What exactly "contains 10% ethanol" do?

[peterbrown77]

First, the problem is the gage, not the gas. I've never had a car whose gage was linear. I usually experience the opposite though. My Explorer will go about 250 miles on a tank. The first quarter (on the gage) gets me about 100 miles, then at half I've done about 180 miles. The remaining 70 miles move the needle from 1/2 to empty. It's very typical.

Second, the other problem with ethanol (and MTBE as well) aside from it's lower specific energy, is that it creates a "lean" condition in the exhaust stream. In fact, the old trick to get your clunker to pass emissions was to dump a lot of dry gas in the tank (alcohol) to clean up the hydrocarbons. When the oxygen sensor detects this, it holds the injectors open longer resulting in a significant decrease in fuel economy across the range.

However, since it makes Al Gore and the environmentalists happy, and certainly makes the corn farmers in Iowa happy (no coincidence about that first-in-the-nation primary), we continue to pay not only 10 or 15 cents more per gallon at the pump for the ethanol but we have to buy more of it in turn. It's a win-win for everyone. Except the driving public.