| Published
on 1
Nov 2013 |
All rights reserved.
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Nissan Leaf, Tesla
Model S, Renault Twizy, Zoe and Fluence Z.E., Chevrolet Spark EV, Fiat
500e, Mercedes SLS Electric Drive… there are more and more electric
vehicles on the market now, but I think none of them is as
revolutionary as this BMW i3. The i3 project, internally known as
"Megacity", is a big gamble on EV as well as carbon-fiber technology.
It is not just another high-tech showcase like SLS ED or Volkswagen
XL1, but a volume model destined to the garages of middle class. BMW
reportedly invested some 2 billion euros into this project, and a new
production line with annual capacity of 40,000 units has been set up at
the Leipzig plant. If it succeeds, it will open up opportunity for a
full range of i-cars, fueling BMW with a new (and potentially
substantial) stream of new customers. Even if it fails, the EV and
carbon-fiber technology it learnt will benefit other BMW models to come
in the future.
The brave new marketing of i3 is key to its success. How to sell a car
of the size of Ford Fiesta at 2 to 3 times the price? Answer: it has to
be very desirable. The green and lightweight technology it used (more
on that later) is one reason, equally important is to give it a
space-age look and premium quality feel. You think a Renault Zoe look
futuristic? Turn to the i3 and you will find the Renault hopelessly
conventional. You think the interior of Tesla Model S classy? The BMW
compact trumps it easily with Scandinavian-style design and materials.
It also uses many recycled and eco-friendly materials to match the
green credential of EV. IT addicts will love its simplicity and feel
comfortable with its standalone LCD screens. It is designed for new-age
people.
It could be difficult to classify the i3. Price-wise, it is about the
same as a 328i. Even with government incentives taken into account
(for example, £5,000 in the UK and $10,000 in California),
it still costs the money of a low-end 3-Series. Size-wise, it sits on
the borderline between B and C-segment. Its 4-meter length is very
compact, but it is pretty wide at 1775 mm and unusually tall at 1578
mm. This tallness is due to the fact that the battery is located
underneath the floor, like most other EVs.
Its chassis is revolutionary. You think Alfa Romeo brave to introduce
carbon-fiber chassis to its £45,000 4C? The i3 pushes the entry
price down to the level of £30,000, even with a big pack of
lithium battery included! Like-wise, its production volume makes it the
first truly mass production carbon-fiber car. BMW thought hard how to
make it commercially viable. The i3 does not use conventional
construction. Its chassis consists of 2 parts: a passenger cell made of
carbon-fiber reinforced plastic (called "Life module") houses the cabin and
provides passenger protection, while an aluminum-frame lower chassis
(called "Drive module") carries
all the mechanical and electrical components, including the battery,
motor,
suspensions and the crash structures. The last one is very important,
as it keeps the expensive CFRP passenger cell free of light collisions
and saves repair costs. Outside, all body panels bar the roof are made
of injection molded glass-fiber reinforced plastic. They can be easily
detached and replaced in case of damage, again saving repair costs. The
roof is made of recycled CFRP.
To make possible mass production, the production process of i3 is
highly automated. Carbon-fiber materials supplied by SGL (in which BMW
holds minority stakes) are shipped to Germany where they are turned to
laminates and then shaped to individual parts. The Live module consists
of 150 such parts. In Leipzig they are bonded together by adhesive
using robot arms. BMW developed new techniques to shorten the hardening
time greatly, speeding up the assembly. Meanwhile, the aluminum Drive
module is assembled at another production line running in parallel to
the Live module. They are then bonded and bolted together by robots.
Finally, the outer skins are put in place, again by robots. The whole
assembly process takes only 20 hours.
Thanks to the state of the art construction, the i3 tips the scale at
only 1195 kg, even though the battery alone weighs some 230 kg. It
undercuts a Chevrolet Spark EV by 160 kg and Nissan Leaf by a massive
330 kg! It goes without saying that the reduced weight helps boosting
performance and mileage. It also means the i3 can use a slightly
smaller lithium-ion battery (22 kWh, vs 24 kWh on Nissan Leaf and Fiat
500e) to partly offset the cost of its carbon-fiber/aluminum chassis.
BMW quoted a class-leading range of 80-100 miles and a remarkable 0-60
mph time of 6.8 seconds. That's the territory of hot hatches, although
top speed is limited to 93 mph to save the battery. The electric
motor's remarkable output of 170 hp and 184 lbft also helps it to
distinguish from other urban EVs we have seen so far.
To those fearing 80-100 miles range insufficient, they can opt for the
range extender, which is actually a twin-cylinder 650 cc BMW motorcycle
engine. It is mounted next to the electric motor at the rear axle. Its
34 hp output works solely to generate electricity to power the motor
and recharge the battery. This extends the range to 160-186 miles and
allows the car to refuel at gas stations, thus the fear for running out
of energy is no longer a concern. On the downside, it carries a weight
penalty of 120 kilograms thus 0-60 mph is lengthened by 0.7 second.
