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Old 10-19-2010, 02:52 PM   #279 (permalink)
Nerys
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Quote:
Originally Posted by slogfilet View Post
Just a small observation... I know there has been much talk in this thread about how ethanol contains less energy than gasoline on a pound for pound basis. Ths is absolutely true. However, I think the point is moot, as we are talking about engines that are not 100% efficient. The energy basis is known, and a 100% efficient gasolie engine will yield more power than a 100% efficient ethanol engine given the same amount of fuel.

But when the efficientcy of the engine is a variable, the fact that ethanol contains fewer BTUs than gasoline becomes irrelevant.

It is my opinion that this fact does not support nor deny any argument provided here, it just may help us avoid a red herring.
You sort of got it but the wrong way :-)

while the engine is not 100% efficient it is "x" % efficient.

lets say its 20%

20% of X energy (gasoline) is still larger than 20% of Y energy (ethanol)

there is no logical reason for the mechanical efficiency of the actual engine itself to change unless it is not compatible with the fuel (less efficient) or TUNED for the ethanol (more efficient)

but if the engine remains unchanged then its efficiency remains unchanged except for that compatibility issue if present.