Methanol injectors..

[Dave Williams]

-> As with anything, there are certain penalties with the use of
-> anything -

 Besides the relatively heavy and inflexibly-sized tank and the hassle
in fueling, the major penalty is price.  Gasoline runs $1.19/gal here,
propane runs $1.80, though they price it by the pound.  For a cost
difference of $0.61/gallon it would be economical to dope the gasoline
with toluene or other octane booster as required.

 On the other hand, a propane system is a simple, effective solution to
fueling an Otto cycle engine.  If only it wasn't so expensive... <sigh>