Car review: BMW i8 hybrid - can a real sports car be eco-friendly?

BMW says its hybrid i8 will heralds a new era of sports cars. It claims to rival a Porsche 911 for performance with the fuel economy of a Toyota Prius. But is it ultimately any good?

The entire world of sports car makers is pinning its hopes on the i8, and not just BMW. It can run as an electric car, as a fuel-saving plug-in hybrid or as a sports car pumping both electric and three-cylinder, turbocharged petrol power to its wheels. It drapes concept-car-for-the-road skin over a four-seat carbon-fibre chassis and it even introduces laser-fired headlights to the world. It's supposed to be an eco-friendly Porsche 911 hunter and is priced to match. Can it really do all of that in one car?

There is a lot riding on the i8, and not just for BMW. More than anything else, it’s an attempt to convince the world’s naysayers that even something as selfish as a sports car has a future, without the loss of any of the fun stuff, if the genre steps up to its social responsibilities.

It’s BMW’s supercar; super for its technology even more than its 4.4-second sprint to 100km/h. It takes the i3’s lessons and tacks 911 speed and eye-magnet style onto it. It features laser headlights with high beam clarity at up to 600 metres. It delivers better economy than a Prius, so you can be sexy and fast without feeling guilty.

Its combinations are, by now, well known: a four-seat, carbon-fibre tub atop an aluminium chassis (very much like the i3), plus a five-link rear suspension. A 96kW electric motor up front and a thumper, 170kW version of the MINI Cooper’s 1.5-litre three cylnder down the back. A 7.1kW/hour lithium-ion battery pack stuffed into the transmission tunnel and wire-frying brainpower. Electrical regeneration on the go via the front electric motor and the option of simply plugging it into the wall.


And it’s supposed to do all of that and still deliver a cracking drive that will pull even passionate Porsche drivers out of their 911s and Cayman S models, all while shrinking their running costs with a combined fuel economy number of only 2.1 litres/100km.

It is supposed to be a pure sports car drive at anywhere between a third and a half of the fuel consumption, along with the ability to commute emissions-free for most people. How can that go wrong?

Well, complexity, for one thing. Electronics and software complexity, to be more specific, because the rest of it is surprisingly (in this day and age) conventional.

The engine is a modified version of the MINI’s three-cylinder engine, with more power and more torque. It has variable valve timing and lift, 320Nm of torque (not bad from 1.5 litres) and a big artificial system to help it sound like a sports car. A bit.

BMW chose this because it’s a light engine, but it also chose it because it was one less thing to develop from scratch. Another thing not developed from scratch is the gearbox, because it’s a modified version of the MINI Cooper’s six-speed Aisin automatic. You can almost think of it as a front-drive layout, turned around and plonked in the back, driving the back wheels.

In fact, the petrol powertrain only gets complicated because it needs to turn the back wheels in harmony with what the electric motor is doing with the front ones, plus what the cornering demands are and what traction the tyres can use. Electric motors spin up more or less instantly, but petrol engines need time to pick up their revs. BMW overcomes this by fitting the three-pot with a belt-driven, 11kW electric motor to it to speed up the crankshaft’s acceleration and it also acts as its starter motor when it the engine is chiming in and out during hybrid work.

The electric synchronous motor delivers 96kW of power and, from a standing start, an immediate 250Nm of torque and it delivers it all to the front wheels exclusively. It does that via a two-speed automatic transmission of its own.

That’s the nuts and bolts of what is a very complex system, but there’s a lot more to it than just that.

For starters, there is an electric mode, which runs the car as a pure electric vehicle to allow you to plug it in at home or work, then drive it for 37km (on the NEDC numbers) without paying for fuel. Only in electric mode does the car actually use the two-speed auto’s first gear, because the 96kW motor is moving the 1,485kg car all by itself and needs a bit of help.

Then there’s a Comfort mode, which runs the car as a hybrid, with the petrol motor (or ICE - Internal Combustion Engine - as BMW calls it) chiming in and out as the computers see fit. Sometimes it’s churning more grunt to the rear wheels, sometimes it’s off.

It’s all hands on deck in Sport mode, even though there’s no button for it. You just move the gearlever across into the sequential gearshift plane and go for it, with both the ICE motor giving its all and the electric motor punching hard, too. As a bonus, this also lifts the threshold of the stability control systems, delivers quicker shifts, more noise and also stiffens up the suspension.

This is all well and good, but where does it stand against its key rival, the 911? Given its all-wheel drive status when it’s going hard, it’s probably a direct rival only for the 911 Carrera 4 or 4S. It’s heavier than both of them (the Carrera 4 is 35kg lighter and the 4S is 20kg lighter), but then it does run two motors instead of one, and has a very big battery pack.

It’s also just a tenth slower than the 294kW Carrera 4S to 100km/h and from 80-120km/h, so it’s in the ballpark, at least until its limiter arrives at 250km/h.

And then there’s the bit where it smashes the 911 out of the park. Drama. Its shape draws a direct link to the 2009 Vision concept and it’s remained faithful to it. It doesn’t have the see-through doors, but they still lift up gullwing style in one piece to give access to the front and (like the 911) tiny rear seats.

It’s gorgeous and it’s just about the only thing on the road today that looks like a concept car. Which it kind of is.

Sadly, while most of the driving parts of the i8 work very well, it falls short in several critical areas. It’s as though it has arrived with six months of development left in the software that controls what shuffles backwards and forwards, though BMW insists it’s right on time.

There is much to love, though, which is what makes the i8 at once absorbing, mesmerizing, delicious, frustrating and infuriating, in almost equal measure.

