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The BMW Z4 enters the 2009 model year with completely restyled looks and a foldable hardtop roof.
The new BMW Z4 is slightly larger externally than its predecessor, at the same time offering significantly more interior space and a lot more trunk space. The new Z4 Roadster is 5.8 inches longer, 0.4 inches wider, and 0.3 inches lower than its predecessor. Apart from improved all-round visibility, the interior offers greater headroom, extra shoulder room, and more elbow freedom. The door opening, increased in size by 1.02 inches, allows even more convenient access with the roof closed.
The new BMW Z4 is offered with two inline-6 engines displacing 3.0 liters: 300 hp in the BMW Z4 sDrive35i and 255 hp in the BMW Z4 sDrive30i. 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.
Exterior
The new BMW Z4 takes on the classic look of the roadster in modern, flowing lines. The car’s proportions are born out by the long and low-slung engine compartment lid, short overhangs, the long wheelbase, and large wheels, as well as the low seating position near the rear axle.
The front view features a large, upright BMW kidney grille, wide air intake, and the dual round headlights, typical of the BMW brand. The side view is dominated by the dynamic flow of the car’s shoulder line connecting the front and rear wheel arches and accentuating the stretched, athletic look of the Roadster. The horizontal orientation of the car’s lines and surfaces at the rear, in turn, emphasizes the sheer width of the new BMW Z4. Further characteristics are the extra-large hood extending far over the wheel arches, the black A-pillars, the gills at the side with their integrated LED direction indicators, as well as the slender rear fixtures with three-dimensional LED-fed rows of light.
The new BMW Z4 is the first BMW roadster to feature a fully retractable hardtop. This two-piece lightweight aluminum shell opens and closes at the touch of a button within 20 seconds. The compact packaging of the folding roof enables the Z4 Roadster to retain the characteristic, slender proportions of its predecessor. Large windows and the high-quality roof lining give the hardtop a light look. Compared with the predecessor, the side windows are 40% larger, the see-through area in the rear window 52% larger, and all-round visibility increased by 14% over the previous generation. The glass rear window in the hardtop is equipped with an electric defroster and the four side windows of the new BMW Z4 may be lowered individually. The higher roofline and larger door openings allow easier and more convenient access with the roof closed.
The retractable roof may be operated either by a switch in the center console or by remote control key fob when equipped with optional Comfort Access. Comfort Access also allows convenient loading and unloading of the luggage compartment with the roof open. To provide access to the luggage compartment in this case, the open hardtop is moved to an interim position facilitating the removal of large objects.
The roof compartment and the luggage compartment are separated from one another by a moveable partition, which may be folded up to increase luggage space, if the roof remains closed. Using the optional through-loading system to the passenger compartment, the Z4 is able to accommodate a 46-inch full-size golf bag. When the roof is closed the luggage compartment easily accommodates up to four crates of large bottles or – when using the through-loading system – two 46-inch golf bags.
Various other storage compartments are designed into the interior. The 2009 BMW Z4 offers storage trays in the center console, a 10-liter glove box, hinged compartments in the doors, and additional space behind the seats. Included with the Cold Weather Package is a storage package that provides an even wider range of storage and loading functions, with fastening nets on the rear panels of the seats and in the passenger’s footwell, lashing belts in the luggage compartment, as well as a storage box in the bulkhead leading to the luggage compartment.
An optional through-loading system together with a transport bag ensures even greater versatility, allowing the user to load slender items such as golf bags or two pairs of skis measuring up to 67" in length.
Interior
The new BMW Z4 is equipped as standard with air conditioning and seven blower stages. Optional automatic climate control allows separate temperature selection on the driver’s and passenger’s side, individual, automatic temperature control in five stages of intensity, and manual adjustment of air stratification. With the roof open, automatic climate control includes convertible mode.
Like BMW’s Convertibles, the leather in the new Roadster incorporates Sun Reflective Technology. A special, highly innovative type of leather on the seats, interior panels, and steering wheel that significantly reduces the heat effect of bright sunshine: Treatment of the leather in Sun Reflective Technology serves to integrate special color pigments into the material to reflect infrared radiation in the sunlight. sDrive35i models come standard with leather seat-upholstery.
The CD player fitted as regular series equipment also serves to play music files in the MP3 format. The optional premium hi-fi system comes with up to 14 speakers and two additional subwoofers, with amplifier output of up to 650 watts. A standard AUX-In port is provided, allowing the integration of various external MP3 players. A 6-disc CD/DVD changer in the glove compartment is also available.
The 2009 BMW Z4 is the first BMW Roadster to feature the iDrive control system as part of its optional navigation system. In the new Z4 the iDrive serves to activate all entertainment, information, navigation and telecommunication functions.
The system itself is made up of a Controller on the center console and a folding, high-resolution Control Display on the instrument panel, allowing the driver to intuitively and safely mastermind all available functions.
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. The range of direct selection buttons has now been rounded off by the three MENU, BACK and OPTION command buttons, and programmable favorite buttons in the instrument panel allow the user to save and directly select radio stations, telephone numbers and navigation destinations, and other menu items available directly through iDrive.
Measuring 8.8 inches in size, the high-resolution Control Display with its resolution of 1,280 x 480 pixels offers excellent clarity in presenting graphics or pages from the internet. A picture of the Controller shown in the Control Display gives the driver greater and clearer orientation in choosing the next step in the operating process.
