The BMW i8 Roadster re-defines the art of open-topped sports car design. Jonathan Crouch drives it.
Ten Second Review
The BMW i8 re-defines the art of sports car design - both technologically and aesthetically in this Roadster guise. It may not be the ultimate contender of its kind to drive but it could well be the ultimate model of this type to own. This is, after all, a plug-in petrol/electric hybrid super sports car that runs silently on its battery in the morning commute, yet can transform itself into a high performance GT when you're in the mood.
You're looking at the future of open-topped sports cars, one that's light, strong, very fast and more than able to justify its position on the planet. Welcome to BMW's revolutionary i8 Roadster.
Originally, BMW designed the i8 as a Coupe, but showed a Spyder concept version at the Beijing Motorshow in 2012 to see if there would be enough customer interest in an open-topped version. There was and when the design team removed the roof of a fixed-top model and found the carbon fibre chassis easily stiff enough to support a convertible format, the Munich maker gave the green light for production. Following which the i8 Roadster was launched in the Spring of 2018.
It arrived on the market at the same time as the i8 Coupe was receiving a significant update and the technical changes, shared here, have been enough to further distance this i8 from its conventional super sports car rivals. In this Roadster form, you get an extra element of exotic desirability.
The i8 Roadster is something quite new: a super sports car that promises you the thrill of high performance open-topped motoring, but with near silent aural accompaniment from its electrically-assisted powertrain. That's the case when you drive this car in one of its 'eDrive' modes anyway, which work at speeds of up to 75mph and deliver top-down progress that amplifies the sights, sounds and smells of the world around you. As in the Coupe version of this model, the electric motor's sited up-front, drawing charge from a high voltage lithium-ion battery that powers the front wheels through a dedicated two-speed auto gearbox. This set-up works in concert with a tiny MINI-sourced 1.5-litre three cylinder petrol powerplant sited in a mid-engined format behind the back seats, simultaneously driving the rear wheels via another auto gearbox, this a more conventional one with 6-speeds.
This improved i8 is more efficient, but you won't be buying this BMW primarily for that. It's a super sports car after all. Which means that as soon as possible, you're going to want to click out of the standard 'Comfort' and 'ECO PRO' driving modes and snick the auto gear lever to its left hand 'Sport' setting to see what this i8 can do. As the dashboard graphics flash orange, the engine will fire up if it hasn't already, chiming in with power to the rear wheels that supplants the torque already being developed by the electric motor for those at the front. The result is 4WD traction and some serious pep, 62mph from rest achievable in just 4.6s on the way to a maximum speed that must be reined in at 155mph. The ride is rather firm, despite the standard variable damping system, and the steering could use a touch more feedback, so you don't get the trackday feel of a rival 911 or AMG-GT. In compensation though, this BMW is arguably a better highway cruiser. And on twisting secondaries, if you lower your corner entry speed a fraction, you can apply power deliciously early through the turn. That delivers an immensely satisfying feel of instant electric motor thrust which, combined with four wheel traction, makes this BMW an exceptionally quick point-to-point B road blaster.
Design and Build
Even standing still, there's a sense of theatre about this i8, with a riot of complex surface treatments, contrasting colours, sharp creases and scalloped sills. For this Roadster version, BMW has revised this car's distinctive dihedral doors to integrate frameless windows and better fit with the new roof arrangement. It's a fabric top that activates in 15 seconds at speeds of up to 31mph, folds in a Z-shape and stows vertically in the space where tiny back seats would be in the Coupe model, nestling between the rear bulkhead and the mid-rear-mounted combustion engine.
In the cabin, you'll find the styling as futuristic as it was outside, the curved, layered dash made up of overlapping three-dimensional segments and complemented by contrasting colours. Cocooned yet surprisingly roomy, the driver-focused cockpit envelopes you with slender blue-stitched leather sports seats, re-designed as part of a package of mid-term updates that also includes the standard inclusion of these carbon fibre trimming panels and the addition of touchscreen functionality for the 8.8-inch iDrive infotainment monitor positioned at the top of the dash.
