[Christ]

Ok, now that that's cleared up, water in fuel without being specifically emulsified can be and normally is a bad thing.

Using water in the intake stream to help cool the combustion sequence and provide an extra charge is not a bad thing, but can be, if done improperly. The only real tuning required is "does it run right" tuning.

Specific emulsions have been tested to no end, so far, as fuels for different types of engines, which provide a power generation advantage in making the same power for less fuel (torque as energy per BTU of fuel consumed... it changes the BSFC map considerably), as well as lowered emissions per gallon of mixed fuel burned. (I believe the emissions rate is the same per gallon of fuel non-mixed, but for the complete emulsion, per gallon, the emissions rate is lowered). There are economy and power differences on a per-gallon basis, which is where the problems come in, when testing emulsions versus standard fuels.

Those links I posted earlier in the thread lay out some of that information for you, and you can find many many more on the same topics with quick searches on Google.