Quote:
Originally Posted by shovel
Ethanol has far fewer BTU's per pound, which is why you have to burn more of it to accomplish the same work.
But ethanol also has a higher resistance to predetonation (octane) which allows more aggressive ignition timing, and provides smoother/more even burn - as well it brings a lot of its own oxygen to the party so it increases the volumetric efficiency of the engine.
As a side note, gasoline burns most completely at its stoich. ratio of around 14.7:1 at sea level. But it releases the most BTU's per pound at around 12:1 so on paper, you should be able to return better fuel efficiency when running rich than when running lean.  |
This site has a DOE based (link invalid) number of 65.5% for the BTU energy content in E85. 65.5%, yet all Flexfuels get at least 70% of their gasoline fuel mileage. The power does make a difference
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This thread over at turbobricks is dedicated to converting to ethanol. Getting a flexfuel setup is still the hardest part. The guy running the guide is stating the stoich for E85 is closer to 8.6:1. He's also saying that EFI is designed to burn the fuel as close to Lamda as possible and any liquid fuel can be run if you size the injectors close enough. Anyone ever heard of such a thing being capable with EFI? I think this part about EFI is what people miss when they get stuck on the adjustability of carburetors.