When my car was stock I ran a water injection system and picked up some mileage when I was using it. I gave up because I always forgot to put water in it and it ran dry a lot. I also tried acetone and the two of them seemed to pick up I think 5mpg together. I was running 1 gallon of water to 10 gal of gas and 3oz acetone per 10 gallons.
Water will mix with acetone and the two of them together will mix into gasoline so would it be possible to mix up a gallon of water in 10 gallons of gas and add enough acetone to get the water to mix into the gas? It would be the simplest way to add water injection to a car.
It might be easier to experiment by trying a smaller amount of gas/water mix and seeing how the car responds to it but I might be totally nuts and the whole idea is just insane.
I remember reading years ago about some guy who was doing fuel research with caterpillar They devised a way to mix 50/50 water and gasoline. That's 50/50 by weight not volume. so it was more like 40/60 or something like that by volume. They added a secret ingredient to allow them to mix. I suspect it was acetone. Not to be a consiracy nut but the guy fell off the face of the planet in I think 99? The results they had were a cool running engine that got something like 90 percent the mileage as 100% gas. I wish I could remember his name so I could look up some facts instead of relying on my foggy memory.