Water injection increase gas mileage and engine response (power or torque?) only if you retune your engine, mainly leaner AFR and avanced timing.
Improvments are more noticeable at low rpm and low to medium throttle. That is what I noticed on my vehicles.
The expansion into steam does not...
Interesting, this looks a lot like impedance matching on Radio electronic systems.
This is what we use to impedance match our prototype circuits:
http://www.maurymw.com/products/rfdcs/mantunrs/mntnrs3/mntnrs3.htm
This is for Radio circuit, and has nothing to do with engine, except the theory...
I used water injection in my car, and it can be done simply for about $20.
My car was dieseling all the time. Now it runs smooth.
I live in the woods, I don't have to pass emissions, but I can tell you that the engine runs much better. Just for that, you can always try water injection and see if...
