Will ethanol damage my car?

You can go to any GM dealer right now and buy a car that will run on either gasoline or E85, a fuel that is mostly ethanol.  If you buy gas at almost any pump, you are running on a mixture that is up to 10% ethanol as it is.

You cannot run E85 in a car that isn’t set up for it because of differences in the programming required for fuel injection.  E85 and gasoline have different stoichiometric ratios, roughly 14.7 by weight for gasoline, 9.0 for ethanol.  In plain language, to achieve ideal combustion, more E85 must be injected into the mix than gasoline, when you’re running on it.  The computer must adjust the injector pulse width to produce the correct air/fuel ratio for each fuel.  In a vehicle that’s not designed to burn E85, the mixture would be wrong.

There are also some physical requirements in engine and fuel system design that must be considered.  Alcohol will damage some substances, like rubber, that gasoline won’t.  However, almost any car on the road could be modified to use E85 by retrofitting the affected components with ones that are compatible with both ethanol and gasoline.  This has been done for years in cars that have been modified for racing.

Finally - what’s the best?  Ethanol burns cleaner and produces less carbon dioxide than gasoline does.  It also provides a modest increase in horsepower, but at the expense of greater overall fuel consumption.  If we could produce ethanol in sufficient quantities to supply all of our motor fuel needs, then it would be the better fuel. Unfortunately, we cannot produce it in sufficient quantities now.  Most of our ethanol comes from corn, and we don’t grow enough of it that we could divert enough into fuel production, without adversely affecting food prices.  It is also harder to transport and store. Backers of E85 are confident that these problems can be solved, but I remain skeptical.

This is one of my SME areas... I am designing and building a "Flexfuel" road rally racer...

 

Ethanol, aka Grain Alcohol, is the same alcohol we drink to get drunk (if you want to take it that far).  It is "denatured" to make it undrinkable so it can be sold without worry of abuse.  For cars it is sold as E10, E85, E100... etc.  This means "E-Ethanol" and 10%, 85%, 100%.... with the other proportion being gasoline.  Alcohol will carry an electrical current and gasoline will not so the higher the percentage of alchol the more "galvanic corrosion" you get in your fuel system due to electrical current between unlike metals and also erosion of incompatible materials.  Incompatible material are rubber and aluminum which alcohol is exceptional hard on over time.  Basically the materials that are good to use in gasoline systems are bad to use in alcohol systems and vice versa. Most fuel systems not rated as "flexifuel" have incompatible materials in them.  Running even 10% Ethanol (common these days) will have an impact on your car and reduce its useful life.  There are also other problems... alchohol runs at about 19:1 parts (alcohol to air--by weight) gasoline at 14.7:1... so by running alcohol you are running lean...and the float that tells your system when the carburator float bown is full is no longer correct because of density differences.  Electronic fuel injection systems can make on-the-fly adjustments to air fuel ratio because of a closed loop in the computer that constantly takes a measure of the oxygen levels in the exhaust gas and if there is oxygen then knows the system is running lean and increases the fuel amount injected.  Running alchohol also decreases your fuel economy somewhat... pure E100 fuel econonmy is terrible (about half that of gasoline).  The performance you can get out of alchohol is better with an Octane equivalency of about 108 octane for E100... about 103 for E10 (pump gas available nationally with Ehtanol).  I can stand behind everything I have said above.