BMW I3 vs BMW Alpina B4

What's the difference?

Yes, it’s pricey for a small hatch, but this little BMW is a city car like no other. The i3s is tailor made for the urban environment, and six years on retains the quirkiness and charisma that stood it apart at launch, and it can still hold its head high among the current EV crop. 

You could almost call the B4 S the anti-M4. It's still fast and practical but from a completely different perspective. It's much more a grand tourer than the M4 and even with the Akrapovic exhaust (usually a byword for joyous, anti-social racket), subtle.

For some, the price won't matter because the Alpina delivers what they want - M4-like straight line performance without the histrionics or the uncompromising chassis. And there's also a bit of that perverse exclusivity of the styling that you won't get anywhere else.

Built around a carbon-fibre reinforced plastic (CFRP) tub, the i3s is ultra-light (for a battery-electric vehicle), super strong, and unlike anything else on the road.

At just over 4.0m long, close to 1.8m wide, and a fraction under 1.6m tall, the i3s is compact, upright, and boxy. A classically polarising design, with some crossing the street to avoid it, and others (like me) loving its unique proportions and stand-out styling.

The nose is tall, short and upright, with the distance from the base of the front windscreen to the front axle (car designers call it the ‘dash-to-axle ratio’) unusually short.

That’s because the electric motor sits in the back of the car driving the rear wheels, with only a small front boot compartment required to house charging cables and other bits and pieces.

Despite the lack of anything of substance behind it, BMW’s signature ‘kidney grille’ is present and accounted for, with swoopy LED headlights (and DRLs) either side. Our test car’s ‘Fluid Black’ finish with ‘i Blue’ highlights dialed up the little car’s charismatic personality.  

One of the i3’s most impressive party tricks is its counter-opening ‘clamshell’ doors, and the engineering trickery used to create a B-pillar free side opening (including the strength of the carbon body structure) means the high window line follows a jagged path from front to back, the rearmost hatch windows shrinking the rear glass area appreciably.

The i3s’s standard 20-inch (dual) five-spoke alloy rims, although slightly wider in this performance model, are alarmingly skinny. But taking the car’s relatively light weight (1245kg) and urban-centric purpose into consideration, the narrow, low-rolling resistance rubber makes sense.

With the roofline and sides of the car tapering distinctly towards the back, the rear view is suitably idiosyncratic, highlighted by flush-fit, vaguely U-shaped LED tail-lights. 

The hatch window is small, and the bumper sits high to marry with the load space floor sitting on top of the motor and transmission.

And when it comes to moving inside, BMW offers a choice of three ‘interior worlds - ‘Loft’, ‘Lodge’, and ‘Suite’ - featuring renewable natural fibres, recycled plastics, naturally tanned leather, and open-pore wood (sourced from 100 per cent Forest Stewardship Council-certified forestry).

But irrespective of where everything comes from, the end result is inviting, comfortable and sub-zero cool. Our car’s ‘Suite’ interior was combined with ‘Oak dark matt’ wood, and ‘Vernasca’ brown leather to stunning effect.

A tunnel-free floor, gently curved dash and digital screens for instruments and media let you know you’re in something different and special. It might be six years old, but the i3 still feels contemporary and distinctive. 

Alpina has always had a particular aesthetic that could uncharitably be termed as mid-'80s West German - all set square angles and body graphics. Think David Hasselhoff's Berlin Wall look. The company has never really deviated from adding squared-off body bits to the various BMWs it has rebadged under its long-running agreement.

For the B4S, Alpina adds the signature billion-spoke alloy wheels (only a slight exaggeration), a new front splitter complete with Alpina lettering, a weirdly proportioned boot lid lip spoiler and - not even joking - pinstripes. Like I said, mid-'80s West German. You can still recognise the sleek 4 Series Coupe but perhaps the worst of it is the super-sized, wonky-looking ALPINA B4S on the boot.

