BMW M4 Competition Convertible

The new generation of BMW M3 and M4 represents a radical departure from their long line of esteemed predecessors. M Division’s latest spearhead, the G80-series, is all-new, based upon BMW’s versatile CLAR modular platform.

Topping the M3/M4 range with a base price of $176,900 ($11k over an M4 xDrive coupe), this M4 Competition Convertible isn’t what you’d call cheap. Those are stout figures, however, when you consider that a Porsche 911 Cabriolet yields a 92kW/100Nm disadvantage while wielding an $86,000 premium.

It should outrun the Porsche from the traffic lights, too, as the adoption of all-wheel drive drops the M3/M4’s 0-100km/h time from 3.9-seconds to 3.7-seconds, compared to the 911 Cab’s blousy 4.4-second claim.

As expected, it’s grown in size, measuring 123mm longer and 26mm wider than the superseded F8x generation. A 45mm increase in the wheelbase also delivers improved rear legroom and aids stability at speed.

Unlike the previous F83 M4 convertible, the new G83 trades the old folding metal roof for a more conventional fabric softop, delivering a 40 per cent weight saving and freeing up an additional 80 litres of stowage space in the boot.

Naturally, however, lopping metal off the top invariably means adding more metal down there. BMW has gone to great lengths to minimise the loss of body rigidity in the open-top M4. A unique aluminium shear panel has been affixed to the xDrive-specific double-joint spring strut front axle subframe, with its five-link rear axle rigidly-mounted to the body along with unique torsion struts and specially tuned elastokinematics and kinematics. The M4 convertible has also benefited from a bespoke steering ratio and geometry.

Factor in the added componentry of the xDrive system, and the G83 M4 convertible tips the scales at a portly 1995kg. That’s 205kg more than the preceding M4 convertible, 265kg more than the current rear-drive M3 Competition and, astoundingly, 25kg more than the outgoing X3 M Competition SUV.

Despite weighing nigh on two tonnes, the M4 Competition convertible disguises its added mass well thanks to the deep well of power and torque produced by the S58 inline-six.

Superficially, the basics appear similar to the old S55, sharing its twin-turbo inline configuration and 3.0-litres of swept capacity. In truth, however, the new S58 differs in the details by way of its stronger closed-deck construction (a boon for power tuners), forged crankshaft, longer stroke (increased to 90mm), lower compression (9.3:1 v 10.2:1) and breathes in more boost through two mono-scroll turbines (maxing out in Competition trim at 18.9 psi).

Developments under the bonnet improve efficiency and emissions as well as performance. A peak of 375kW is delivered at 6250rpm, with a maximum of 650Nm on tap between 2750 and 5500rpm – 1400rpm lower than the old S55.
We’ll get to the fast stuff in a minute, however.

Hit the centre console-mounted starter button and set off down the road and, instantly, you can tell that the new series of M3 and M4 are vastly different to their predecessors. It feels dense, and surefooted, with markedly improved low-speed comfort and damping.

There’s still an underlying firmness, but it no longer crashes and jolts over bumps and small potholes like the previous generation did. Reaching for Sport, and even Sport Plus, suspension modes on anything other than manicured tarmac is no longer an exercise in masochism. Impressive, considering the car rolls on staggered 19/20-inch alloy wheels shod in low-profile 275/285 tyres.

The ZF eight-speed torque-converter auto quells much of the old dual-clutch’s urban idiosyncrasies. Shifts are solid, but it’s a much smoother unit in traffic and urban settings. I did find that Auto Hold function caused a moment of hesitation followed a by slight shunt upon take off. Disabling Auto Hold and contending with the minor drivetrain creep resulted in far smoother progress.

It can feel slightly hesitant to respond from idle due to a lazy throttle calibration in comfort mode, and a lower compression motor working through some slight turbo lag. Once it gets going, which doesn’t take long, the M4 is a seriously quick machine.

Even more impressive, however, is the effortless mid-range response. For the quickest and most discreet point-to-point transport, you’ll be leaning on the S58’s prodigious torque loads more than top-end power, short-shifting and keeping the digital tachometer needle plugged into the meaty mid-range.

