The BMW i8, still the world’s best-selling plug-in hybrid sports car, has been given a mid-life update and joining the expanded i8 family is a new i8 Roadster.
Highlights of the Roadster is a fabric soft-top that can be opened/closed in 15 seconds, at speeds of up to 50 km/h. That alone is nothing unusual, but what differentiates the i8 Roadster’s soft top is the use of 3D printed aluminum components. In order to keep the soft-top’s mechanism compact, BMW had to produce geometric shaped bracing parts that are topologically optimized – a big word to describe space-efficient folding shapes – BMW had to develop a new manufacturing process.
The result is a soft-top that folds vertically in a Z, and when stowed into a the ‘roof box’ behind the driver, there’s still 92-litres of cargo space, on top of the 88-litre boot space behind the mid-engine sports car.
Changes are subtle and among the key visual identifiers of this new i8 versus the outgoing model is a model specific Coupe/Roadster badging on the C-pillar. The bonnet now features a new air shutter, which reroutes air flow to the sides of the car near the wheel arches and under the body. This aerodynamic improvement is particularly important to the Roadster variant in maintaining a comfortable cabin temperature when driving with the top down.
There are two new colour options (E-Copper metallic and Donington Grey metallic) and new optional 20-inch wheels (double-spoke for the Roadster and turbine-style for the Coupe).
Inside, the list of trim options have been revised to include Accaro interior trim, a high-end option featuring cloth/leather upholstery in an Amido/E-Copper colour scheme. The infotainment system has also been revised to bring it in-line with what’s offered in the 7 Series. The main menu is now presented on the screen in the form of horizontally arranged tiles with a live mode. The audio system features a seven-channel amplifier as well as a USB port, while there is also the option of a Harman Kardon hi-fi speaker system.
The Heads-Up Display now also shows the gear position and Optimum Shift Indicator (when the six-speed automatic transmission is in Sport mode).
There’s an audible pedestrian warning sound, which emits soft turbine-like sound when the i8 is driven in quiet electric mode. The warning sound is active at speeds of up to 30 km/h.
Both versions of the i8 continue with the same powertrain layout as before, but optimized to deliver improved performance. The mid-mounted 1.5-litre 3-cylinder engine continues to offer unchanged outputs of 231 hp and 320 Nm, but receives an integrated particulate filter to further lower emissions. In the combined cycle, the new i8 Coupe is rated fuel consumption of 1.9 litres/100km and CO2 emissions of 42 g/km; the i8 Roadster, on the other hand, manages 2.1 litres/100km and 46 g/km.
Bigger improvements are implemented on the electric half of the driveline, in which the lithium-ion battery gets its energy capacity boosted from 20 to 34 Ah and the electric motor's output raised by 12 hp to a maximum of 143 hp and 250 Nm.
On pure electric driving, the new i8 is able to reach a maximum speed of 120 km/h in eDrive mode and 105 km/h in other drive modes - either way, a significant increase from the outgoing model's 70 km/h. All-electric range is rated at 55 km for the i8 Coupe and 53 km for the i8 Roadster.