BMW complements its electric i3 with this petrol-electric range-extending version of its brilliant new 'premium' urban vehicle

What is it?

Nearly all car enthusiasts will, by now, be familiar with the radical BMW BMW i3. Announced as the ‘Mega City Vehicle’ just over three years ago, the electrically driven production version is finally on sale in the UK. 

Based on a separate aluminium chassis, topped with a carbonfibre reinforced plastic bodyshell, the i3’s rear wheels are driven by a rear-mounted electric motor, good for a peak power output of 167bhp and 184lb ft of torque from standstill.

This model is the i3 Range Extender, which gets a two-cylinder petrol engine/generator to act as back up to the 18.8kWh lithium-ion battery. The two-cylinder, 647cc engine - adapted from a BMW scooter - is made in Korea to BMW’s specifications and develops 36bhp and 40lb ft of torque at around 4500rpm, which seems to be the speed that the engine is programmed to run at when it is called into use. 

Described as being ‘sealed in a box’ under the rear boot floor (although it sits alongside the electric motor), the petrol engine (which already meets strict EU6 pollution regulations) cannot mechanically assist by driving the rear wheels. This is in contrast to the Chevrolet Volt, whose range-extender engine can actually ‘clutch on’ to the transmission. 

The i3’s tiny engine/generator gets an equally tiny nine-litre fuel tank and what one BMW employee told me was a “real-world economy of between 40 and 50mpg” when driving the i3 purely on the engine alone. Officially, this car is rated at 470.8mpg.

On paper, there are downsides with the addition of the range-extender engine. Weight rises from the 1195kg of the pure EV i3 to 1315kg. This very slightly blunts performance, with this version of the i3 having its 0-62mph sprint time increased from 7.2sec to 7.9sec, while the crucial urban 0-37mph time is eased back from 3.7 to 3.9sec.

What's it like?

Despite being unlike any previous BMW production car, the i3 has plenty of this brand’s best characteristics. The i3 has beautifully weighted steering, a first rate drivetrain, sparkling open road performance and remarkably assured handling for a short, tall car.

The styling is either alarmingly modern, or just plain over-done, depending on your point of view; but I doubt few people will have a problem with the interior. The cabin is remarkably modern: the huge view forward, the undeniable effectiveness of the twin-screen dashboard and the journey-enhancing airiness for front seat passengers. Top marks, also, for the quality, detailing and logic of the switchgear.

In heavy traffic, the i3 has remarkable off-the-line pace and can be positioned with a directness that leaves most other traffic stumbling. The driver can exploit openings in the traffic flow with a speed of reaction than even the Nissan Leaf can't match; and the i3’s semi-high-rise driving position is also a particular advantage in town, as is the 9.8m turning circle - something beaten only by a London Black Cab.

It is also surprising how well the i3 copes with the cratered streets of London on this test drive, feeling taughtly sprung and yet not crashing across broken surfaces. BMW’s chassis teams now carry out testing in the UK and it is clearly paying off.

On quicker A-roads, the i3 has a very impressive pace under full acceleration. Long uphills are demolished in fine style, with a seamless stream of torque (thank the combination of an electric motor and a single-speed transmission). The i3 also has remarkable stability, as a series of driving exercises at Brands Hatch prove. Sharp lane changes and even a stretch of hilly circuit in the pouring rain fail to ruffle the i3, even though it has 155/70 tyres at the front and 175/70s at the rear.

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On the return leg to central London, the range extender activates, allowing it to cut in and out as required by the conditions. It is just about possible to hear it running – the sound is of a very distant thrum – and then probably only because the cabin of the i3 is so very quiet. The i3 also has pre-set levels of regenerative braking. It’s quite an aggressive setting that slows the car quickly once the driver lifts off the accelerator.

In terms of low-pollution fossil fuel running, the use of this small petrol engine is a masterstroke with, for example, emissions of unpleasant NoX gas at just 0.0009 g/km. You have to wonder whether the electricity created by the i3’s range extender is ‘greener’ than what the average power station can manage. With a full battery and fuel tank of fuel, BMW predicts a real-world range of between 150 and 186 miles and claims CO2 emissions of 13g/km.

