BMW‘s showdown continues with the presentation of its i8 Concept, a plug-in hybrid sports coupe that joins the i3 pure-electric hatchback to form the first models of the Bavarian firm’s i sub-brand.

The i8 Concept is a further development of the 2009 Vision EfficientDynamics study and it opens the way for a production model, which is scheduled to arrive in showrooms in 2013.

The sportiest member of the i series models combines the modified electric drive system from the i3 Concept, but this time fitted over its front axle instead of the rear, with a high-performance, 1.5-liter turbocharged three-cylinder gasoline engine (in place of the Vision ED’s diesel unit) developing 220HP (164kW) and 300 Nm (221 lb.ft) at the rear.

The gasoline unit drives the rear wheels through a dual clutch transmission, while the electric motor uses a twin-speed transmission to motivate the front wheels.

Working in tandem, the two drive systems produce a combined output of 349-horses and 550Nm (405.6 lb.ft) of peak torque offering coupe model a 0-100km/h (62mph) acceleration time of just 4.6 seconds and an electronically governed top speed of 250km/h (155mph).

At the same time, BMW says the i8 returns an impressive combined fuel economy in the European cycle of 2.7 liters per 100km (approx. 87mpg US or 104mpg UK).

The i8’s electric motor is fed by a large lithium-ion battery, which can be fully charged from a domestic power supply in 1 hour and 45 minutes, offering a pure electric driving range of up to 35 km (approx. 20 miles).

BMW says the positioning of the electric motor and engine over their respective axles result in an optimum 50/50 weight distribution, while the extensive use of lightweight materials including aluminum on the chassis and CFRP (carbonfibre reinforced plastic) on the body, help keep the weight down to 1,480kg or 3,262 pounds.

The i8 is a 2+2 seater and measures 4,632mm long, 1,280 mm tall and 1,955 wide. The concept model will make its public debut at the Frankfurt Motor Show this fall.

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