S.C. vette

jackthelad

When the C5's were first out and about, fuel contained MTBE as an additive both to enhance octane and meet the oxygenation requirements of various legislation.

For some history, see : http://www.fuel-testers.com/ethanol_...cohol_gas.html

Ethanol kicks up the octane, but lowers the Btu content and so lowers fuel economy. 10% is the standard mix, as that is what all the manufacturers agreed would cause no harm to vehicles not designed for ethanol. Beyond that, and the typical problems are with plastic or rubber fuel line components. Flex fuel vehicles are engineered for E85, or 85% ethanol, 15% gasoline.

Personally, I've always suspected that the Ethanol initiative was (and is) just a subsidy for the corn belt states, especially as more energy is needed to produce the stuff than it actually contains.

gimp

The ethanol initiative is definitely a subsidy for farming, though a lot of ethanol comes from things that aren't corn (like switchgrass ethanol.)

In my opinion, getting most cars to either run on 85% ethanol out of the box or with very little change is a big strategic benefit to the US - if something goes really bad with oil producing countries, they can very quickly reduce the reliance on oil for transportation. (Of course, since the strategy started, we've found ways to produce a lot of our own here and in canada.) You have to admit it's actually a good backup plan.

Now that that's been accomplished, I see fairly little reason to bother with ethanol other than to keep the strategy alive and the subsidies alive.

I would like to see ethanol-free fuel become somewhat accessible again for reasonable prices outside of areas where it's required (lots of farm areas sell ethanol-free fuel, which makes sense), but I also want 93 octane, and living in california I bet I'll get neither any time soon!

CaliforniaJack

The hydrocarbon mixture that we call Gasoline has more energy per unit volume than Octane (C8H18) or Ethyl Alcohol. So a gallon of 87 octane gas has more energy than a gallon of 91 octane gas. The only reason we add Octane is to prevent pinging from pre-detonation. Ethyl Alcohol burns more completely, so it pollutes less, but it has the least energy content. The use of any more Octane or Ethyl Alcohol than needed to prevent pre-detonation will result in lost power.

captaineddie

I would do some tests with the car using both types of gasoline. Check mileage and listen to the engine and decide for yourself which seems best for you and your car.