Quote:
Originally Posted by theaveng
For example the Volt that I tested:
It wasn't very aerodynamic, but still only used 5000 watts to maintain 30 miles/hour versus 50,000 every time I accelerated from a stop. A lightweight car like a smart would be about half that (which is why its EPA city score is nearly 40 mpg). IMHO weight matters more when you're constantly stopping & starting (wasting energy).
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For a lighter car, I think aero is actually pretty important around the city. I always pulse and glide because it's wasteful to run the engine at 1500rpm when it could be idling at 680. However if your aero sucks and you respect speed limits and other drivers, then you'll be cycling your engine a lot because the difference in kinetic energy that your car has between 24 and 27mph (my pulse and glide points for 25mph limits) is tiny and gets eaten up really fast. Spinning up the engine over and over adds up; spinning the flywheel to 2000rpm or 3000rpm is like accelerating a 100lb weight up to 15-20mph or so.
On the freeway you can undershoot and overshoot the speed limit a little more without causing as much trouble because there's more space and people are less pissed off. For the same reason I think pumping your tires up a lot matters more around town than on the freeway, because the further you can roll without dropping too far below the speed limit the more often you can stay in neutral.