Most arresting though, is the display you view through the grippy three-spoke wheel, a sci-fi-style screen, also 8.8-inches in size, which delivers range readings for fuel and battery power below two circular digital dials that change in colour depending on the driving mode you select. You don't get the little rear seats you'd get in the Coupe version, but BMW has carved out 100-litres of storage space behind the front seats in compensation. Which is just as well because the boot you get out-back is only 84-litres in size.
Market and Model
BMW expects this open-topped i8 model to outsell its fixed-top stablemate at a rate of three to one, despite the fact that this car comes at quite a premium in its Roadster guise. At the time of this test, in Spring 2019, the £127,000 asking price represented a £12,000 premium over the Coupe model. It now seems a long time since the 2014 i8 launch when, with the aid of a government grant that's no longer offered, the Coupe version of this model could be yours for nearly dead-on £100,000. Both body styles come in a single plug-in petrol-electric hybrid specification and one auto-only 6-speed paddleshift gearbox.
Standard equipment includes Adaptive LED headlights and gorgeous 20-inch 'W-spoke'-style 470-series light alloy wheels. The retractable soft top roof and the innovative Dihedral doors will doubtless be car park talking points too, while those who look a bit closer will note the high gloss black blue-accented brake callipers. Metallic paint is standard and the main i8 exterior colour choices - pearl-effect 'Crystal White', 'E-Copper', 'Donnington Grey' or, as in this case, 'Sophisto Grey' - all come with contrasting colour panels in areas like the bonnet. And 'Frozen Grey' metallic accent surfaces on the side skirts, at the rear and on the front kidney grille surround.
Inside, there's leather not only for the grippy heated electric sports seats but also for the dash binnacle, as part of what BMW calls its 'Carpo' 'interior world' package. Plus you get the brand's 'Carbon Fibre Interior Trim' package, which uses that finishing for the dashboard inlay, the centre console and the door handles.
Cost of Ownership
Revisions to the i8 have delivered a more densely-packed version of the original model's lithium-ion battery, which offers greater capacity (raised from 20 to 34Ah) and uses fourth-generation cells that increase energy output from 7.1 to 11.6kWh. As a result, this car's all-electric driving range has been increased by nearly 50% - it's WLTP-rated at 32 miles in the case of this Roadster variant. That's providing the battery's fully charged, a process which takes just under three hours when the car's plugged into the BMW i Wallbox that if you own this model, you'll want to install in your oak-framed garage. Electrical assistance does wonders for efficiency of course. The unrealistic quoted WLTP fuel figure is 128.4mpg on the combined cycle and there's an NEDC2-rated 46g/km of CO2 reading that equates to a Benefit-in-Kind taxation rate of just 13%.
Of course, you'll also need to take into account the cost of the electricity you'll be using to power that uprated battery. Your electricity costs will obviously vary, depending on your supplier and when and where you choose to charge, but as a rough guide, by our calculations, 100 miles of full EV motoring in this car would probably set you back around £8 in electricity charges.
Like its coupe counterpart, this i8 Roadster offers a fundamentally different interpretation of what a super sports car can be. At the wheel of one of these, high performance motoring is no longer an ecological embarrassment but an expression of futuristic fascination. In an i8, more than any other car of its kind, driving enjoyment and planet-friendly performance at last meet in unison. It's a very special blend and in Roadster form, a beautiful piece of pavement theatre.
Hybrid power may ultimately be the wrong direction for all our automotive futures, but like it or not, we're going there, so let's have some fun on the way. The i8 brings us that - particularly in this Roadster form - and delivers much more besides. Nothing else we can think of in this segment is so striking, surprising and sensational, yet so ultimately sensible in what it sets out to offer. It's a landmark car: nothing more, nothing less. And an incredible achievement.