There are downsides to the i3. After the price (although the standard spec in ‘Standard’ trim is pretty comprehensive), the main one is probably the restricted space in the back (and tight boot) and the fact that the rear suicide doors cannot be opened without the front door being opened first. Many will find this problematic on the school run. The tiny fuel tank means that long journeys will mean refueling as often as every 80 miles. Otherwise front seats are also rather flat and need bolsters considering the i3’s handling abilities.

Should I buy one?

Buying a car like this is a very individual choice. Assuming you have the ability to charge the i3, there’s no doubt it is the sharpest handling, quickest and most premium-feeling EV on the market, if not the most capacious or family friendly.

The addition of the tiny range extender is a masterstroke (although it adds £3150 to the price), although the tiny fuel tank a serious frustration. Even so, despite being different in every possible way, the i3 is recognisably a real BMW.

BMW i3 range extender Standard

Price £33,830 (before £5000 government grant); Top speed 93mph; 0-62mph 7.9sec; Economy 470.8mpg (Combined); CO2 13g/km; Engine 2 cyls petrol 647cc, petrol with integrated generator; Power 36bhp at 4500rpm; Torque 40lb ft at 4800rpm; Electric motor power 167bhp peak; Torque 184lb ft from start; Gearbox single speed

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Join the debate

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alexanderkemp 7 December 2013

Ive Driven one

I was fortunate to drive an i3 but without the range extender this week. and it was awesome. Personally I like the styling and the interior was also really impressive: simple and stylish. I couldn't believe how quick the thing is! There is barely anything on the road that can keep up with it up to 60mph. I could certainly foresee having one of these as a town car.
Motormouths 8 December 2013

alexanderkemp wrote: There is

alexanderkemp wrote:
There is barely anything on the road that can keep up with it up to 60mph.
I think you're getting a bit ahead of yourself there! :-)
alexanderkemp 10 December 2013

I mean that in terms of

I mean that in terms of driving in a realistic town environment. if you see a gap you just hit the accelorator and it goes. There is no need to change gear or wait for the auto box. It is instant and effortless. That is what I was trying to convey. Prehaps the feeling is hightend by it being quite narrow and easy to position.
Motormouths 10 December 2013

alexanderkemp wrote: I mean

alexanderkemp wrote:
I mean that in terms of driving in a realistic town environment.
I hope you're not driving up to 60mph in a "realistic town environment". :-p
alexanderkemp wrote:
if you see a gap you just hit the accelorator and it goes. There is no need to change gear or wait for the auto box. It is instant and effortless. That is what I was trying to convey.
I know exactly what you mean. I'm yet to drive an EV, but I've driven hybrids, and the instant throttle response and lack of let-up from the electric motor can make accelerating at low speeds very quick, quiet and effortless indeed. So much so in fact that it can be difficult to notice how fast you're going until you glance down at the speedo! That said, I think they feel faster than they are. The lack of drama gives the impression that the increase in speed is more effortless than it actually is.
Cardor 8 November 2013

Rex cruising power?

I'd be interested to know if the i3 is able to operate at full power when relying solely on the rex to charge it's battery. For example, could it maintain a 70mph cruise with it's battery drained? I appreciate the motorway isn't it's natural home but I could see myself using this as my only car for commuting to central London and for the odd trip to Birmingham a couple or so times a year. But this would only work if it could maintain a motorway cruise on petrol generated power. Somehow I doubt the 36hp engine could produce enough power.
Merod 8 November 2013

Issues for me

1. It does not look like a BMW, it looks ..... clunky. Sorry, just being honest (with my need that it looks like the brand that I'm buying into - otherwise you may as we'll buy a volt) Why can't they make these alternative drive train cars look like traditional drive train cars? 2. Two seats on the second row. Come ON! My children do have friends. 3. Those doors? WTF? Thus would be a second car, thus a school run car. Those doors will not make for a practical drop off. 4. Boot. School bags. School sports bags. Musical instruments. Times two.