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duffman: "steep declines will accelerate the car providing free energy"
Understood. But cresting the hill at 45 mph could still give me a much better downhill glide, as compared with cresting it at 25 mph (and consider how a roller-coaster works; the 45 mph might be exactly sufficient to send me over a subsequent hilltop). Obviously this analysis varies with the conditions. If right over the crest is a very steep downhill grade, then my extra momentum going uphill quickly is wasted, because I might need braking (regular brakes or engine braking) to avoid an unsafe speed going downhill. But my example assumes that conditions on the downhill side allow me to use 100% of the momentum I carried with me as I crested the hill.
metro: "if you're not going to glide, engine off, down the back side ... best BSFC doesn't necessarily equal lowest overall fuel consumption, it means most power produced per unit of fuel consumed"
Good point. That's very clearly said. I see exactly what you mean. It's all about planning, and strategy.
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