonna have the same fuel atomization issues, the injectors do a pretty good job, and modern engines typically have pretty good volumetric efficiency numbers stock. Cooling the intake charge can offer a pretty decent boost, tho depending on how poorly the OEM intake/airbox is designed. What's the first thing that goes on a street racer? A cold-air intake (CAI), eh?
Write back and let us know how it works , Dave. I, at least, would love to hear from someone who has tried this.
ByeBye! S.
Steve Jernigan KG0MB Laboratory Manager Microelectronics Research University of Colorado (719) 262-3101