BMW's new petrol-electric roadster has been anticipated as the German car maker looks to build a group of environmentally friendly vehicles under its new i badge. A BMW i3 city car and BMW i8 coupe will kick off the new range next year, followed by the i8 Spyder, a year to two behind, and expected i1, i5 and i7 models.
The i8 Spyder is a touch shorter in length and wheelbase than the coupe, and features a two-seater layout rather than the 2+2 configuration of its fixed-roof sibling. There are also more conventional-looking versions of the i8's scissor doors compared with the transparent doors of the i8 coupe concept.
BMW hasn't revealed details of a roof system for this open-top i8, though the concept features twin-humped bodywork behind the seats that incorporate roll-over hoops.
The plug-in hybrid i8 Spyder naturally shares its drivetrain with the coupe, and comprises a 96kW electric motor that powers the front wheels and a 164kW 1.5-litre three-cylinder petrol engine that looks after the rear wheels.
The three-cylinder will have wider usage in the BMW Group, with the engine making its way into the 2014 Mini and a new front-wheel-drive BMW with which it will share its underpinnings. There will also be three-cylinder turbo diesel versions.
BMW says the combined output for this hybrid - unlike some other hybrids such as the Toyota Prius - is a straight addition, with 260kW for the sports car that can be driven either by the front, rear or all four wheels. Torque is rated at 550Nm.
The 1630kg BMW i8 Spyder will hit 100km/h from standstill in 5.0 seconds flat, says BMW, matched by quick in-gear acceleration that sees the 80km/h become 120km/h on the speedo in 4.0 seconds. Top speed is an electronically governed 250km/h.
A perfect 50:50 weight distribution and a low centre of gravity created by the i8 Spyder's super-low, 1208mm height should lead to trademark BMW handling qualities.
Fuel consumption is rated at a remarkably low 3.0 litres per 100km, while the BMW i8 Spyder can travel for 30km on electric power alone. The Spyder's lithium-ion battery pack can be recharged in just two hours using a conventional household power socket.
The i8 Spyder follows the coupe in using a new exterior layering effect created by overlapping panels that benefit aerodynamics and is a design concept that will be seen on future versions of regular BMWs.
The BMW i8 twins are similarly constructed, with a carbonfibre-reinforced-plastic body built upon an aluminium platform.
Carbonfibre can also be found in the two-seat cabin, along with plastic and leather.
The BMW i8 Spyder features a flat glass panel at the rear, with a shallow 100-litre luggage section. The concept features two electric 'kick board' scooters under the transparent cover (pictured above).
BMW Australia has already suggested pricing for the i8 coupe would be about $300,000, and the Spyder would be expected to carry a premium.
Spied: BMW i8 Coupe