[SEL] semi OT - acetone in gas for cleaner, better running?

[Richard Allen]

Hi, Bill,

>From a chemical standpoint, acetone is a ketone, which is a class of
oxygen-containing compounds based on hydrocarbon molecules.
Specifically it is methyl-methyl ketone or dimethyl ketone. Another
well-known ketone with somewhat similar properties is methyl-ethyl
ketone or MEK. Acetone is produced by the body naturally (called
ketosis) during the breakdown of fats when they are metabolized for
energy and can often be smelled on the breath and mistaken for alcohol.
Diabetics also produce acetone when their insulin levels are low, which
is from the forced metabolism of body fats for energy because glucose
is not available. Acetone is a poor solvent for a lot of things in
general, but for a few materials it is an excellent solvent, or the
only commonly available solvent that works for things like oxidized
gasoline gums, epoxy, polyester resin, and instant setting glue. It
works for dissolving the gummy residues that used to build-up in
gasoline systems and be a problem, but modern gasolines contain
adequate oxidation inhibitors and detergents to prevent that sort of
thing nowadays for the most part. A lot of engine performance additive
product sales depend on older people’s memories of the gummy gasoline
and lousy lubricants that USED to be the only products available, but
all that has changed with additives meant to maintain fuel injection
systems for the gasoline engines that run slightly hotter nowadays. As
far as an octane booster goes, I don’t have any idea how well it would
work, but I have run straight acetone in an old Honda 150 motorcycle
with a compression ratio of 8.5 to one and it didn’t knock at all. I
would be very hesitant about using acetone in a modern fuel system
because of the many elastomers or plastics used in the fuel delivery
systems nowadays. For the old fashioned copper tubing, cast iron, zinc,
and aluminum bodied carburetors, steel parts, glass sediment bowls,
cork gaskets, etc., acetone won’t cause a problem. I would imagine that
its ultimate combustion characteristics are similar to ethyl alcohol
and adding it to gasoline would affect engine performance in a similar
manner. If a large amount of acetone is added to gasoline the
carburetor would need to be adjusted to enrich the mixture since
acetone and alcohol burn lean compared to gasoline. With my Honda
motorcycle I had to raise the carburetor-metering needle up several
notches to get the mixture rich enough for the engine to run right with
straight acetone or ethyl alcohol. That very wide adjustment capability
of the Kehin-Seiki carburetors makes them very versatile because of the
very wide variety of fuels they will effectively carburet. 

Richard Allen