Some thumbnail ethanol info.
Ethanol - ethyl alcohol - is an "oxygenate" - it contains some of it's own oxygen required for combustion - and it functions in your engine as a combustion promoter/flame front stabiliser, giving a higher apparent octane rating (a measurement of a fuels' tendency to resist "knock" in a very specific set of circumstances).
It has become popular lately because the oygenate MTBE (methyl tert-butyl ether) that was prviously in vogue with the clean-air set was found to be migrating from it's storage tanks into the water table with frightening regularity...
All these things were originally brought on line to replace the big-daddy octane booster of all time... TEL, tetra-ethyl lead, which allowed you to blend poor quality gasoline and bang up the octane number with an additive. It is perfectly possible for a refiner to make 100 octane gasoline, without additives! But it costs...
Ethanol will not give your engine more power, unless you have a high-performance, high compression, turbo- or supercharged engine designed to make use of high octane fuels, and optimised for ethanol.
A volume of Ethanol contains less energy than an equal volume of gasoline. Therefore, fuels containing ethanol will get a lower mileage than a fuel with no ethanol. The higher the percentage of ethanol, the more apparent this difference will be.
100% ethanol can be used as a motor fuel. E85 is a way of easing the hard cold-starting problem, and to stop people from performing a simple re-refining step - and drinking the resulting product...
100% ethanol is also hygroscopic, meaning it will suck moisture right out of the air, in the process decreasing it's quality as a motor fuel, and causing it to become corrosive.
Although ethanol fuels contribute less to the greenhouse gases, when adding in all the other energy inputs into the production of ethanol, it can often seem to be far less environmentally friendly than is touted. Go right back to the diesel used in the tractors in the field, and the use of chemical fertilizers, pesticides, and herbicides (all derived from oil), transportation by truck or rail to the refinery.
Plus - at the end of the day, it costs more to produce a gallon of ethanol than a gallon of gasoline and you get less mileage - less than half, under certain conditions, hence a higher price per mile, no matter the cost at the pump.
Now - biodiesel is another story. On a pound for pound basis, it is a better alternative fuel than diesel derived from crude oil, for a lot of different reasons than ethanol, mainly having to do with energy density.
Having said all that, very cool photo of an early purveyor of home-grown fuel.
[This message has been edited by silent chief (edited 09-25-2006).]
[This message has been edited by silent chief (edited 09-25-2006).]