You sit very low in the chassis and the car’s centre of gravity is also lower than normal, thanks to the electric motor, the heavy battery pack and the ICE engine all tucked away near the floor. You sit in a cabin that is gorgeous, with far more luxury materials on offer than in the i3.

There is dual-zone climate control (also subject to the big brain when it’s in electric mode), there are electric seats, there is cruise control (though not radar cruise) and a big, permanently raised multimedia screen, plus TFT digital dashboard with a cool overarching shade.

There are, though, no door pockets (everything would fall out when the doors opened), one small, shallow cupholder at about elbow level, plus two in the rear seat for the thirsty halflings that could comfortably sit there. There is little rear headroom, less legroom and, like the 911, it will be adequate for short journeys but more useful as the real-world luggage area.

The German media complained that the car rode too firmly in Comfort mode, but we didn’t find that. It might be firm and lacking the suppleness the best 911s use to ooze their way through the rough stuff, but it worked pretty well. You feel what’s under you without being too heavily jolted and the lateral body control, in particular, is superb. There is no head toss and it corners very flat, regardless of the speed.

It’s also quiet, with the exception of some rear tyre noise, and the electric motor is surprisingly powerful, even when it’s operating in isolation. It’s strong enough that it runs its first gear to 120km/h before switching to the big gear and it’s easily swift enough to flit its way through traffic without bothering the petrol tank. In short, it’s an impressive electric car.

It’s a good hybrid, but not a great one. There are times when the petrol engine power doesn’t arrive with the seamlessness you’d hope for. Most of the time, though, it’s pretty good and very efficient. And quiet. The three-cylinder can be a quiet thing, as proven in the MINI, but it’s particularly quiet here, except when you poke it with the stick that is the Sport mode.

Flick the lever across and the sound changes instantly into a deep, rumbling hum that isn’t anything like a classical sports car engine and, from the outside, sounds more like a big, thumper diesel six.

The car is more lively, in an instant. It launches away from rest with terrific security and you can hear the electric gubbins fizzing beneath the artificial overtones of the three-cylinder engine.

And it’s quick. Very quick. When both the motors are punching hard, so does the i8. It’s maybe not 911 quick over the first 20 metres, but it seems like it covers ground on the legendary rival after that. And at higher speeds, above 150km/h, the slippery shape helps the i8 accelerate like it’s not fading away at all.

Then there’s the handling. All that low weight means it’s a slingshot jet in faster corners, stretching the bounds of credulity as it flits between high-speed sweepers and bends. It’s delightful, even if the accurate steering could use some feedback instead of feeling a bit like a gaming console.

If it’s tackling the road in third gear or higher, it has brilliant throttle response, with the electric motor arriving first (just) and the rear motor helping an instant later. Its flat cornering helps, too, and the rear end never feels like it will bite, even over the bumpiest roads with the most ham-fisted moves. It’s excellent stuff when the pressure is on over fast roads, which makes the low-speed quirks so damned irksome.

If the i8 is attacking bends in second gear (or having to downshift to second regularly), it’s nothing like as convincing a machine as it is when the going is faster.

Initially, that’s because the gearbox is inconsistent on its downshifts. It’s probably the cheapest part of the car and feels it. There were times when it wouldn’t respond to the downshift paddle, even though it was labouring the engine at 3,000rpm, then at other times it would merrily downshift at 4,500rpm to get to the same (second) gear.

It also doesn’t have a proper manual mode, with the car auto upshifting at the limiter and maintaining a détente kickdown, regardless of how obviously you were tapping paddles.

Then there’s the initial turn in. Its front tyres are like toothpicks compared to the rest of the sports car world (195/50 R20) and they’re also geared up for efficiency. And, if you arrive at a corner from a straight piece of road and try tipping it in at anything like a normal 911 pace, you’ll find yourself battling significant understeer while the rubber squeals constantly.

It’s odd, because the car will change direction impressively if there is any lateral load on the suspension, like going from one corner to another, but it’s singularly unimpressive moving from a straight line.

Coupled to that is an overly busy-body ESP (the car is way better when you switch it off and the chassis is so calmly organised that the i8 won’t bite) and very lazy response when you’ve finally got the nose turned in to a corner and you try to pick up the throttle.

And when the drive does come in, it feels like the delay has been caused by the electric motor up front waiting for the petrol engine delivery to reach its levels. And then the car gets torque steer from the electric motor on the way out. And there doesn’t feel like there is any torque vectoring at all, which is one of the supposed benefits of electric performance cars.

To be fair on the i8, it has been a rushed and incredibly complex development period and there is still more to come from the software - and most of our issues felt software related (gearbox apart). But it’s still nothing like as intuitive to drive across the board as a 911, even though it’s a diamond in faster bends.

BMW says they are still developing the car and it felt demonstrably worse in second-gear than it does when it gets going properly, but its second-gear issues are significant.

Early adopters will love it, and the convenience of its fuel range in town will sway plenty of people - especially those who don’t explore the handling beyond 8/10ths, but it’s a good car with some serious issues. And it’s frustratingly close to being great.

While we wouldn’t write it off yet, it’s a pity because it’s so significant that we were really trying to love it. Instead, we just like it.

Lowdow: BMW i8

Engine: 1.5-litre in-line, turbocharged three, two electric motors

Output: 266kW/400Nm

Transmission: six-speed automatic, two-speed automatic (electric)

Fuel: 2.1L/100km (combined, auto)

CO2: 48g/km (combined, auto)

0-100km/h: 4.4 seconds

What we liked:

- Terrific high-speed cornering ability

- Astonishing looks

- Prius-beating economy

Not so much:

- Low speed understeer

- Poor initial second-gear throttle response

- Hybrid drive transitions aren’t perfect