BMW’s i8 Roadster: how to be gorgeous and still care for the environment

The thing is that there really isn’t anything else, at least not yet. If you want to have a low-slung, sexy, slinky, agile, fun-to-drive sports car but you have a nagging environmental conscience and therefore want to have a hybrid, or better yet a plugin hybrid, then there is no current other port of call.

There's the Lexus LC500h hybrid but that's more GT than sports car, and there's no convertible (yet). Porsche hasn't yet created a hybrid 911 (though it will, in due course) and neither has Ford yet unleashed a hybrid Mustang (thought ditto and indeed likewise), so for now the BMW i8 Roadster sits alone, standing out all in a field by its lonesome.

The i8 coupe we’re, I guess, well enough familiar with by now. Hip-high wedge shape, Blade Runner styling, Lamborghini-impersonator doors, mostly-carbon construction (exotic, light, strong), and a plugin hybrid powertrain that combines a testosterone’d Mini Cooper 1.5 turbo triple engine and electric motor for M2 Coupe acceleration. All of that with claimed emissions and consumption figures so eco-friendly that they probably grow their own organic lemongrass.

For the Roadster, take all of the above, add one tin-opener, and subtract one roof. A simple recipe? Not quite. BMW is not a company known for doing things by halves (unless you count timing chains but here is not the arena for such a discussion). Actually, the i8 Roadster has some distinct, if detailed, differences to the Coupe.

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For a start, the doors a different. They still open butterfly-style in an unbeatable bit of street theatre (unbeatable, until the sweaty, wheezing mid-40s motoring writer tumbles out of them) but now they’re frameless. The exterior skin is also different, to allow the side glass to sit at a slightly more acute angle, which makes for a better seal with the convertible roof when it’s up.

Carbon-fibre build

You’ll also notice a lack of rear seats, their space now taken by the roof mechanism, and a small, but useful, extra bit of luggage stowage behind the two remaining seats. The roof mechanism, which can fold the simple soft-top away in just 15 seconds, adds an extra 60kg to the car (and includes incredibly intricate 3D-printed alloy structures), which isn’t bad, but perhaps rather flies in the face of the Coupe’s lightness-is-everything carbon-fibre build. That carbon core structure remains, modified to provide roll-over protection in the event of a truly horrendous accident.

The powertrain was also given a going-over. The battery for the electric part of the system sees its power and outputs raised to 34Ah and 11.6kWh. That increase means BMW can run the figures on the i8 Roadster according to the tougher new WLTP economy and emissions test, and still retain the old 50km range for electric-only driving.

The electric motor (which actually powers the front wheels) has also been given a boost of 12hp, bringing it to 143hp. Combined with the 231hp 1.5-litre three-cylinder turbo engine (which powers the rear wheels) you’ve got 374hp, a small increase which actually drops the 0-100km/h time to 4.6secs (or 4.4secs for the lighter Coupe, which also gets the new motor and better batteries).

BMW claims (scepticism at the ready…) 2.0 litres per 100km fuel economy (I’ll save you the bother – that’s 141mpg) and 46g/km of Co2 emissions. Which for any car would be remarkable, but for a sports car is into the realms of the implausible.

You won’t get 141mpg, of course. In fact, over a day’s hard (occasionally soft) driving across the mountains of Majorca, the i8 Roadster averaged 8.8 litres per 100km, or 32mpg. That’s not enough for a bishopric, let alone sainthood, but by the standards of other carbon-bodied, mid-engined sports cars (McLaren 540S, LaFerrari) it’s better than decent. Plus, you can schlep around town on silent, emissions-free electric power, which is good for the soul, and also good for scaring witless pedestrians.

While the i8 plays the roadster-sports-car visual game perfectly, it’s not quite perfect to drive. The styling sucks you in with its dramatic futurism, but you can’t beat the laws of physics, and the i8 Roadster is dealing with the weight of a battery pack, plus the extra unwelcome 60kg for the roof, all of which is mounted up high, where you want it least.

Agile and responsive

Which means that the i8 flatters to deceive a little. Initially, it feels agile and responsive, but on a truly challenging road you soon run into the limitations of its narrow tyres (kept deliberately skinny for better aerodynamics) and the Roadster can need some careful choices of braking points and cornering lines if you're to get the best out of it. On the narrow, twisting roads above Palma, it would be undone by a Porsche Boxster GTS (or even a good hot hatch, come to that).

No, the i8’s pleasures are best experienced on more open, sweeping roads, where you can thoroughly exploit the prodigious torque of the combined electric and petrol power, and the steering (which feels good but doesn’t offer much actual, real feel) becomes less of an issue when you’re not asking it to rush. It sounds brilliant too – BMW has actually added an exterior-facing speaker for the engine’s artificial sound system, so that passers-by can also appreciate the (largely convincing) faux-V8 soundtrack.

It’s always going to be something of a carbon-fibre trinket (BMW Ireland expects to sell just four of them in a full year) but it is one with serious intent. This really is the future, or at least a variation on a future theme. A car that can (largely) thrill, visually excite, and even give you a dose of the aural tingles, yet all shot through with a genuine environmental conscience, and a million miles of headroom. For now, there’s nothing else like it.

The lowdown: BMW i8 Roadster

Price: €171,390 as tested.

Power: 374hp.

Torque: 320Nm (engine); 250Nm (electric motor).

0-100km/h: 4.6sec.

Top speed: 250km/h.

Claimed economy: 141mpg (2.0 litres/100km).

CO2 emissions: 49g/km.

Motor tax: €170.

Verdict: Wonderful both to look at and boast of, but not as sharp to drive as some rivals. Assuming it has any rivals. 4/5