Inside is rather more restrained apart from the ill-fitting Alpina plaque under the climate control. Again, it's all 4 Series in here, with the lovely Merino leather liberally applied across the cabin. Less lovely is the wood on the door pulls and console but the door cards have an oddly appealing woven leather which looks and feels good.

Sadly the standard 4 Series steering wheel is along for the ride. There's nothing wrong with it - although the Alpina logo does look out of place - but if I were a product planner, I'd beg for the lovelier M wheel.

Wide-opening clamshell doors make getting in and out of the i3s a breeze. But bear in mind you have to open the front door to get to the latch for the back one, which can be a pain.

The driver and front passenger enjoy heaps of room, in an open environment, but there’s only a single cupholder in the centre console, so let the coffee cup wars begin.

Aside from that there are seriously big bins in the front doors, a modest glove box, and a handy elasticised pocket near the floor at the base of the bulkhead.  

Outlets for 12-volt and USB are provided, and there’s a small oddments tray at the rear of the centre console.

Slip around to the rear and you’re in anything but limousine territory. Sitting behind the driver’s seat set for my 183cm height, head and legroom are modest but do-able. And remember it’s two seats only back there.

In terms of storage, there are two cupholders between the seats but no storage pockets or bottle holders in the doors. You won’t find adjustable ventilation outlets either, but that’s not a huge factor in car of this stature.

The boot’s volume is quoted at 260 litres with the 50/50 split-fold rear seatback upright, which is enough to easily swallow the largest 124-litre suitcase in the CarsGuide three-piece set. The smaller 95- and 36-litre cases will sit side-by-side without a problem.

Fold the rear seat down and you have 1100 litres of space at your disposal, with tie-down anchors, an elasticised pocket and 12-volt power provided.

Don’t bother looking for a spare of any description, a repair/inflator kit is your only option. And not surprisingly, the i3 is a no-tow zone. 

If you're in the front, you're in luck - it's a comfortable place to be, with plenty of leg and headroom. Down back isn't terrible despite the coupe roofline. The two seats are nicely shaped for maximum comfort and separated by an odd plastic tray. The fold-down armrest has two cupholders.

Front seat passengers score a pair of cupholders (bring the total to four for the car) and the long doors will hold a bottle each.

The boot swallows a reasonable 445 litres, which isn't at all bad.

If you thought BMW don't mess about when pricing up its cars, you best strap yourself in. The 440i-based B4S starts at a solid $149,900. That's $48,000 more than the 440i and significantly more than an M4 Pure. But there's plenty of gear on offer and some genuine, bespoke Alpina additions.

Standard are 20-inch signature Alpina alloys, 16-speaker harmon kardon-branded stereo with DAB, super-soft Merino leather everywhere, dual-zone climate control, around-view cameras, reversing camera, sat nav, keyless entry and start, front and rear parking sensors, active cruise control, heated and electric front seats, head-up display, auto headlights and active LED headlights, LED taillights and electric sunroof.

The stereo and sat nav are run by BMW's iDrive. It's a cracker of a system and almost gets away without Apple CarPlay and Android Auto. The absence of such simple pleasures at this price point is a bit lame, but here we are.

The i3s is powered by BMW’s ‘eDrive’ hybrid synchronous electric motor, producing 135kW at 7000rpm, and 270Nm from 0-4500rpm. Yep, that’s right, maximum torque is delivered the instant you depress the right-hand pedal, and we’ll get to what that brings to the driving experience a little later.

The unit incorporates a charging and generator function for braking energy recuperation, the latter delivering up to 50kW.

Drive goes to the rear wheels via a single-speed (fixed-ratio) automatic transmission.

The battery powering the whole show is a 352-volt/120 amp-hour (Ah) Lithium-ion unit with a (gross) energy rating of 42.2kWh.

