As sure as night follows day it was only a matter of time before the M version of the new BMW 4 Series Convertible arrived to join the M4 Coupé and M3 Saloon, and here it is. For those still at a loss to explain where the 4 Series sits in the manufacturer's line-up, it is the 'sportier' side of the junior BMW family, offered in Coupé, Gran Coupé and Convertible guises. All of which means the M4 Convertible you see before you is the successor to the M3 Convertible. Confused? Don't be, as all you need to know is that this drop-top packs a twin-turbocharged punch that is sure to get the wind in your hair.
Exterior
Aggressive yet stylish would probably be the best way to describe the M4 Convertible, sort of like taking an MMA fighter and fitting them out with a perfectly tailored suit straight from Saville Row. Signature M identifiers like the power dome on the bonnet and flared arches front and rear are the muscles to the exquisitely cut roof-folding mechanism, which, thanks to the loss of the B-pillar, leaves an uncluttered profile when driving al-fresco.
Forged alloy wheels serve as the rolling stock with 18-inch units as standard and 19s available from the options list. Like its Saloon and Coupé siblings the M4 Convertible sports some trick aerodynamics such as the lift reducing front apron and smooth underbody. The 'Air Curtains' in the front bumper also work to cool the brakes before exiting through the M gills behind the front wheels, ensuring air turbulence is kept to a minimum.
This MMA fighter has also gone on a diet, dropping 60kg compared to its predecessor despite being a larger car overall. Chief amongst the weight saving measures is the extensive use of aluminium for not only the chassis but also the bonnet and front wings. Carbon-Fibre Reinforced Plastic (CFRP) has also been used for parts like the drive shaft and front suspension strut brace.
Interior
Seating in the M4 Convertible is purely for four with front occupants getting electrically adjustable leather sports seats. Those in the rear also enjoy individual thrones. Bespoke 'M' trim covers the interior from the three-spoke steering wheel to the unique, white backed instruments and from the gear lever to the driver's footrest.
Mechanicals
The engine in the M4 Convertible is a veritable Smorgasbord of BMW's best work: 3.0-litre straight-six engine? Check. TwinPower turbo technology in the guise of two turbochargers? Check. Valvetronic and Double Vanos? Check and check. The result is an engine that is said to crave the redline in the way the naturally aspirated V8 that came before it did while offering up peak power of 431hp (produced between 5,500- and 7,300rpm) and 550Nm of torque (on tap from 1,850- to 5,500rpm). With the standard six-speed manual transmission this means a 0-100km/h time of 4.6 seconds and the optional seven-speed M Double Clutch Transmission (M DCT) shaves 0.2 seconds off that.
Whatever the gearbox, top speed is limited to 250km/h and the new car delivers fuel consumption of 9.1 litres/100km (8.7 litres/100km for the auto) with emissions of 213g/km (203g/km for auto). Though we doubt anyone in the market for a car such as this will be too concerned with these figures. Of more import is the fact that the fancy CFRP drive shaft leads to an updated version of the Active M differential, which can shuffle power along the rear axle in a fraction of a second, and that the exhaust system features electronically controlled flaps that "help create an unmistakable BMW M sound."
Anything else?
Naturally, being an open car, getting the roof off the M4 Convertible is of paramount importance. Thankfully, at speeds of up to 18km/h this action is completed in 20 seconds with the simple flick of a button, and the tri-fold roof stows away into the boot. Roof open the luggage capacity is 220 litres or 370 litres with it closed. Protected from the elements the M4 Convertible is said to be 2dB quieter than its M3 Convertible predecessor thanks to the 'noise absorbing' headliner.
No word in the press release on whether or not the drop top features the same 'Smokey Burnout' function as the saloon and coupé, which "allows the driver to indulge in a degree of rear wheel spin while the car is moving at low speeds." We have to assume it does, but if not, it does mean the Convertible is off our shopping list...
Update: BMW Ireland announced this morning (April 4) that the new M4 Convertible will be launched here on September 6th this year, starting at €108,300 on-the-road.