Quote:
Originally Posted by ecomodded
Well that's no fun is it.
I think your forgetting that work or force is not done without energy , adding a wind load will not benefit fuel economy , removing wind load will. Driving at 1500rpm will save fuel over driving at 2500-3500 because it takes more fuel to drive at higher rpm's.
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my point was that operating an engine far from its peak volumetric efficiency...is NOT as efficient. Even if it burns less fuel overall, but it's burning it LESS efficiently. rpm is not the determining factor (although there is slightly less engine friction to overcome). A car needs a certain amount of HP to cruise at a given speed and load. A downsized engine tuned to make just enough HP at cruise rpm, and peak VE, is the most efficient option. engine tech and driving style have more impact on consumption than a few counts of Cd.
My other point was, that OEMs know that aero doesn't make much difference at 60 mph...that's why they don't try. In city, it makes no difference at all, and hardly impact EPA mixed cycle ratings. Low Cd is more a marketing tool than anything.