The i3's rear-engine layout was chosen primarily for packaging
benefits, but interestingly, it keeps the traditional values of BMW
intact, such as rear-wheel drive and 50:50 weight distribution. A
quick, 2.5-turns power steering and suspensions consisting of
MacPherson struts up front and five-link axle at the rear also sound
very BMW indeed. Unusually, the small car employs very large (19-inch)
aluminum wheels but extremely narrow (155/70) tires, which reduce
aerodynamic drag yet
offer decent traction.
Apart from the design, interior, chassis and propulsion system, the i3
also differs from conventional cars in another area: suicide rear
doors. Thanks to the super-stiff carbon-fiber passenger cell, it is
able to ditch B-pillars and make possible for Rolls-Royce-style
rear-hinged doors. This aids access to the rear seats and adds sense of
occasion.
You sit high and upright as in the case of SUVs because the battery is
located right underneath the floor. This gives a commanding view on the
road. Space up front is generous. Not so good at the rear, as legroom
is more Polo than Golf, but the rear bench is wider than a typical
B-segment supermini. The cabin feels light and airy. The rear door
windows are unusually deep by modern standards, thanks to the step cut
into
the waist line, but they are fixed in place. The shallow boot
accommodates only 200 liters but at least you can fold the rear seats
to expand luggage space. The i3 might not be as versatile as
conventional hatchbacks, but as a city car it is more than practical
enough.
So how does it drive on the road? Pretty good. Acceleration is strong,
not only at low speed (as always in the case of most EVs) but also at
motorway
speed up to 60 mph, then it tails off noticeably. The acceleration is
also
delivered seamlessly and quietly as you would expect for an EV. The
regenerative braking is very well tuned so that in most conditions it
doesn't need to trigger the disc brakes. When it does, the brake pedal
feels natural.
Putting the battery and all heavy mechanicals under the floor means a
low center of gravity, thus the i3 feels remarkably agile and stable to
steer. Its small turning circle allows it to be driven and park easily
in urban area. The light and direct steering also helps. However, it is
not exactly a hot hatch. While the skinny tires offer good traction,
they do not produce hot hatch level of lateral grip, thus the car will
understeer early in corners. The suspension setup biases towards the
firm side, so ride quality is marginal. Aural refinement could be
better, as there is a touch too much tire rumble and wind noise
allowed to enter the cabin – perhaps because there is no engine noise
to mask them. However, if you can forget the double-kidney grille – or
if you notice that it is purely cosmetic – and judge the i3 purely as a
green urban compact, you will find its driving dynamics quite
remarkable. Then consider the upmarket styling, interior and
revolutionary technology it employs, you could find it nearly
irresistible.
The only question is price. Is it worth the same as a
conventional 3-Series? If it is my money, I will put on the latter, but
I will enjoy watching my neighbour's i3 and ask him to give me a ride.
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Verdict:  |
Published
on 7
Dec 2017
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All rights reserved.
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i3s
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i3s
offers stronger performance and cornering prowess, but remains a city
car in essence.
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The original BMW i3 had a
lot to amaze, but one thing it didn't quite match the tradition of BMW
is the lack of sporty flavours. This is to be fulfilled by the new
variant i3s. From its appearance, you can already tell that it is
sportier – the wheels have grown to 20-inch, the tires get much wider
and lower profile (175/55 front and 195/50 rear) than the skinny items
on the regular model, and the tracks are widened by 40mm to improve
cornering stability. The suspensions have been stiffened and lowered by
10mm, while the electric power steering is tuned heavier to match.
Outside, you can distinguish it by black wheel arch extensions. The
front bumper is also restyled as part of the facelift applied across
the range after 4 years of service.
Both the facelifted i3 and i3s get the larger 94Ah (33.2kWh) battery as
standard, extending their real-world driving range to about 200km. The
rear-mounted electric motor is beefed up slightly, producing 184 hp
instead of 170 hp, and 199 lbft of torque instead of 184 lbft. This
shortens its 0-60 mph time further to 6.6 seconds, while lifting top
speed slightly to 100 mph.
On the road, the new energy can be felt immediately, although the i3
has always been quite brisk in urban driving. Changes to the chassis is
noticeable, too. It now controls its body roll more tightly, and the
tires deliver much stronger grip in corner. At low-speed maneuvering
this improvement is especially evident. However, up the pace and try to
drive it like a Ford Fiesta ST, its dynamics start fading out. You will
realize that the i3 is still too tall and heavy to be really agile and
composed. Although the center of gravity is low, you sit high thus the
roll angle is evident and confidence-hurting. Wider they might be,
those rubbers still don’t grip as hard as a proper hatchback should,
because they are still too skinny in comparison. Note that the front
tires are narrower than the rears in order to keep oversteer from
happening. You can’t argue with that, because oversteer could be
nervous and even dangerous on a rear-engined car. Anyway, it means the
i3s understeers and lacks adjustability. Meanwhile, the suspension is
stiffened to the extent of borderline firm, lacking the supple quality
of Fiesta, or just any good hot hatches.
Make no mistake, the i3s is not a true hot hatch. Just like a Brabus
Fortwo or Renault Twingo GT, it offers stronger performance and
cornering prowess than its lesser sibling, but it remains a city car in
essence.
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| Verdict: |
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