The New M4 Convertible
Every M3 model produced has been offered with a convertible option and many people have been waiting patiently for the M4 to offer a similar choice. Fortunately, that wait is over.
Introducing the 2015 BMW M4 Convertible.
The high-end German automaker has been busy this year – already unveiling heavily redesigned 3/4 Series models and M3 Sedan/M4 Coupes – but it appears that they may have saved the best for last. Officially introduced at the 2014 New York Auto Show, the M4 Convertible is an impressive piece of machinery to say the least.
Overview
The new M4 shares many of the same features and styling cues as the new M3 Sedan and M4 Coupes released months ago including a powerful 3.0 Liter Twin-Turbocharged Inline Six Cylinder engine turning out 431 horsepower.
Like the 4-Series convertible, the M sports an attractive three piece retractable hardtop complete with a standard windbreaker for U.S. markets. The top is fully retractable in 20 seconds at speeds up to 11 MPH and includes improved sound absorption over previous M3 convertible models.
The addition of the retractable roof does add 525 pounds to the overall vehicle weight compared to the Coupe; tipping the scales at just over 4,000 lbs. That said, BMW went to great lengths to redesign the chassis for weight savings and improved handling by implementing Carbon Fiber Reinforced Plastic throughout the chassis and powertrain. The result is a net savings of 90 pounds over the old M3 Convertible.
The exterior looks almost identical to the coupe version previously released with the exception of the trunk area which was redesigned to accommodate the retractable roof. Despite the storage space needed for the roof, BMW was able to squeeze an additional 0.7 cubic feet of cargo room with the roof up and an impressive 7.8 cubic feet with the top down into the new design.
Powertrain
The heart of the M4 is the BMW M TwinPower Turbo 3.0L Inline Six; the same motor found in the M3 Sedan/M4 Coupe. At 5,500 RPM, this engine produces 431 horsepower and an impressive 406 lb-ft of torque. TwinPower technology translates into smooth torque delivery throughout the RPM range.
Coupled to a six-speed manual transmission, the 3.0L motor is capable of 0-60 in just 4.4 seconds. With the 7-speed M Double Clutch Automatic transmission, 0-60 time is reduced to just 4.2 seconds. Top speed is electronically governed at 155 MPH and redline is at 7,600 RPM; unusually high for a turbocharged engine.
CFRP is used to create a single piece driveshaft (with no center bearing) that reduces rotating mass by 40%. This weight savings improves overall performance by delivering power more quickly and efficiently. Other improvements include a new cooling system with an indirect intercooler to maximize charge pressure and two side-mounted water coolers designed for high and low temperature water circuits.
To top it off, the new power plant is extremely efficient – boasting 31 MPG highway due to the seamless integration of Valvetronic variable valve timing and Double VANOS continuously variable camshaft timing.
Chassis
BMW has done an excellent job of improving a vehicle already renowned for its exceptional handling this year.
The electromechanical steering system offers the driver the perfect combination of direct steering feel and precise feedback and includes integrated Servotronic functionality that adjusts steering assistance according to vehicle speed.
Push button steering settings are also available to the driver including: Comfort, Sport and Sport+ modes. These settings allow the driver to select the level of steering assistance based on driving conditions and preference. The optional Adaptive M suspension package also offers the same driver-selected modes.
CFRP is used to create a superiorly rigid engine strut brace weighing only 3.3 pounds. The improved strut design is an integral part of the vehicle’s exceptional handling and offers a substantial weight savings over conventional aluminum struts.
At the other end of the vehicle, the Active M Differential improves traction and directional stability using an electronically controlled multi-plate limited slip differential. The Active M Differential is automatically regulated by the Dynamic Stability Control system and takes into account factors such as the position of the accelerator pedal, the vehicle’s yaw rate and the rotational speed of the wheels for total control of the drive axle.
The speed at which the Active M Differential functions is also impressive. Rear axle lock can be modified between 0% and 100% in a fraction of a second as needed to provide optimum traction in any driving or road condition.
Exterior
Upon seeing the new M4 for the first time, there is little doubt of its heritage. Powerful contours and a modern variation of the twin headlight arrangement – coupled with a distinctive grille – let other drivers know that this is a performance machine that also looks the part.
Other notable exterior improvements include the signature power dome hood, twin-stalk style mirrors and flared front and rear wheel arches housing 18” (or optional 19”) custom M wheels.
Like everything with BMW, these exterior features are as much about function as style and ensure that the newest addition to the BMW family is worthy of its name.
Interior
There is no shortage of innovation inside the vehicle either. From the optional Head-Up Display unit stuffed with additional M-specific features to the perfectly balanced ergonomics and traditional “M” interior touches, there is little left to the imagination when sitting in the driver’s seat.
Other interior features may already be familiar from the M3 Sedan and M4 Coupe such as BMW ConnectedDrive features which include an improved Navigation System, Active Driving Assistant and Intelligent High Beam Assistant.
The New BMW M4 Convertible is scheduled to arrive in showrooms this summer…just in time to put the top down and enjoy the experience for yourself.