Common car design wisdom says that a low coefficient of drag is desirable to increase fuel economy and allow for engine downsizing. At highway speeds, up to 60-percent of the power produced by the engine is used just to move the vehicle through the air.
Modern production cars typically have drag coefficients (Cd) of under 0.35, with specific examples being the Lexus GX (0.35), the Lexus RX (0.33), the Audi A5 (0.31) and the Nissan Leaf (0.28).
Reducing the Cd much below 0.25 is a daunting task that few production cars have achieved. The Toyota Prius achieves 0.25, while Tesla claims its Model S sedan will see a Cd of just 0.24. If Mercedes-Benz is accurate with its math, it has both cars beat; the upcoming CLA sedan
will reportedly have a Cd of just 0.23.
To help achieve this remarkable number, Mercedes-Benz has reduced the frontal area of the car to achieve a drag area of just 0.51 square meters. A low Cd involves more than just a reduced frontal area, however, so the CLA
gets shaped A-pillars, optimized side view mirrors, low-drag wheels and even wheel spoilers at the front of the wheel arches.
In case the 0.23 value isn’t impressive enough, the CLA 180 BlueEFFICIENCY edition (which likely won’t come to the U.S.) delivers a Cd of 0.22, thanks to a drag area of just 0.49 square meters and aero-enhancing details like grill shutters and wheel arch spoilers.
Even the underside of the CLA has received careful attention to detail, including underbody paneling (with particular attention paid to the rear axle), and a unique rear diffuser.
The net result is that the CLA will deliver exceptional fuel economy as well as a cabin that’s minimally affected by wind noise. It looks good, too, and Mercedes-Benz is betting that appearance alone will get consumers into dealer showrooms.
While Europe will get five versions of the CLA
(including a direct-injection diesel), it looks like U.S buyers will only see the range-topping CLA 250. The CLA 250 is powered by a 2.0-liter turbocharged four-cylinder engine, rated at 208 horsepower and 258 pound-feet of torque.