The hardtop brings the Z4 in line with the competition, opening and closing in 20 seconds. The weight penalty is offset by greater security, better visibility and greater comfort. The side windows are 40% larger than the outgoing soft-top model, and the rear window is fully 52% larger. The Z4 also keeps its classic roadster proportions, with a long hood, short overhangs, and strong shoulders. However, the car's styling has been modernized with new integrated LED indicators on its flanks as well as on the head and tail-lamps.
The new car is slightly larger outside than its predecessor, offering significantly more comfort and storage. The new car is 5.8in longer, 0.4in wider, and 0.3in lower than the outgoing model. The wheelbase has also grown 0.1in to measure 98.8in from axle to axle.
Two powertrains will be available at the car’s North America launch: a 300hp (224kW) twin-turbocharged 3.0L six wearing the new sDrive35i badge, and a 255hp (190kW) naturally aspirated version of the same engine in the sDrive30i model.
What’s most impressive is the torque characteristics of the turbocharged mill, which maintains its peak levels of 300lb-ft through a broad rev range from 1,400 to 5,000rpm. This allows the car to accelerate from 0-60mph in 5.0 seconds flat and reach an electronically controlled top speed of 150mph when equipped with an optional sport pack. The 0-60mph acceleration time for the sDrive30i, meanwhile, is 5.6 seconds.
While both models are available with a manual six-speed gearbox, the Z4 sDrive35i is available also with a dual-clutch sport automatic transmission featuring seven gears. The six-speed sport automatic is available on the Z4 sDrive30i. Both sport automatic transmissions feature steering wheel-mounted paddle shifters.
The sport automatic gives the driver the choice of either automatic (Program D) or manual gear selection. If desired, the driver may shift gears manually by means of paddles on the steering wheel. Featuring Dynamic Drive Control as standard, drivers will also be able to choose between three drivetrain and suspension settings at the touch of a button. The Z4 also features an electronic rear brake management system, which is used to simulate a limited slip differential for stronger acceleration in turns.
Opting for the Sport Package with Adaptive M Suspension and Electronic Damping Control allows the driver a number of extra controls. In addition to changing damper forces on the Adaptive M Suspension, DDC also conditions the responses of the gas pedal, the power steering, and the response thresholds of Dynamic Stability Control. This is done by choosing either ‘Normal’, ‘Sport’, or ‘Sport+’ modes.
Both models come as standard on 17in light-alloy wheels with runflat tires and a tire pressure monitoring system.
Once again BMW’s EfficientDynamics technologies serve to provide a balance between performance and fuel efficiency. Some of the highlights include on-demand management and control of the car’s accessory drives, a variable oil pump, intelligent lightweight technology, and optimized aerodynamics.
Inside, the car comes with Kansas leather in a choice of three colors, plus optional Ivory White Nappa leather trim as part of the Exclusive Ivory White Leather Package. The entire range of paintwork colors available on the new Z4 is made up of no less than nine color tones including Orion Silver metallic exclusive to the Roadster.
Also included for the first time in the Roadster is BMW’s latest generation iDrive system, which is now integrated with the navigation system. The system itself is made up of a Controller on the center console and a folding, high-resolution 8.8in display screen on the instrument panel. Pressing the direct selection buttons on the newly configured Controller, the user is able to spontaneously change to the CD, radio, telephone and navigation functions. Navigation data is stored on an 80GB hard drive that has 15GB of storage space available for music.
The new Z4 will be built at BMW’s Regensburg plant in Germany alongside the 3-Series and 1-Series models. This is because the American Spartanburg plant, where the former model was built, is concentrating from now on entirely on the production of BMW’s X models.