When General Motors got to work seriously changing the Chevrolet Volt from blocky concept to sleek production model, company engineers discovered that by improving the aerodynamics by 80 counts, the car netted a six mile per gallon improvement in its highway fuel economy rating (note: a "count" is a thousandth of a point of a Cd number, so reducing a Cd of 0.150 by 50 counts would give you a Cd of 0.100). On the flipside, taking out 400 pounds of stuff only improved the car's highway mpg by one mile a gallon, though that's largely because of the Newtonian "an object in motion tends to stay in motion unless acted upon by an outside force" hubbub. The lesson for the Volt? Aerodynamics beats weight reduction as a way to increase efficiency.
Not everyone agrees that aerodynamics are key to better cars, however. On the performance side of things, let's not forget Enzo Ferrari's famous (and wrong) quote: "Aerodynamics are for people who can't build engines." When it comes to building more fuel efficient cars, weight reduction can play a big role. Lotus, in particular, is a big proponent of shaving pounds from its sportscars. The Elise Club Racer, to cite just one example, weighs less than 2,000 pounds.
Today, Lotus Engineering and the International Council on Clean Transportation released a study that found that weight reduction should not be forgotten and is, in fact, a cost-effective way to improve fuel efficiency. Specifically, the engineers calculate that you can have a "vehicle mass improvement" of 38 percent compared to a conventional mainstream vehicle (in this case, a Toyota Venza) and that it can be achieved with "only" a three percent increase in component costs. One important detail: this is "using engineering techniques and technologies viable for mainstream production programmes by 2020." Even though 2020 is a decade away, it's interesting to see how much fuel might this save. The DOE estimates that reducing a vehicle's mass by 33 percent means a 23 percent drop in fuel consumption. Not bad. Find more details after the jump.