Octane has flirted with BMW’s plug-in hybrids before. Its i3 city car captured our imagination but the limitations of its range-extender powertrain frustrated as much as its endless wave of electric torque entertained. However, its bigger brother, the i8, did inspire a few of us with its combination of spaceship looks and 357bhp (228bhp from the three-cylinder, turbocharged 1.5-litre petrol engine; 129bhp from the electric motor).
BMW has now widened the appeal of its hybrid sports car with the i8 Roadster. Driven by customer demand, BMW’s first step in creating the #Roadster was literally to cut the roof off the carbonfibre-bodied coupé and see what happened. Which wasn’t much, as it turned out, so the development team embarked on creating a production-ready Roadster.
Structural changes were kept to a minimum, with the A-pillars and windscreen header gaining additional layers of carbonfibre, plus the substitution of new frameless gullwing doors. They also removed the two rear seats in order to store the electric folding fabric roof.
Beneath the carbon tub is BMW’s latest battery technology, with denser cells increasing the electric motor’s power by 12bhp, while extending both the electric driving range to 33 miles (up from 20) and the maximum speed in EV mode to 75mph.
One of the big draws of an open-top car is the exposure offered to its soundtrack. With the i8 Roadster, as it’s part-electric, you might consider that to be a redundant feature. But while there is no sonorous straight-six to enjoy, the electric whirr and the three-pot’s offbeat thrum have a unique appeal. Hooked to the i8’s slick dynamics and performance (think Lotus Elise rather than Lamborghini Huracán), the Roadster appeals and thrills on another level by comparison with its more contemporary rivals.