Next month’s Frankfurt Motor Show will see BMW‘s new “i” sub-brand debuting not one, but its two first series production cars , the i3 electric hatchback that goes on sale this fall and which we’ve already seen, and the more hotly-anticipated i8 plug-in hybrid sports coupe that will arrive in dealerships worldwide during 2014.

BMW isn’t quite ready yet to uncover the interior and exterior styling of the i8 2+2 seater coupe, simply releasing photos of a camouflaged pre-production tester, but it is ready to share initial information and specifications.

The first thing you need to know about the i8 is that it was conceived from the outset as a plug-in hybrid sports car, with BMW looking to combine dynamic performance with green credentials.

To do that, it chose to fit the i8 with a brand-new, small displacement 228hp (231PS) 1.5-liter three-cylinder turbocharged gasoline engine sending power to the rear wheels via a six-speed automatic, and a 129hp (131PS) electric motor turning the front axle through an integrated two-stage automatic transmission. The two power systems can work independently or together with a combined output of 357hp (361PS) and 420 lb-ft (570 Nm) for full performance and all-wheel drive stability.

A lithium-ion battery that can be recharged at a standard household power socket completes the powertrain package. BMW says it is has an all-electric mode of up to 22 miles (35 kilometers) with a 3½ hour charge from a conventional 120 volt, 12 amp household circuit or approximately 1½ hours from a 220 volt Level 2 charger, increased to over 310 miles (500 km) in COMFORT mode (in ECO PRO mode, it can be increased by another 20 percent).

As Colin Chapman recognized in the early days of Lotus, a sports car doesn’t necessarily need to have an extremely powerful engine to offer performance if you pay attention to weight. BMW did that by designing the so-called Life Module that includes a carbonfibre main structure to which it attaches the carbon-fiber framed and ‘butterfly’ style doors along with the front and rear aluminum sub frames. The Germans state that the use of lightweight carbon-fiber-reinforced plastic (CFRP) for the body “brings weight savings of 50 percent over steel and around 30 percent over aluminum, with equivalent or improved strength.”

The main reason why BMW opted for these lightweight high-tech materials was to offset the additional weight of the electric motor and the high-voltage battery. All told, the i8 has a curb weight of less than 3,285 lbs (1,490 kilograms), or just 50 pounds (22.7 kg) more than the new Porsche 911 Carrera 4S PDK Coupe (3,230 lbs), which is one of the sports cars BMW has set its sights on.

So, how does all that translate in performance and fuel economy numbers? BMW quotes a zero to 100km/h (62mph) sprint time of under 4.5 seconds and an electronically controlled top speed of 250 km/h (155 mph). According to the Bavarian company, the i8 will return an average fuel consumption of under 2.5 l/100 km (over 94mpg US or 113 mpg US) with CO2 emissions of less than 59 grams per kilometer on the EU test cycle for plug-in hybrid vehicles.

By comparison, the 395hp (400PS) Porsche 991 Carrera 4S PDK Coupe completes the 0-100km/h (62mph) sprint in 4.3 seconds, tops out at 297 km/h (184 mph) and returns a combined fuel consumption of 9.1 l/100km (35.8 mpg US or 31.0 mpg UK) with CO2 emissions of 215 g/km on the regular EU test cycle.

A few other notes from BMW’s release include the car’s dimension – a length of 184.6 inches (4,689 mm), a width of 76.5 inches (1,942 mm) and a height of 50.9 inches (1,293 mm), with a wheelbase of 110.2 inches (2,800 mm), and a drag coefficient (Cd value) of 0.26.

We also learn that i8 has “a very low center of gravity and a near-perfect 50:50 axle load ratio”, and a standard DSC (Dynamic Stability Control) stability system that includes the Anti-lock Braking System (ABS), Cornering Brake Control (CBC), Dynamic Brake Control (DBC), Brake Assist, Brake Standby, Start-Off Assistant, Fading Compensation and the Brake Drying function. BMW states that the push button-activated Dynamic Traction Control (DTC) system “raises the DSC thresholds, allowing some controlled drive wheel slippage for easier start-off on snow or loose ground, or for extra-dynamic cornering.”

Further details are to be released during its world premiere in Frankfurt next month.

PHOTO GALLERY

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