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From.. http://en.wikipedia.org/wiki/E85
Maybe I will try running it in my car when it gets warmer. [img]smile.gif[/img]
E85 gives particularly good results in turbocharged cars due to its high octane [3]. It allows the ECU to run more favorable ignition timing and leaner fuel mixtures than are possible on normal premium gasoline. Users who have experimented with converting OBDII (i.e., On-Board Diagnostic System 2, that is for 1996 model year and later) turbocharged cars to run on E85 have had very good results. Experiments indicate that most OBDII-specification turbocharged cars can run up to approximately 39% E85 (33% ethanol) with no CEL's or other problems. (In contrast, most OBDII specification fuel-injected non-turbocharged cars and light trucks are more foregiving and can usually operate well with in excess of 50% E85 (42% ethanol) prior to having CEL's occur.) Fuel system compatibility issues have not been reported for any OBDII cars or light trucks running on high ethanol mixes of E85 and gasoline for periods of time exceeding two years. (This is likely to be the outcome justifiably expected of the normal conservative automotive engineer's predisposition not to design a fuel system merely resistant to ethanol in E10, or 10% percentages, but instead to select materials for the fuel system that are nearly impervious to ethanol.)
Fuel economy does not drop as much as might be expected in turbocharged engines based on the specific energy content of E85 compared to gasoline, in contrast to the previously-reported reduction of 23.7% reduction in a 60:40 blend of gasoline to E85 for one non-turbocharged, fuel-injected, non-FFV. Although E85 contains only 72% of the energy on a gallon for gallon basis compared to gasoline, experimenters have seen much better fuel mileage than this difference in energy content implies. Many automotive writers and columnists suggest that because of the lower energy content, you should expect an equivalent 39% increase in fuel usage. This has not been observed in practice when running gasoline and ethanol blends. Some of the newest model FFV's get only about 7% less mileage per gallon of fuel of E85 compared to their gasoline fuel mileage.
The reason for this non-intuitive difference is that the turbocharged engine seems especially well-suited for operation on E85, for it in effect has a variable compression ratio capability, which is exactly what is needed to accommodate varying ethanol and gasoline ratios that occur in practice in an FFV. At light load cruise, the turbocharged engine operates as a low compression engine. Under high load and high manifold boost pressures, such as accelerating to pass or merge onto a highway, it makes full use of the higher octane of E85. It appears that due to the better ignition timing and better engine performance on a fuel of 100 octane, the driver spends less time at high throttle openings, and can cruise in a higher gear and at lower throttle openings than is possible on 100% premium gasoline. In daily commute driving, mostly highway, 100% E85 in a turbocharged car can hit fuel mileages of over 90% of the normal gasoline fuel economy. Tests indicate approximately a 5% increase in engine performance is possible by switching to E85 fuel in high performance cars.
Fuel economy does not drop as much as might be expected in turbocharged engines based on the specific energy content of E85 compared to gasoline, in contrast to the previously-reported reduction of 23.7% reduction in a 60:40 blend of gasoline to E85 for one non-turbocharged, fuel-injected, non-FFV. Although E85 contains only 72% of the energy on a gallon for gallon basis compared to gasoline, experimenters have seen much better fuel mileage than this difference in energy content implies. Many automotive writers and columnists suggest that because of the lower energy content, you should expect an equivalent 39% increase in fuel usage. This has not been observed in practice when running gasoline and ethanol blends. Some of the newest model FFV's get only about 7% less mileage per gallon of fuel of E85 compared to their gasoline fuel mileage.
The reason for this non-intuitive difference is that the turbocharged engine seems especially well-suited for operation on E85, for it in effect has a variable compression ratio capability, which is exactly what is needed to accommodate varying ethanol and gasoline ratios that occur in practice in an FFV. At light load cruise, the turbocharged engine operates as a low compression engine. Under high load and high manifold boost pressures, such as accelerating to pass or merge onto a highway, it makes full use of the higher octane of E85. It appears that due to the better ignition timing and better engine performance on a fuel of 100 octane, the driver spends less time at high throttle openings, and can cruise in a higher gear and at lower throttle openings than is possible on 100% premium gasoline. In daily commute driving, mostly highway, 100% E85 in a turbocharged car can hit fuel mileages of over 90% of the normal gasoline fuel economy. Tests indicate approximately a 5% increase in engine performance is possible by switching to E85 fuel in high performance cars.
