New York show: BMW adds M to 4 Series convertible

BMW has unveiled an M-badged version of the 4 Series convertible, that can make the sprint to 100km/h in just 4.4 seconds, ahead of a world public debut inNew York this month.

Featuring the same twin-turbocharged 3.0-litre inline six-cylinder engine as the two-door M4 Coupe, the M4 cabriolet’s powerplant is good for 317kW of power and 550Nm of torque – up over the free-breathing 309kW/400Nm V8 it replaces in the old M3 convertible.

Peak power arrives at 5500-7300rpm, while the maximum torque arrives across a much wider rev range than the V8 it displaces, from 1850-5500rpm.

The newest 4 Series model to wear the M badge will make its global debut alongside the X4 SUV at this month’s New York motor show.

The extra power and a slight drop in weight – the 1750kg drop-top M4 sheds about 60kg compared with the model it replaces despite a hefty increase in the amount of under-body strengthening – cuts 0.7secs off the 0-100km/h sprint.

It is, however, still three-tenths slower than the lighter M4 coupe revealed in January and due here in July.

This time refers to cars fitted with the optional M-spec dual-clutch automatic transmission with a launch control function. With the six-speed manual it is 4.6s. Top speed is an electronically-limited 250km/h.

Cornering prowess is helped by a clever “Active M” rear differential that can push drive to the outside wheel while powering out of a corner, helping to twist the M4 convertible around a curve.

However, despite all the hype about its performance, the new M4 convertible will officially use a combined 9.1L/100km on the European cycle.

Similar to the 4 Series convertible range launched in Australia earlier this month, the M4 convertible will allow the driver to drop the three-part roof in 20 seconds, and at speeds of up to 18km/h.

It carries over the same long bonnet, although with a significant power hump denoting the potency under the bonnet, and short front and rear overhangs as the rest of the 4 Series convertible range. The hard roof, meanwhile, provides the same graceful pillar-less coupe design as the previous generation of the M-badged car.

The bonnet, front guards and many of the chassis and suspension components are made from aluminium, while lightweight carbon fibre-reinforced plastics are used for the prop shaft and rigidity-enhancing engine bay strut.

Up front, the unique M-tuned suspension carries heavy duty double-joint springs, while down the rear the five-link suspension is mainly made from aluminium.

The M4 convertible carries the same longer wheelbase and wider track as the rest of the 4 Series range when compared to the 3 Series it replaces, promising much sharper dynamics than its predecessor.

The steering features a variable electric-assist rack-and-pinion set-up.

As with the more pedestrian versions of the convertible, boot space is a handy 370 litres with the roof in place, falling to 220L when it is stowed.

At 4670mm in length, 1870mm in width and 1386mm in height, the new car is 56mm longer, 65mm wider and 4mm lower than its predecessor The drop-top M4’s fit-out closely follows that of the range-topping 435i, with features such as seatbelts integrated into the front seats, and an in-seat “Air Collar” neck warmer.

One feature that will stand alone on the hi-po convertible is an illuminated “M” logo built into the front seats.

While the new drop-top is expected to go on sale in Europe later this year, Australian buyers could face a long wait to get behind the wheel, with the M4 convertible’s arrival likely to be pushed back to next summer at the earliest.

BMW Australia is already expecting a busy year of new-model roll-outs in the year ahead, including the closely related M3 sedan and M4 coupe, the high-riding X4 coupe, front-wheel-drive 2 Series Active Tourer and the battery- or hybrid-powered i3 hatchback and i8 all due to land here before the sun-loving M4 does.