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Old 02-17-2014, 11:56 AM   #74 (permalink)
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Location: lakewood, co, usa
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subey - '99 Subaru Impreza Outback Sport

rav4 - '07 Toyota Rav4
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Way to go davelobi, the threads been dead for 6 days and you woke it up

I may think me stupid because I don't get it, but I've tried to understand this technique but no one has been able to explain it using the fundamentals of physics/engineering, or test data, I'll take either. It's mostly faith based, myth and lore. The descriptions of what DWL is are all over the place.

There are cases where it makes sense, but it doesn't make sense as a general rule. It probably makes sense on low grade rolling hills, but that's a special case. My rav4 is geared really high and it wants to shift down at the slightest whim, DWL works sometimes.
Here's what I think makes sense: do what it takes to stay in high gear on the climb and neutral on the downhill. Depending on the hill and the vehicle that may be WOT or DWL.

Perhaps there's a fundamental misunderstanding. Perhaps it works when you allow the speed to drop to something really slow like 30mph instead of reasonable highway speed. I'm not willing to do that so that means I'm not a hard core hypermiler, I'm just trying to get from A to B efficiently. Just as there is an optimum cruising speed somewhere in the range of 45-55 there must be some optimum speed for a climb and I don't know what that is. I think in my intial post I said that I was looking at the trade off between fuel consumption and travel time, if all you want is maximum fuel efficiency and that means going 20 mph up a hill, then perhaps DWL is the way to go.
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