Now in its sixth-generation, the all-new 2012 BMW 3 Series is helping to usher in a new era of efficiency, not only for Munich's most important model, but for the brand's lineup as a whole. It's a future where hyper-efficiency and dynamic ability are expected to live in perfect harmony. But can they? BMW believes they can, and is relentlessly pushing to meld the two on cars like the new 3 Series.
Due in the U.S. next February, the new generation 3 Series not surprisingly gets a unique sheetmetal treatment, with cues from the coming BMW i8 sports hybrid and big brother 5 and 7 series models. A wider, squatter take on the traditional BMW kidney grille motif takes center stage, while a pair of narrow, vertically elongated headlamps connect to the grille on each side to form one organic, flowing front end. A strip of LED accent lights sit atop BMW's now familiar twin headlight treatment within the housing, slanting inward for a furrowed eyebrow look. Opt for the xenon headlights and the inner lamps get LED halo rings. The central intake opening in the front valance of the previous model has been abandoned, and is now split into two separate openings beneath the headlights. Out back, the car's horizontally lined taillights are similar to the units found on the recently updated 5 and 7.
As is almost always the case with a new-generation model, the 3 Series gets bigger dimensionally, growing 3.66 inches in overall length, with a nearly 2-inch longer wheelbase and 1.85-inch wider track. Despite the growth spurt, weight gain is kept to a minimum, thanks in large part to the use of lighter and stronger materials including high-tensile-strength steel, plastics, advanced composites, and heavy use of aluminum in the suspension. The end result is a body that's 10 percent more rigid and as much as 88 pounds lighter compared to a similarly equipped previous-gen model, according to BMW.
Reducing weight means improving efficiency. So does improving aerodynamics, and the 2012 3 Series benefited from full-scale wind tunnel testing, helping to further streamline body panels and sculpt the underbody for improved airflow. BMW claims a drag coefficient of 0.26, which puts the new 3 Series in the same league as hybrid hyper-milers such as the Toyota Prius and Honda Insight.
But it's with the new car's updated powertrains where the biggest EfficientDynamics gains lie. The big news under the hood of the 2012 328i is the addition of the same turbocharged 2.0-liter I-4 that debuted in the Z4 sDrive28i earlier this year (the first I-4 in a 3 Series since the E36-generation 318i), producing 240 horsepower and 260 lb-ft of torque - a gain of 10 hp and 60 lb-ft over the naturally aspirated 3.0-liter I-6 it replaces. Thanks to the twin-scroll design of the new base engine's turbocharger, peak torque is achieved at 1250 rpm and doesn't drop off until 4800 rpm. In addition to the novel design of the TwinPower turbo, BMW pulled from its usual bag of power and efficiency tricks for the four-cylinder, employing direct injection, double-VANOS variable cam timing, and Valvetronic variable valve timing. The payoff is a claimed zero-to-60 time of 5.7 seconds along with improved fuel economy that will eclipse the 18/28 mpg city/highway of the outgoing I-6, BMW says.
BMW's now-familiar turbocharged 3.0-liter N55 I-6 continues to serve duty in the 335i, with its 300 hp and 300 lb-ft of torque. Both engines are now available with BMW's eight-speed automatic transmission, which is new to the 3 Series and further improves efficiency. A six-speed manual remains as the standard gearbox. Though the gear spread is wider with the eight-speed compared to the outgoing six-speed auto, BMW says shifting is smooth and optimal ratios are available for practically any situation. A sport version of the eight-speed auto, complete with steering wheel-mounted paddle shifters, will be available with the M Sport Package.
Additional fuel-efficiency optimization tricks for the new 3 Series include BMW's Auto Start-Stop and Brake Energy Regeneration systems, and a new ECOPRO mode added to the automaker's Driving Dynamics Control system. Similar to systems popping up from other automakers, Auto Start-Stop's controller resides within the transmission and cuts engine power when the vehicle is stopped and restarts on throttle input. Brake Energy Regeneration uses energy captured through braking to help power accessory components like the air conditioning compressor, alternator, and water pump, which are also disengaged when not needed.
Select ECORPRO mode using BMW's Driving Dynamics Control switch (Comfort Sport, Sport + are the other options), and optimized throttle mapping will limit power output. With eight-speed-equipped cars, ECOPRO also shifts to a higher gear sooner and delays downshifts. When the 3 Series is operated in the mode, BMW says average fuel consumption could be reduced by up to 20 percent.