A few thoughts on using acetone.
1) A/F ratio, Might be where the milage increase comes from. Since the atomization of the fuel is improved you get a better more complete burn. More fuel burned means more oxygen used. Does the O2 sensor read this as a rich mixture and lean accordingly? I can't think of any other way to increase the mileage. Even if the fuel is burned more completely, injecting the same volume of fuel per event will render the same consupmtion. Think about it, when the injectors are not working properly, atomization is poor, droplets are larger than normal. The larger droplets don't allow for a complete burn, leaving a surplus of oxygen in the exhaust. The O2 sensor reads this as a lean mixture and increases the fuel volume.
2) Power, better atomization means more efficient combustion, more efficient combustion means more POWER! But if I'm right about the O2 sensor leaning out the mix, would we be back to the same power output as before?
3) Flame front, smaller droplets burn faster and have less space between them. Faster flame front, more expansion from heat closer to TDC. A few more degrees of crankshaft rotation to use the higher pressure. The increase in degrees of crank rotation mean better power. The increase in pressure means better torque.
4) Inlet air temp, smaller droplets absorb heat faster. Would we actually get a denser A/F charge? I don't think it would be enough to offset the rich mix reading te O2 sensor is getting (in 1 above) but this would typically offer up more POWER!
5) Detonation, should decrease detonation. Closer droplets being closer together would give a more stable, evenly distributed mixture. Effectively reducing lean spots in the combustion chamber. A lot of the problems that cause detonation stem from lean spots in the mixture. A 'bubble in the chamber will create a lean spot, compress it and it can't take the heat like a rich mix can and it ignites.
6) Compression, will adding acetone effectively increase octane rating? Or can the more evenly distributed mix help control the combustion allowing an increase in compression? Or not?
7) ignition timing, as in the above, will this allow for a more aggressive timing curve?
All these questions were bombarding me all night. Mybrain gets on a subject and tortures me in my sleep. My dreams include visions of the subject at hand. I really hate my brain for doing this to me. Even does this with my work. Imagine dreaming about your job all night long, not women or cars, or cars or women, or maybe just cars(Bryan). I would like to be able to answer these lifes's mysteries, but I'm sure somebody somewhere already has. Either look for the answers in text, or, PLAY! I think I'll play! More fun that way!