Quote:
Originally Posted by Saskwatchian
And this is why MPG is a stupid measurement for fuel saving.
Going from 30 to 33 mpg will save you 3 gallons in 1000 miles.
Going from 15 to 18 mpg will save you 11 gallons in 1000 miles.
3 MPG change does not mean the same thing on one vehicle as another.
If the wheelskirts were to save about the same amount on the suburban as a 30mpg car the difference would be 0.5-0.7 mpg, not an insignificant amount on a large vehicle.
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It's the percentage gain to the average mpg that matters. And that average, preferably, covers more than one year of driving where no major changes in the life of the owner/operator occurred. December was the same as the previous January for what, where and how.
And it isn't the "gallons saved" so much as
it is the reduction in the fuel portion of the ownership/operating cpm of the vehicle..
X percentage gain translates to Y cpm
We think that fuel economy is important, but it is relative to all other costs. A reduction to 15-cpm on fuel from 17 is great . . but is the rest of the vehicle an 87-cpm burden?
The modifications which positively affect reliability & longevity (components such as tires & brakes), etc, is
where the money is.
Fuel economy is just a nice way to track the thing.
And some manner or methods of "saving fuel" are detrimental to overall vehicle condition, performance and life. They are not, thus, "
economical even though a bit of fuel has been saved.
.