Frankfurt show: More BMW i8 details emerge

BMW’s plug-in hybrid i8 supercar will outsprint the current M3, but use one-third less fuel than a Toyota Prius, when it hits Australia in the second half of 2014.

The circa-$300,000 green machine - on which several Australian have already placed deposits - will get to 100km/h in under 4.5 seconds but will use just 2.5 litres of fuel per 100km, according to newly released BMW figures.

The production i8 is expected to emerge at next month’s Frankfurt motor show - two years after the first prototype surfaced at the 2011 event.

Much of this has been chalked up to the application of lightweight materials, which have kept the kerb weight under 1500kg.

Carbon-fibre forms the main passenger cell as well as the door frames, while aluminium has been used for the body work, and magnesium for the instrument panel.

Chemically hardened glass, developed for smart-phone production, has enabled a 50 per cent weight saving over conventional laminated glass, and aluminium fasteners have been used where heavier steel was unnecessary.

Use of cutting edge materials and manufacturing methods was required to offset the weight of the i8’s lithium batteries, which power a front axle-mounted 96kW/250Nm electric motor.

Rear wheel power comes from a 170kW/320Nm turbo-petrol engine with a six-speed automatic transmission, but the i8 can run on electric alone until the 35km range of the battery has been exhausted.

The combined result of the two motors is 266kW and 570 Nm.

The 1.5-litre engine is the first three-cylinder to be used in a production BMW and produces the highest output per-litre of any BMW engine.

A complete charge of the i8 battery is possible with a standard 240-volt socket and takes under three hours, but that time can be reduced by an hour if BMW’s ‘i Wallbox’ charging station is used.

The sporty credentials continue with a near 50:50 weight distribution and the lowest centre of gravity of any vehicle in the current BMW range.