First drive: BMW i4 M50 xDrive prototype review

It gets a long bonnet, a heavily raked windscreen, frameless doors, flush external door handles and a high-set, notchback-style rear end. This hosts a small lip spoiler that's part of quite an extensive range of M styling touches on the M50.

The traditional proportions may appeal to existing BMW customers, but to these eyes, it lacks the modernity that's evident in the design of many recent dedicated EVs, including BMW’s own iX.

Dimensionally, it’s not too far removed from the latest 3 Series, with a length of 4785mm, a width of 1852mm and a height of 1448mm. It also rides on a wheelbase that's just 4mm longer than BMW’s ICE-powered junior saloon, at 2856mm.

Inside, the i4 adopts a combination of new and existing design elements. There’s a new curved digital panel housing the instruments and infotainment functions atop the same lower dashboard as that used by various other BMW models, including the latest 3 Series and 4 Series.

A lot of this was covered in our prototype, but the driving position and overall ergonomics felt welcomingly familiar and spot-on for a car that aims to combine genuine everyday liveability with a good dose of sporting flair.

Don’t expect 3 Series levels of accommodation and load-carrying ability, though. It’s fine up front, but the curved roof restricts head room in the rear and the 420-litre boot is 60 litres smaller than that of the 3 Series.     

The M50's fifth-generation EV powertrain is largely shared with the iX. It consists of two electric motors: one on the front axle with 255bhp and another at the rear with 308bhp. Together, they develop a combined system output of 536bhp, or 33bhp more than the twin-turbocharged 3.0-litre straight six in the M3 Competition. No less significant is the torque: with a combined 586lb ft, it offers 107lb ft more.

For perspective, the Porsche Taycan 4S’s dual-motor drivetrain can boast maximum outputs of 483bhp and 479lb ft.

The M50's headlining reserves are, however, only unleashed in full brief periods in Sport Boost mode. In other driving modes, its BMW-developed and -produced motors deliver a nominal 469bhp and 538lb ft (which is some 100bhp and 169lb ft less than that set to be offered by the upcoming petrol M440i Gran Coupé).

An 80.7kWh (net) lithium ion battery sits underneath within the wheelbase. It comprises four modules, each containing 72 cells, and is bolted to the floorpan in a process that's claimed to add rigidity to the overall structure.

Making use of all possible space, there’s also an additional section of the battery housed within the centre tunnel in the place usually taken up by the driveshaft on ICE 4 Series models. It's made up of three modules, each with 12 cells.

The new-generation battery uses NMC811 prismatic cells, enabling BMW to claim a 40% improvement in energy density over the seven-year-old i3. It gives the M50 a range of 317 miles on the WLTP cycle – 53 miles short of its rear-driven eDrive40. It operates at 400V and can be charged at rates of up to 210kW by a DC unit.

You start the M50 like any other modern BMW, with a press of a button on the centre console. There’s no electrical whirring, just silence.

It moves away in a wonderfully smooth manner. The two motors are super responsive. The throttle is also superbly calibrated, allowing you to meter out the power well. This all makes for tremendous ease of driving in everyday situations, where the M50 is both tremendously well refined and sufficiently powerful to give it very brisk qualities.

Find an open road and you’re able to confidently exploit the full reserves of the latest M Performance car to stunning effect. Dialling up Sport Boost mode heightens the performance further, bringing an added 67bhp and 48lb ft. There are also sharper qualities to the throttle and with it even greater response from the drivetrain.

So configured, the M50 surges off the line. It builds momentum with extremely linear properties, propelling you forward with considerable force in the process. The generous torque fully compensates for the car's considerable weight, making for hugely responsive tip-in and rather intense roll-on acceleration. The urgent feel doesn’t begin to trail off until you’re well on your way to three figures and beyond.

The M50 is a very fast car when you want it to be – perhaps not quite in the same league as the Taycan Turbo but every bit as strong as the Taycan 4S. The initial thrust on a loaded throttle is intense. From then on, it accelerates in a truly effortless manner.

The performance is deceptive. Apart from a whoosh as air across the windscreen and some well-suppressed tyre roar, there’s little noise to signal your speed. BMW does offer the option of a sound generator, but this didn't feature on the prototype we drove.

So how fast is it, exactly? BMW claims 0-62mph in 3.9sec in combination with a launch control function, which is 0.1sec quicker than Porsche quotes for the Taycan 4S. Top speed is limited to 140mph, restricted by BMW’s decision to stick with a single-speed gearbox rather than adopting a twin-speed unit like the Porsche, which can hit 155mph.

The quick-acting four-wheel drive system plays a crucial role in the performance potential of the M50. It's integrated with the chassis control system, providing a fully variable apportioning of drive between the front and rear axles, going from pure rear-wheel-drive to four-wheel-drive depending on the driving conditions.

Traction was quite striking in combination with 245/40 R19 (front) and 255/40 R19 (rear) tyres fitted to the prototype we drove. Whether fired off the line or called upon when loaded up with lateral forces at the exit of corner, the car always found plenty of purchase.   

Satisfaction in driving the M50 doesn’t come only from exploiting its substantial reserves, though. An advanced energy-recuperation system also urges you to harvest as much kinetic electricity as possible when the conditions allow. There are two modes: D selects an adaptive recuperation mode which favours off-throttle coasting and takes into consideration topographic information from the navigation system, while B triggers a more brake orientated recuperation mode capable of generating up to 261bhp – all of which flows back into the battery for use later.  You can alter the amount of regeneration between low, medium and high via the iDrive menu, with high providing quite strong braking force and one pedal-driving at lower speeds around town.

While the M50 lacks the overall on-road intimacy of an M3, its dynamic properties are very accomplished. To accommodate its electric driveline, it gets 26mm-wider front and 12mm-wider rear tracks than other 4 Series models.

It retains MacPherson strut (front) and multi-link (rear) suspension set-ups, but the latter adopts air springs as standard. Additionally, there are extra bracing elements within the engine bay and at the rear to stiffen up the overall structure.

To counteract the weight brought on by its vast battery, the ride height is increased by 20mm. However, BMW's effort in packaging the driveline within the floorpan is claimed to provide the i4 with a centre of gravity up to 37mm lower than that of its ICE siblings. That might not sound like much, granted, but the handling – most notably the way it controls its mass – is outstanding when you choose one of the sportier driving modes.

You’re always aware of the car's weight, but with a 48:52 front-to-rear weight distribution, the M50 feels wonderfully balanced. And while its electromechanical steering isn't exactly overflowing with feedback, it makes the M50 change direction smartly, with the sort of eagerness that you expect of a car wearing the revered M badge.

It also generates impressive grip. The xDrive system is programmed to deliver predominantly rear-wheel-drive qualities, and you can feel the torque-vectoring effect of the electronic rear differential in all-out cornering. However, it's quick to shift drive to the front wheels to keep things on a neutral footing. There’s an assured level of mid-corner purchase and, with all that torque, exceptionally strong drive at the exit. Push hard and you will experience some understeer on turn-in, although the smoothness of the throttle allows it to easily adjusted.

There’s an inherent firmness to the underpinnings in keeping with the M50's sporting brief, and the added ride height attributes to some fleeting floatiness over undulating roads, but the control of body movements in general is very good, giving the car an engagingly flowing gait.

The ride, meanwhile, is nicely composed, thanks to the ability of the air springs to adjust ride height. It's occasionally upset by high-frequency bumps and more demanding transverse ridges. However, the adaptive dampers are quick to react, leading to fitting levels of comfort together with exceptional refinement.