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Old 07-27-2009, 10:22 PM   #16 (permalink)
roflwaffle
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Join Date: Dec 2007
Location: Southern California
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Camryaro - '92 Toyota Camry LE V6
90 day: 31.12 mpg (US)

Red - '00 Honda Insight

Prius - '05 Toyota Prius

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90 day: 152.47 mpg (US)
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Quote:
Originally Posted by nubbzcummins View Post
I was using inaccurate figures for the earlier calculation. Ok here are some different figures that should be closer. At 60mpg diesel and 20mpg propane and a 3:1 ratio propane:diesel here is the math. 3 x 20 = 60 for 3 gallons of propane. 1 x 60 = 60 for 1 gallon of diesel. 60 + 60 = 120 miles.
This last part is your problem. The truck isn't using 3 gallons of propane to go 60 miles, then 1 gallon of diesel to go another 60 miles, it's using 3 gallons of propane and 1 gallon of diesel to go 60 miles. 60 miles / 4 gallons of diesel and propane = 15mpg. Or 20 mpg diesel equivalent since propane has less energy per gallon than diesel.

Last edited by roflwaffle; 07-28-2009 at 12:11 AM..
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