So, DR, OCG, are you folks stating the acetone may not offer mileage enhancement if one is already using a higher octane fuel, or won't help if someone has a V-8?
Would you be suggesting only lower octane fuels that "explode" be utilized with a blend of acetone?
I admit - I'm confused.
From reading the article, the acetone is to enhance the atomization of the injected fuel, which is independent of octane's properties of retarding combustion.
Octane rating refers to how (un)likely the fuel is to detonate, as opposed to burn, in the engine. Detonation is combustion-by-shockwave, also known as "knocking" and is very bad for engine longevity. It isn't directly related to energy density or utilization. High octane fuels knock less, or not at all (even with higher-compression engines) but they won't necessarily give you any more miles per gallon. In principle, you could have a low-energy fuel (that is, that doesn't give you many miles per gallon) that knocks terribly, and another with comparably poor mileage that, however, doesn't knock at all. These would be two fuels with low and high octane ratings, but low gas mileage.
This article alleges that one gets better gas mileage by adding acetone, without making any statement about octane rating.