Corn-Ethanol Lobby Hits the Blend Wall - Yahoo! Voices - voices.yahoo.com
Aside from ethanol slowly but methodically destroying all the small engines of America, there is another problem called the "blend wall." What the blend wall means is that American cars can only tolerate ten percent ethanol. Going beyond that on most conventional vehicles means that, if you put more than 10 percent ethanol in your gas tank, the auto manufacturer will not honor the guarantees they made when you bought the vehicle.
If the manufacturer found out you continuously poured water in the gas tank, they wouldn't honor the warranty either, but that's similar to what you'd be doing by using an 11 percent ethanol-fuel blend or higher blend.