A lot of your extra money turns up under the bonnet. These days the 440i packs BMW's slick B58 turbo straight six and the B4S does likewise. The boys from Buchloe in Bavaria (there are certain to be women there, too, I just liked the alliteration) added a pair of Alpina-spec turbos to generate a whopping 324kW and, more importantly, 660Nm. Alpina says 600Nm (the max torque figure of the brilliant M4 CS) is available from 2000-5000rpm, while the full 660Nm is available from 3000 to 4500rpm.

The M4 Pure has 317kW and 550Nm from the S55 straight-six. Just so you know.

Like the 440i but unlike the M4, the B4S employs the dependably brilliant eight-speed ZF automatic found throughout the BMW range.

When it comes to an electric car’s energy use and projected range, there are two main things to consider - the motor’s power consumption and the battery’s capacity.

And according to BMW, the i3s’s power consumption for the combined (urban/extra-urban) cycle is 14.6–14.0kWh/100km.

Over a week, and roughly 250km of urban driving (with some brief freeway runs thrown in) we saw 19.3kWh/100km staring back at us from the on-board computer.

When BMW launched the i3 in Australia in 2014, the pure EV version came with a 60Ah battery pack delivering a claimed 130 kilometre range (a range extender model featuring the addition of a two-cylinder petrol motorcycle engine was also offered). 

In 2016 a 94Ah version arrived to boost range up to 183km, and the i3s launched in 2018, with its 120Ah battery pushing range out to BMW’s current, real-world estimate of 260km.

Then, there’s charging time, which is like asking how long is an electric piece of string.

According to BMW, for a 0–80 per cent charge from a (50 kW DC) fast-charging station, you’re looking at 45min.

From a (11kW/16A/380V) high-output home/office wall unit, that pushes out to 3.10h, and using a (3.7kW/16A/240V) low-output home/office unit stretches the wait time to 9.40h.

BMW offers the ‘WallBox plus’ charging suite as a dealer accessory priced from $1990 (not including GST or install costs).

Plug into a domestic (2.4kW/10A/240V) socket, and you’re staring down the barrel of 15.00h. But at least you can use low-cost, off-peak energy overnight, right? Nah, I don’t buy that line either.

Alpina quotes 7.9L/100km on the combined cycle and we went through the premium unleaded at the rate of 11.7L/100km. I enjoyed myself, so that's not a terrible result.

It might not look like a conventional sports car, but the BMW i3s certainly accelerates like one, with a claimed 0-100km/h time of 6.9sec. The i3s is a smile-inducing hoot to drive.

Every one of this little hatch’s 270 newton metres of torque is available from the minute you hit the accelerator pedal, and remain in service until 4500rpm, at which point torque delivery drops off a cliff.

But peak power steps in at exactly 7000rpm, so if you’re determined to make that overtaking move you won’t be left in the lurch. In fact, BMW says it only takes the i3s 4.3 seconds to surge from 80km/h to 120km/h.

However, the i3’s forte is 100 per cent the city, rather than the open road. Its ‘point and squirt’ ability making it the perfect partner for the cut and thrust of the urban jungle.

The i3s features an upgraded ‘Sports Suspension’ incorporating firmer dampers, re-tuned springs and revised anti-roll bars. It’s also lowered 10mm, the track is widened (+21mm front / +2.0mm rear) and the wheels go plus one inch to 20-inch alloys.

The standard i3 (no longer offered in Australia) rolls on 19-inch rims shod with 155/70 rubber all around. And while the i3s’s 175/55 front and 190/50 rear tyres are still exceptionally narrow, from the side the low-profile Bridgestone Ecopias look like fan belts wrapped around pulleys rather than tyres around wheels..

No surprise then that ride comfort isn’t exactly cushy, and in signing on for the i3s experience you’ll need to be ready for more than occasional bumps and thumps.

But the pay-off is super-sharp dynamics, Suspension is by alloy struts at the front, and a five-link alloy set-up at the rear..The steering responds to inputs quickly yet smoothly, and with 48/52 front to rear weight distribution, the car always feels balanced, eager, and taut.

