What is it?
Nearly all car enthusiasts will, by now, be familiar with the radical BMW i3. Announced as the ‘Mega City Vehicle’ just over three years ago, the electrically driven production version is finally on sale in the UK.
Based on a separate aluminium chassis, topped with a carbonfibre reinforced plastic bodyshell, the i3’s rear wheels are driven by a rear-mounted electric motor, good for a peak power output of 167bhp and 184lb ft of torque from standstill.
This model is the i3 Range Extender, which gets a two-cylinder petrol engine/generator to act as back up to the 18.8kWh lithium-ion battery. The two-cylinder, 647cc engine - adapted from a BMW scooter - is made in Korea to BMW’s specifications and develops 36bhp and 40lb ft of torque at around 4500rpm, which seems to be the speed that the engine is programmed to run at when it is called into use.
Described as being ‘sealed in a box’ under the rear boot floor (although it sits alongside the electric motor), the petrol engine (which already meets strict EU6 pollution regulations) cannot mechanically assist by driving the rear wheels. This is in contrast to the Chevrolet Volt, whose range-extender engine can actually ‘clutch on’ to the transmission.
The i3’s tiny engine/generator gets an equally tiny nine-litre fuel tank and what one BMW employee told me was a “real-world economy of between 40 and 50mpg” when driving the i3 purely on the engine alone. Officially, this car is rated at 470.8mpg.
On paper, there are downsides with the addition of the range-extender engine. Weight rises from the 1195kg of the pure EV i3 to 1315kg. This very slightly blunts performance, with this version of the i3 having its 0-62mph sprint time increased from 7.2sec to 7.9sec, while the crucial urban 0-37mph time is eased back from 3.7 to 3.9sec.