The all-new BMW M4 Convertible arrives in US showrooms late this summer to join the M4 Coupe and M3 Sedan. The 2015 BMW M4 Convertible is powered by the same BMW M TwinPower Turbo 3.0-liter inline-six as its siblings. That engine produces 425 horsepower and 406 lb-ft of torque and can be mated to either a 6-speed manual or 7-speed M-DCT transmission. The new BMW M4 Convertible makes its world debut at the 2014 New York International Auto Show.
Like the new BMW M3 Sedan and new BMW M4 Coupe, the new M4 Convertible sees a return to an inline-six engine, as used on the second and third generations of this iconic open sports car. The new turbocharged engine combines the best of both worlds – reaching a maximum 7,600 rpm, it is unusually high-revving for a turbocharged engine, resulting in linear power delivery over a wide engine speed range and a soulful engine note, while M TwinPower Turbo technology ensures that peak torque is on tap over a broad rpm range. A further hallmark of this engine is its outstanding efficiency.
The new engine sees a power upgrade over the previous V-8 to 425 hp, which is delivered between 5,500 and 7,300 rpm. Peak torque has been increased by roughly 40 percent to 406 lb-ft, and is maintained over a very wide rev band (1,850–5,500 rpm). The sprint from zero to 60 mph takes the new BMW M4 Convertible just 4.4 seconds with the 6-speed manual. Equipped with the 7-speed M Double Clutch Transmission, this number falls to 4.2 seconds. Top speed is 155 mph (electronically limited). The BMW M TwinPower Turbo engine hits maximum revs of 7,600 rpm, in keeping with the typically high-revving character of M engines.
Power transfer in the BMW M4 Convertible is via a standard six-speed manual gearbox. Available as an option is the seven-speed Double Clutch Transmission M-DCT, which allows the driver to change gears not only using the selector lever in the center console but also via the shift paddles on the steering wheel. This transmission effectively combines two gearboxes, each with its own clutch. This means gear changes are executed with no interruption in the flow of power – and the shift processes are therefore shorter. Drivelogic allows the driver to select from different shift modes, which see the M4 Convertible adopting a particularly comfort-oriented, economy-focused or ultra-sporty approach to gear changes when in automatic mode. The Launch Control function also integrated into M-DCT enables optimum acceleration off the line.
The standard Active M Differential optimizes traction at the rear axle. The electromechanical steering system, meanwhile, represents a new development from BMW M GmbH and is the critical component in the link between driver and car. It offers the gifts of direct steering feel and precise feedback. The integrated Servotronic function electronically adjusts the level of steering assistance according to the car’s speed, providing optimum steering characteristics at all speeds. Three steering settings (COMFORT, SPORT and SPORT+) can be selected at the touch of a button to adjust the level of steering assistance to the situation at hand and to the driver’s personal tastes.
The optional Adaptive M suspension likewise comes with COMFORT, SPORT and SPORT+ modes. The BMW M4 Convertible is equipped as standard with M compound brakes, but customers can also order their car with even lighter and more effective M carbon ceramic brakes, which boast the additional visual highlight of gold-painted calipers.
As well as outstanding dynamic qualities, intelligent lightweight design also allows the BMW M4 Convertible to claim exemplary efficiency. Its extensive weight-saving measures produce a curb weight of just 4,055 lbs – around 90 pounds less than its predecessor.
Drivers of the BMW M4 Convertible can look forward to piloting their car from behind a double-spoke M leather steering wheel. The M logo, chrome trim and color contrast stitching are central elements of the cabin’s racing ambience. The M4 Convertible comes standard with a 6-speed manual gearbox, while the 7-speed M Double Clutch Transmission is available as an option. M-DCT allows the driver to change gears using either the selector lever on the center console or the shift paddles mounted on the steering wheel.
The BMW M4 Convertible offers outstanding everyday driving qualities and a dynamic design, with the top up or down. These seemingly contradictory qualities were already combined in the BMW M3 Convertible, the predecessor that set standards for premium mid-size convertibles. The hardtop of the BMW M4 Convertible features a number of design improvements that reduce noise levels for a much quieter interior ambience. The sound-absorbing headliner also reduces wind noise by up to 2 dB in comparison to the predecessor model.
When the top is up, the luggage compartment has a volume of 13.0 cu. ft. (370 liters) – that is 0.7 cu. ft. (20 liters) more than available in the BMW M3 Convertible. All trunk volumes are based on ECE measures. Even bulky items can be transported with the BMW M4 Convertible. A flat and level storage area can be utilized when the backrest of the rear bench seat is folded down. The load-through feature, which is standard in the US, makes even more space available: Either a wide opening between the rear passenger compartment and the trunk, or a smaller opening, for skis for example, when four people are seated in the vehicle. All it takes is the push of a button to transform a dynamic coupe into an elegant, athletic convertible in a mere 20 seconds. The top can also be lowered when the vehicle is travelling at speeds of up to 18 km/h (approx. 11 mph).