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Old 07-05-2009, 03:21 PM   #12 (permalink)
Allch Chcar
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Join Date: Jan 2008
Location: North Coast, California
Posts: 429

Cordelia - '15 Mazda Mazda3 i Sport
90 day: 37.83 mpg (US)
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I wish he would report the E85 miles per gallon and not give the 100% gasoline value. His numbers are not even believable as is. And they're ruining the top 10 fuel economy with his numbers.

A commenter believes he's only using the 15% gasoline to calculate the usage. If you get 16 mpg with E85 well that's only 15% gasoline* right? Divide 16 by 15% and you get where his numbers make sense, 106 MPGe. Which is wrong because Ethanol has value too, it's not empty, it has energy. Which with 16 mpg is really 85% of Ethanol's energy 76k BTU + 15% of Gasoline's energy 116k. E85 has 70.7% of the energy content of Gasoline which means it's the miles per gallon gasoline equivalent of 22.63 MPGe. Which is only moderately better than a stock V8 at highway cruise. Theoretically it should only be 4-5% off depending on driving style but I don't believe he's running stock. His numbers for power and fuel economy line up with the theory of increasing compression ratio in an engine. Which also increase max power output.
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