DETROIT – BMW AG rolls out the successor to its low-volume Mini E electric car at the North American International Auto Show here, dubbing it the Concept ActiveE.

Unlike the front-drive, Mini-based EV, the ActiveE is rear-wheel drive. The car is based on the 1-Series Coupe and designed to “provide a taste of a purely electrically powered BMW,” with strong acceleration and good dynamic handling characteristics.

The ActiveE also boasts rear seats, something the Mini E lost to make room for a large battery back.

Clever integration of electric drive components within the existing vehicle package of the 1-Series Coupe allows room for not only four fullsize seats but also a luggage compartment with 7 cu.-ft. (200 L) capacity.

Gaining experience in packaging electric powertrains is crucial, as the ActiveE is a test bed for powertrain components to be used on the Megacity Vehicle, a BMW EV that will be part of a new family of near zero-emission vehicles to be mass produced by the auto maker in the future.

The electric-drive motor was especially designed for the 1-Series Coupe and is located in the rear axle. It delivers 170 hp and 184 lb.-ft. (250 Nm) of torque, allowing the car to accelerate to 60 mph (97 km/h) in 8.5 seconds.

Energy for the drive system is provided by a new, advanced lithium-ion battery pack developed specifically for the ActiveE project by BMW and supplier SB LiMotive and provides a range of about 100 miles (160 km) in everyday use, the auto maker says.

The charging period also is relatively short. On the European power grid, the battery pack can be fully charged in just three hours with a current of 50 amps at 230/2340 volts. In the U.S., the battery can be fully charged in about 4.5 hours using a 32-amp residential wall box.

In another world premiere at NAIAS, BMW introduces the Z4 sDrive35is, a higher-performance version of the current Z4 with more horsepower and torque but the same fuel efficiency as the standard model.

Engineers improved intake airflow and increased turbocharger boost pressure to increase output by 35 hp and 32 lb.-ft. (43 Nm).

An enhanced engine-management system also includes an electronically controlled over-boost function that can briefly increase torque under load another 37 lb.-ft. (50 Nm), which provides a temporary torque peak of 369 lb. ft. (500 Nm) to improve acceleration. With this advantage, BMW says the roadster should be able to reach 60 mph in just 4.7 seconds.

BMW also announces here the reintroduction of 6-cyl. 7-Series sedans to the U.S. market. The ’11 740i and 740Li will feature the auto maker’s acclaimed 3.0L I-6 twin turbo engine up rated to 315 hp at 5,800 rpm and 330 lb.-ft. (447 Nm) of torque beginning at 1,500 rpm.

dwinter@wardsauto.com