And if you really want to dial things up the ‘driving experience control’ allows a switch to Sport mode for a further tweak of the suspension, steering, and traction control set-ups.

A tight 10.3m turning circle makes for easy parking and stress-free U-turns. But if things get too tight, rapid three-point turns are assisted by the gear shift controller bring mounted on a chunky stalk on the right-hand side of the steering column. Too easy.   

Braking is by vented discs front and rear, but they’re tiny. That’s because the ‘Brake Energy Regeneration’ system does most of the work. 

Effectively turning the motor into a generator, the system not only slows the car dramatically but feeds energy to the battery in the process. It takes a while to get used to the sensation, but soon becomes a fun, and surprisingly easy game to use the brake pedal as little as possible… often not at all, for long periods.

One of the key differences between the B4 and M4 is the ride. While the M4 can crash over bumps and generally be a little hard to live with, the crew in Buchloe have gone after a much more plush ride. And in that they have succeeded because the B4 S is a mighty fine cruiser. Bumps are dismissed with a haughty disdain, even Sport + silliness doesn't completely write-off ride quality.

Very impressive too, is the steering. While still not at Lotus Elise levels of feel (few cars are), the Alpina tweaks connect the your palms to the road with more clarity than what you'll find in the 440i or M4. Where the M4 particularly adds too much weight, the 440i is a bit more circumspect in that regard.

And then we come to the engine. The B58 six is a belter, better even than the N55 that preceded it. It's still a 3.0-litre straight six but is part of BMW's modular engine family that starts with a 1.5-litre triple in the Mini and 1 Series. The Alpina-spec turbos are noisier, the Akrapovic exhaust lighter and also noisier. It doesn't have the all-out crackle and pop of an Audi or Merc (perish the thought), but when you're on it, the B4 means business. The 660Nm of torque, available over a wide rev range, delivers a steel fist wrapped in a velvet glove and bubble wrap - the speed builds rapidly but smoothly. 

The approach to the chassis tune seems to be based on the driving talents of mere mortals on normal roads, which is kind of like the 440i. It's terrific fun to drive hard but it's very forgiving and patient. The great thing about it is that you wouldn't think twice about jumping in it for the long haul, so comfortable and quiet is the cabin. The M4 will leave it for dead on a winding road, but that's perfectly fine.

One irritant is the replacement of the admittedly cheap BMW gearshift paddles with weirdly non-tactile buttons. They're not particularly easy to use and, probably worse for a sporty car, unsatisfying. It's an odd detail with which to go off the reservation. Cheeringly, the eight-speed ZF is its usual perfect self, so you don't have to worry too much about manual mode or go old school and use the shifter.

The Alpina ships with six airbags, ABS, stability and traction controls, ABS, stability and traction controls, forward collision warning, forward AEB, road sign recognition and active cruise control.

There are also two ISOFIX points in the rear. Neither the Alpina nor the 4 Series has an ANCAP safety rating.

BMW offers a three year/unlimited km warranty, which is off the pace given the majority of mainstream brands have stepped up to five-year cover, with some at seven. And the pressure is on with Mercedes-Benz recently announcing its shift to five years/unlimited km.

That said, the BMW's body is warranted against rust (perforation) for 12 years/unlimited km, and roadside assistance is provided free-of-charge for three years/unlimited km.

Maintenance is 'condition based' with sensors and on-board algorithms (mileage, time since last service, driving style) determining whether an annual vehicle inspection is required.

The 'BMW Service Inclusive' package, offering a single, one-off advance payment to cover selected service and maintenance costs, is available in two levels - 'Basic' ($850) or 'Plus' (dealer quote)

Alpina offers a two-year/unlimited-kilometre warranty which is a bit behind the times and not in keeping with the price point. Servicing is another matter altogether and you're subject to your dealer's standard charges for servicing.