Join Date: Aug 2010
Location: Kansas City, KS, USA
Re: ethanol free gas
By "alcohol" I assume we refer to ethanol and/or methanol, both of which are actually great performers in internal combustion engines as borne out by the methanol and ethanol fuelled racing engines. Both ethanol and methanol has significantly higher octane ratings than "pure" gasoline, and can therefore be used in engines with compression ratios much higher than would be possible with "pure" gasoline, whether fuel-injected or carburetted.
The engine needs however to be designed or adapted for operation on pure ethanol or methanol, specifically since alcohol has a much lower heating value than gasoline requiring lower air:fuel ratios and therefore an increased volume of fuel. Advantages of alcohol as a fuel include much improved cooling, cleaner combustion, and about 20% less carbon emissions.
The reason ethanol and methanol are prohibited in aviation fuel is due to alcohol's volatility that could result in a vapor lock at altitude, its incompatibility with certain rubber materials used in the fuel systems, phase separation at altitude that may cause dissolved water to condense out of solution, and the lower heating value that decreases the aircraft's range. All factors that are irrelevant for land use.
Today's vehicle engines are designed to accommodate the alcohol/gasoline blends in use, and typically a 10-15% ethanol blend has very little impact on a modern engine, if at all noticeable. The blend does raise the octane rating by about 3 points, but one would expect slightly increased fuel consumption (about 3%) and perhaps marginal power loss if the engine management system fails to compensate for the alcohol.
I haven't found any compelling reason yet to avoid alcohol blended fuels. I certainly notice no adverse effect using it in my LT or for that matter in any of the other vehicles, motorcycles and small engines.
BMW MOA #140995
"And there is salvation in no one else, for there is no other name under heaven that has been given among men by which we must be saved."
Last edited by andres; Aug 15th, 2012 at 1:46 pm.