2015 BMW i8, 2013 Frankfurt Auto Show
As previously reported, the car goes on sale in the spring, priced from $135,925 including destination. That puts into Audi R8 and Porsche 911 Turbo territory, though the i8 stands apart due to its impressive fuel economy--in excess of 50 mpg combined. This is due to its sophisticated drivetrain that pairs a turbocharged and direct-injected 1.5-liter three-cylinder engine with an electric motor.
The engine is used to drive the rear wheels via a six-speed automatic transmission while the electric motor powers the front pair via an integrated two-stage auto ‘box. However, both power sources can work together to form a through-the-road all-wheel-drive setup. System output is 362 horsepower and 420 pound-feet of torque--enough for 0-62 mph in under 4.5 seconds and a governed top speed of 155 mph.
This drivetrain is housed in what BMW calls the “Drive” module, a lightweight aluminum structure that also houses the electronic control units, suspension components, and structural and crash protection components. Mounted on top is the “Life” module, which is essentially the passenger cell. This section is comprised primarily of carbon fiber-reinforced plastic in order to keep strength and rigidity high but weight low. The savings from this design offset the additional weight of the electric motor and battery, giving the i8 a curb weight of less than 3,285 pounds. If it had stuck with conventional steel, BMW says the i8 would weigh around 50 percent more.
For more from the 2013 Frankfurt Auto Show, click here.