[Christ]

Just to point out that acetone in racing has nothing to do with engine efficiency -

N-heptane is also used in racing, along side PURE Xylene (which has a very high octane rating, ~118, IIRC).

Why use something which has 0 Octane? Because there were rules in F1 that kept the maximum octane at a certain level, and a tank full of Xylene was too much, so you add N-Heptane, which is basically inert, and it brings you under the average octane rating for the rules.

They don't do this anymore, that I know of, but they also don't use acetone on a wide scale, unless they need the extra octane on a really hot day, etc... it's not for efficiency at all, rather for keeping the engines from blowing up.