Quote:
Originally Posted by nubbzcummins
It would work like that if you use equal parts of both but this is probly not the case.
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Are you sure about that? Lets construct a similar situation, but w/ the same fuel to simplify energy content issues. Lets say my car gets 25mpg. I get a gallon of fuel from Shell, Arco, Exxon, and Ned's family gas station. Then I drive 100 miles. Technically, since I used a little bit of each station's gas, I went 100 miles on Shell, 100 on Arco, etc... And since, like ya mentioned, I was using equal parts, I got 100mpg on Arco, and on Shell, etc...
Quote:
Originally Posted by nubbzcummins
Example if you use equal parts the mpg avg would be 40mpg but if you use 75% at 20mpg and 25% at 60mpg the avg would drop to 30mpg due to the amount used being weighted more towards the one that yields lower mileage. But hey, 60mpg is not bad in a big truck!
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We're using diesel at 60mpg, and a gallon of propane, be it a GGE or GDE of propane, or a gallon in terms of volume, at 20mpg. To go 20 miles, we used 1/3rd of a gallon of diesel, and one gallon of propane. If it's a gallon of gasoline or diesel equivalent propane, then we used ~37-42kWh of propane, plus another 14kWh of diesel, to go 20 miles, which works out to ~51-56kWh for 20 miles that is the equivalent of ~1.21-1.33 gallons of diesel, so over 20 miles we're looking at ~15.1-16.5mpg. If it's a straight up gallon of LPG, then it's ~28kWh of propane, plus 14kWh of diesel, for ~42kWh/1 gallon of diesel, and that's ~20mpg. Either way, it ain't 40mpg or 30mpg. ~15-20mpg is the norm for a conservatively driven pickup. Not to say that diesel pilot ignition of propane or natural gas isn't more efficient, just that it's not 30-40mpg more efficient.
Odds are the person who started that wanted to sell propane injection.