boocoodinkydow wrote:
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actually pretty simple to summize. an 8000' decline over 35 miles isn't going to be a consistant linear decline that's going to allow a constant downhill coast. it's surely going to be a series of inclines & declines. sliding downhill will surely achieve 30 mpg or greater but as soon as it hits an incline, with all your experience, you know it's definitely going to dip deeply into the single digit zone with that weight hung behind it. hope this helps.
and seems as good of a real world comparison as you could ask for outside a vacuum.
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A simple test over the same stretch, even on different days with different conditions is far more comparable than anecdotes derived towing with one vehicle uphill, and one going down.
Fact is the un-throttled vehicle with the smaller engine will tend to coast more efficiently, giving it a huge advantage downhill, which is part of the reason small boosted engines theoretically get better mileage than larger un-boosted engines. Smaller loads are when diesels operate much more efficiently, with minimal pumping losses, as they are not fighting throttle plate restriction.
Again, the ED (which shares a common symptom as an affliction with the same abbreviation), will ALWAYS get better mileage. It would be nice to see what the difference really is, when it is compared without someone looking for a certain result.
Unfortunately, Consumer Reports may have to answer this one, as useless as they are at many things, they excel at generating date when they do it. They debunked the theory that the EB got worse towing mileage than a typical gas V8, because they compared it without bias. (No way to favor the Japanese when it's 2 Fords, ya know...)
