ethanol’s energy content was not found to be a direct predictor of fuel economy. A fuel’s energy content in British Thermal Units (Btu) is current standard practice for estimating fuel economy, a method that, because of ethanol’s lower Btu value, leads to estimates of decreased fuel economy in proportion to the percentage of ethanol in the fuel blend.

• This research, however, did not find ethanol’s Btu content to be a direct predictor of fuel economy. All four vehicles tested exhibited better fuel economy with the ethanol blends than the Btu-value estimates predicted. 
•  E20 and E30 ethanol blends outperformed unleaded petrol in fuel economy tests for certain autos. Contrary to Btu-based estimates of fuel economy for ethanol blends, three of the four vehicles tested achieved their highest fuel efficiency not on petrol, but on an ethanol blend. Mid-level blends of ethanol E20 (20% ethanol, 80% gasoline) and E30 (30% ethanol, 70% petrol) offered the best fuel economy in these tests.
• E30 offered better fuel economy than petrol (a 1% increase) in both the Toyota and the Ford.
• E20 offered better fuel economy than petrol (a 15% increase) in the flex-fuel Chevrolet.
• The non-flex-fuel Chevrolet more closely followed the Btu-calculated trend for fuel economy, but did experience a significant improvement over the trend line with E40 (40% ethanol, 60% petrol), indicating that this may be the “optimal” ethanol blend level for this vehicle.

Standard, non-flex-fuel vehicles operated well on ethanol blends beyond 10 percent – All automakers currently cover the use of up to E10 (10% ethanol, 90% petrol) by warranty for standard, non-flex-fuel vehicles. In this preliminary research, the three non-flex-fuel vehicles tested each operated successfully on ethanol blends significantly higher than this 10% ethanol level.

• The Ford Fusion operated on E45, the Toyota on E65, and the non-flex-fuel Chevy on E55. No engine fault codes were displayed until these levels were surpassed.

So if many cars are demonstrating such better performance on E20 and E30 -- imagine how well they'll be able to perform on E85. And the higher the ethanol percentages, the lower the driver's fuel costs will be. As well as helping the environment more, and supporting our increasing independence from oil rich countries. Remember to get your vehicle properly fitted with a flex fuel kit, however: in order to achieve its full efficiency. Within just a few tankfuls, the kit will pay for itself. From then on, it's all purely savings.



Related reading:

Full report is available here.

The above information was obtained from The American Coalition for Ethanol (ACE) website www.ethanol.org