A ride in BMW’s cars of the future

It's still almost a year before anyone can to buy one, but Top Gear has been poking its nose into the arctic testing of BMW's radical i cars. We've had a ride with the engineers on roads and a frozen lake. And? They really do feel like machines from the next generation.

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The BMW i8

The BMW i8 is the cleverest sports car… in the world. It's not just about a new petrol-electric 4WD system. It uses new materials, fresh aerodynamics and a new approach to tyres and chassis. And on the road it can keep up with a M3 or 911 Carrera, using only half the fuel as it goes.

But it still feels and sounds like a sports car, not a strangely whirring hybrid. And if you don't have any Porsches to chase, you can pootle across town to get to work, running entirely electrically and using no fuel whatever.

Up at BMW's winter testing ground, there's a big patch of electrically warmed tarmac. So you're on a dry grippy surface where all around is snow and ice. We arrived at one end of it. My engineer stopped, put the car in sport mode – which both starts the petrol engine and tells the additional electric motor to contribute its best efforts too. “Ready?” he asks. Why need he ask? Because when he pressed the loud pedal I really did have to be braced. It properly kicks you in the back.

So, on first impressions I don't for one minute doubt BMW's claim of 4.6 seconds for 0-62mph. And because the body is designed to be so slippery through the air to aid economy, the 155mph governed max should be a cinch too.

Then we go off to the snow tracks. There's a circle hundreds of metres across. My man negotiates this in one constant opposite-lock drift. Then we do the snakier track, and again it's obvious the car has loads of traction, but it's definitely rear-biased. The car isn't so much cornering as moon-walking.

It has been an immense task to make the engine and electric motor and stability systems talk to each other sweetly enough to let the car feel natural and smooth in these sliding transitions. We won't really know until we've driven it whether it fully works out on tarmac, but so far the signs are good.

Then we go out of the track onto a twisty bumpy back-road, where it's possible to feel how rigid the body is, and how it rides like a real sports car. It's taut but not harsh, and your body isn't thrown around because you sit low down between the wheels.

We also spent a while mooching through a little town in electric mode. Very smooth and stealthy. Well, as stealthy as you can be in a UFO-shaped car that's covered in bright blue swirls.

If you love engineering as well as driving, this will all get your hormones throbbing. But there's more to the BMW i8 than that. It's a lovely visual object. It resides in a set of clothes that are as new-age as the technology, a set of highly sculptural yet functional forms.

It's was covered in squirly disguise today, and these prototypes have temporary head and tail-lights, so the pictures don't tell the full story. But luckily, BMW has issued a couple of concept cars lately that show just what it'll be like.

The i8 Concept above shows almost exactly the 2+2 layout and the swoopy exterior, with two layered side panels forming 'air curtains', and those wonderful detached spoilers over the rear pillars. The only significant departure from production is the glazed bottom half to the upward-swinging doors.

Meanwhile the i8 Spyder Concept above demonstrates the final interior. Lovely, innit? Very modern and very unlike the usual aggressive sports-car cliches.

The i8's 2+2 body is a carbonfibre tub. Behind the driver is a highly turbocharged 1.5-litre three-cylinder petrol engine making 220bhp (next year it'll be in a Mini Cooper S). At the front is an electric motor chipping in another 129bhp. So you've got rear-biased four-wheel drive with instantly variable torque split. The centre tunnel of the car holds a battery stack, so the car can run as an efficient hybrid when you don't need full performance, or as a plug-in hybrid to give a 20-mile electric range.

The petrol engine runs through a six-speed paddle-shifted sequential transmission (again adapted from Mini), and in the sport mode it runs full-time. That's why you get such a natural impression of speed, and a real engine noise. At the moment the noise is a bit like that other turbo triple, a Smart. But they are about to add an active exhaust system to make it fruitier, as well as an electronic noise modification system through the hi-fi-speakers.

The official cycle economy figure is 104mpg. But this includes some electric range which doesn't count towards the 66g/km CO2 figure. The engineers admit that this makes it unrealistic, but they say it should do 40-50mpg even when you're pressing on.

Why? Because it's designed to be a great drive on the roads, not at tracks. It won't keep up with an M3 lap after lap, because that would run down the battery. But they swear there's hardly a road where the regenerative braking of the hybrid system wouldn't be enough to keep the battery charge up. So it would always be ready to give the e-motor the full beans when your floor it.

By the same token, a maximum speed over 155mph would deplete the battery, but at a steady, limited 155 then the petrol engine can do all the work and the battery doesn't deplete.

And by designing for a 155 max, they can keep the tyres thin, the brakes small, the cooling system compact and light, the aerodynamics optimised for drag rather than ultra-high-speed downforce. That means the car is performing better and more economically at real-world speeds, rather than being compromised for unreal speeds.

The i8 goes on sale in spring 2014 and will cost about £100,000. 

Like the BMW i8 but not the £100k price? But there's one way to get quite a lot of its technology in a car about a third of that money. And it'll seat four people.

That's the i3. This is the pure-electric member of the family. But if that scares you, remember there's the option of a little range-extender petrol engine to turn it into a full long-distance machine. But today we're in the pure electric version.

Again it looks a bit boxy and sad in its disguise, but check out the recent i3 Coupe concept to see how the tail and nose and interior will actually look. The real i3 has ‘clap-hands’ doors to get you into a surprisingly large rear seat. There's as much room in this little box as a three-series. And it really is a gorgeous interior design, all light surfaces and space and tasteful minimalism.

Because you sit so high, you think it's going to feel like a crossover or MPV, all nautical and rock'n'roll. But it doesn't. There's little roll or pitch and it's clearly very agile. If it slides under power, it slides at the back.

The reason is that all the heavy bits are right down near the ground. In an x-ray, the mechanical bits of the i3 look like a skateboard: there's a flat aluminium frame that cradles everything. At the back is the electric motor and high-voltage electronics, then the rear suspension (it's rear-drive), then under the people is the square sandwich-shaped battery, then the front suspension and a radiator to cool the electronics. Then the people sit in a separate module bolted to the top, a solid carbonfibre frame.

It's not slow, either. It uses the same motor as the i8's front motor, but rated up to 168bhp, driving a weight of just 1250kg. That means 0-62 in 7.9 sec. Riding in it, the over-riding impression is of quiet authoritative surge.

The carbonfibre is key to these cars. To drive a heavy steel body needs a lot of battery. And battery itself is heavy, so to an extent the extra battery is self-cancelling and yet its punishingly expensive. The i3 has a relatively small battery and yet its range – 140 miles in the official cycle, "80 to 100 miles" real-world – is about 30 percent more than a Nissan Leaf's. By developing revolutionary new processes and using cheap hydro electricity for the process, BMW has greatly reduced the cost of carbonfibre, and found ways to build it quickly.

So the BMW i3 sounds like an exotic car, but actually it'll be cheaper than you'd expect. Perhaps not much more than a Leaf. We'll know when it goes on sale in the autumn…