Using the navigation system is even easier thanks to iDrive. Full-screen map presentation, for example, offers an incomparably detailed overview of the region in which the driver is currently traveling. As an alternative the Control Display also offers an assistance window presenting further highlights and maps independent of the main map. With navigation data saved on an 80 GB hard disc installed in the car, access times are faster than before. And at the same time the hard disc may also be used as a 15 GB music archive.
A Bluetooth interface is available in conjunction with optional BMW Assist to offer greater safety and convenience for making telephone calls while driving. To fully integrate the latest smartphones in the car, the new BMW Z4 is also available with a smart phone integration option.
Drivetrain
The 2009 BMW Z4 is launched exclusively with inline-6 engines. These unique engines exhibit refinement and fast-revving response typical of a BMW six-cylinder, offering an unparalleled balance of performance and fuel efficiency, thanks to the BMW EfficientDynamics engineering strategy.
The most dynamic version of the 2009 BMW Z4 comes with an 3-liter inline-6 engine featuring twin turbochargers, High Precision Injection, and an all-aluminum crankcase. High Precision Injection is a key element in the Z4’s efficient performance. Injecting fuel directly into the combustion chamber offers a cooling effect allowing a higher compression ratio and optimized combustion efficiency. This second generation of direct gasoline injection developed by BMW ensures significant benefits in fuel efficiency without restricting the dynamic qualities of the engine. The use of two turbochargers (each supplying three cylinders) ensures responsiveness unequalled for gasoline engines, achieving peak torque of 300 lb-ft at 1,400 rpm and maintaining this high level of torque throughout a broad rev range up to 5,000 rpm. Maximum output of 300 hp comes at 5,800 rpm, which BMW claims will accelerate the Z4 from 0-60 mph in 5.1 seconds.
The standard engine in the 2009 BMW Z4 is a naturally-aspirated 3-liter 6-cylinder, which weights just 355 lb thanks to its composite magnesium/aluminum crankcase, cylinder head cover made of a special synthetic material and lightweight camshafts with aluminum VANOS control unit. While BMW’s VALVETRONIC engine management controls valve stroke on the intake valves, double-VANOS varies the angle of the intake and outlet valves in an infinite process. This allows particularly efficient use of fuel, providing a “beefy” torque curve and giving the engine instant response. The engine in the BMW Z4 sDrive30i develops a maximum output of 255 hp at 6,600 rpm. Maximum torque of 220 lb-ft comes at just 2,600 rpm.
All variants of the new BMW Z4 come as standard with a 6-speed manual gearbox. Optional on the normally aspirated models is a 6-speed automatic with paddle shifters, while the turbo models can be ordered with a 7-speed double clutch transmission. Based on the M DCT transmission introduced in the BMW M3, this 7-speed gearbox ensures faster acceleration and extra performance in comparison with the 6-speed manual gearbox, while providing the comfort features of an automatic transmission. The 7-speed double-clutch sport automatic shifts gears without the slightest interruption of power.
Technology
Rear-wheel drive, excellent weight distribution, a long wheelbase, and a low center of gravity on the roadster create ideal conditions for superb agility. Featuring traditional spring-struts, a “double-jointed” front suspension made largely of aluminum, and a constant-geometry rear axle, the new Z4 comes with proven suspension concepts.
Dynamic Drive Control (DDC) allows the driver of the 2009 BMW Z4 to choose the drive characteristics of the car. 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. And if the car is fitted with either sport automatic transmission, the adaptive gearshift logarithms are adjusted. The driver operates Dynamic Drive Control via a button on the center console next to the gear selector. By pressing the button, s/he is able to choose from the NORMAL, SPORT and SPORT+ modes, thus activating a pre-configured, perfectly balanced set-up. The SPORT mode, for example, offers more-direct steering behavior and a more-direct response to the gas pedal. The SPORT+ mode, in turn, serves additionally to activate the Dynamic Traction Control mode of DSC, intentionally allowing slight wheelspin and thus enabling the driver to take a bend in a controlled drift.
The new Z4 comes with new high-performance brakes with a diameter of 11.8 inch on both ends. At the same time the BMW Z4 is the first car in its segment to feature an electrical parking brake activated and released by a button on the center console.
Both versions of the new BMW Z4 come as standard on 17-inch light-alloy rims and with runflat tires as well as a Tire Pressure Monitor.
BMW’s standard Dynamic Stability Control (DSC) serves not only to activate the ABS brakes and ensure stability on slippery surfaces by activating the brakes or reducing engine power, but also comprises other functions such as Brake Drying and Brake Standby as well as a Start-Off Assistant. Acting in a similar way to a mechanical limited slip differential, DSC electronic rear brake management is used to simulate a limited slip differential for stronger acceleration in turns. Activating Dynamic Traction Control at the touch of a button, the driver is able to raise the response thresholds for intervention by the DSC, thus enjoying the option, for example, to set off on loose snow with the drive wheels slightly spinning. And when desired, the driver is also able to deactivate DSC altogether (ABS remains active).
An optional Sport Package features an Adaptive M Suspension with Electronic Damping Control. A central control unit varies the “compression” and “rebound” stages on the four twin-sleeve gas pressure dampers to provide optimum response at all times. The response time is so fast that a signal coming from a front wheel crossing a hole in the road reaches and re-adjusts the rear dampers even before the rear wheels reach the same uneven road surface.