Despite a 7200 rpm redline, you essentially never need to exceed 6000rpm as there’s little payoff to be found up there. Certainly not the aural kind either.

Fitted with two petrol particulate filters, the latest M4 doesn’t boast the histrionic bark of certain other rivals, but it still sounds purposeful and tough from the inside. BMW’s Active Sound Design feels more organic and authentic, but you get the feeling that the car is never as loud from the outside as it is from inside the cabin. The active exhaust button on the centre console doesn’t add much volume, instead dropping the note a semitone or so with more rumble on idle.

With the roof up, cabin noise is well-contained, dominated by a slight wind rustle – though that’s to be expected of any soft-top convertible. When the surface changes to coarser tarmac, the dominant sound switches from wind noise to a dull tyre roar – this car coming fitted with a bespoke BMW blend of Pirelli P Zero.

It was a near-30 degree day up on Victoria’s Lake Mountain, and by the day’s end the the rubber was audibly signalling its displeasure on the cruise back down to Marysville. The front end remains composed, however, progressively easing into understeer which is easily remedied with a nudge of throttle.

Any concerns that the adoption of xDrive has sanitised M Division’s MVP can be laid to rest. It’s a sophisticated system that feels seamless, primarily feeding power to the rear wheels and only to the fronts when the vehicle senses extra traction is needed. About the biggest compliment you can give it is that if you weren’t told, you’d be hard pressed to guess it had a pair of front driveshafts. Any notion of torque steer is completely absent.

Driving the M4 convertible quick is still an involving experience, even with everything in its most relaxed settings, the M4 will give frequent hints of neutrality if you begin playing with lateral inertia, and will wiggle its hips just so on corner exit under throttle.

It might lack the white-knuckled thrill of the rear-drive car, but for some that’s like saying you miss the thrill of skydiving or snake charming. In a pure performance sense, the xDrive simply feels better equipped to deploy this impressive level of power, adding a light touch of composure to the effortless consumption of kilometres.

There are even more layers to discover once you delve into the various configurable settings within the drive modes menu, easily engaged by the button near the shifter. Settings for engine mapping, transmission speed, adaptive dampers, steering, brake-by-wire response and ESC all offer varying levels of ferocity.

M Dynamic Mode (MDM), a loosened ESC setting, barely distinguishes itself from a fully engaged system, and certainly doesn’t yield the sublime generosity found in the rear-drive manual non-Comp M3 we drove recently. Turn ESC off and lock the car into its permanent 2WD mode, and there are ten settings of traction control to experiment with. This also unlocks BMW’s gamified M Drift Analyser that will score your yaw readings out of five stars.

Wick everything up and the steering becomes quicker and weightier, providing more immediacy on corner entry and more feedback from the front end.
With brakes in Sport, pedal travel to the bite point is reduced and more sensitive, although on the road this can narrow the window of modulation.

There’s little detectable difference between the three transmission speeds and, even at its fastest, still feels more cogent and cohesive than the old twin-clutch.

While the xDrive M4 Convertible disguises its kerb weight through the sheer ease in which it piles on pace, combined with its high-levels of grip, there is increased body roll to contend with, and you’ll feel its heft under rapid direction changes and moments of hard braking; forcing a pause as you wait for the car to settle on its springs.

Scuttle shake was minimal, appearing only a few times and is primarily felt through the steering column. There were only a couple of instances of momentary body shudder over heavily corrugated tarmac when really pushing.

But few M4 Convertible owners will likely be seeking ten-tenths of limit performance. So while the open-top M4 may concede minor dynamic ground to its fixed-head siblings, and their manual rear-drive availability promises the ultimate enthusiast experience, the xDrive M4 convertible arguably delivers the most versatility and widest bandwidth in the everyday experience with the added lifestyle perks of open-air motoring.

In many ways, it almost feels like you’re getting two, maybe even three, cars for the price of one.

In that respect, as an ownership proposition, you might find that the most expensive M4 in the range also has the most to give.

2022 BMW M4 Competition xDrive Convertible technical specs