2009 BMW Z4 Roadster Preview

Introduction

The first popular modern incarnation of BMW's roadster appeared as the Z3 in 1996 (the Z8 was a hand-built, limited-production vehicle which had appeared a few years earlier). While open motoring was a new experience to mainstream BMW buyers, the 2-seat droptop was offered with a 1.8-liter 4-cylinder engine that did little to stir the soul. Several larger engines appeared in subsequent years (including an M Roadster in 1998), and a fixed-roof Coupe joined the lineup in 1999. Both Z3 models were replaced by the all-new Z4 Roadster/Coupe models in 2003 and 2006, respectively. Larger, stronger and more refined than their predecessors, BMW's Z4 models were offered with a choice of 6-cylinder powerplants and manual, automatic or Sequential Manual Gearbox (SMG) transmissions.

The 2009 model year marks a significant change in BMW's Z4 lineup with the debut of an all-new model at the North American International Auto Show. It is a retractable hardtop convertible-a first for BMW's roadster. The new roof allows the redesigned 2009 Z4 Roadster to effectively replace both the convertible and coupe models from the previous generation. Its near-perfect weight balance, two available 6-cylinder engines (one with two turbochargers), and choice between three transmissions only adds to the Z4's appeal.

Design

All 2009 BMW Z4 Roadster models are fitted with the same retractable hardtop roof. The two-piece electrohydraulic top is manufactured with a lightweight aluminum shell construction and a heated glass rear window, and BMW says it will completely open or close within 20 seconds at the touch of a button. When open, the roof panels fold down nearly flush with the rest of the bodywork to retain BMW's low-slung rear-end design. When closed, the fully lined and insulated roof duplicates the comfort, quietness and outward visibility associated with a fixed-roof coupe, BMW says.

Like the outgoing model, the new Z4 Roadster's styling features a long hood, large wheel arches, long wheelbase, and small overhangs-the styling is unmistakably BMW. The interior has been revamped with increased head and elbow room, and higher-quality materials throughout the cabin. There is a wide range of storage options throughout the cabin, including a spacious crosswise storage compartment behind the two seats. The instrumentation is typical BMW with a large oval speedometer and tachometer set immediately behind the 3-spoke steering wheel. Five more round clusters across the dash contain the start/stop button and auxiliary cabin climate controls. The audio system and its associated controls are found in the middle of the dashboard, just ahead of the transmission selector. The 8.8-inch high-resolution iDrive screen (also used by the optional navigation system) rises out of its stored and protected position in the center of the dashboard. Window controls are on the driver's door.

Model Lineup

There are two different 2009 BMW Z4 Roadster models: Z4 sDrive30i and Z4 sDrive35i. The "30" in the nomenclature refers to models with the normally aspirated 3.0-liter 6-cylinder powerplant, while the "35" distinguishes the 3.0-liter, twin-turbo 6-cylinder models. The Z4 sDrive30i is available with either a manual 6-speed transmission or a 6-speed automatic transmission. The more powerful Z4 sDrive35i may be optioned with a 6-speed manual or a 7-speed dual-clutch sport automatic transmission.

Hardware

There are two 6-cylinder engines offered in the 2009 BMW Z4 Roadster. While each displaces 3.0 liters, the powerplants are only remotely related. The Z4 sDrive30i features a magnesium/aluminum 3.0-liter, inline 6-cylinder engine rated at 255 hp at 6600 rpm and 220 lb.-ft. of torque at 2600 rpm. It is available with a 6-speed manual transmission, or a 6-speed Steptronic automatic transmission with shift paddles. According to BMW, the Z4 sDrive30i sprints to 60 mph in 5.6 seconds with a 6-speed manual transmission (6.0 seconds with the automatic).

The performance-oriented Z4 sDrive35i features an all-aluminum (with cast iron cylinder liners) 3.0-liter twin-turbocharged powerplant with direct fuel injection. It is rated at 300 hp at 5800 rpm and 300 lb.-ft. of torque at 1400 rpm. According to BMW, the Z4 sDrive35i will hit 60 mph in just 5.1 seconds with the standard 6-speed manual transmission. Opt for the electronically controlled 7-speed dual-clutch automatic ("Sport Auto 7-Speed") with shift paddles and the Z4 will rocket to 60 mph in 5 seconds flat. All Z4 models without the optional Sport package are electronically limited to 130 mph (the limit is bumped to 150 mph on vehicles equipped with the Sport package).

The rear-wheel-drive 2009 BMW Z4 features a lightweight independent aluminum suspension on all four corners (an Adaptive M Suspension with electronic damping control is optional). An electric power steering system enhances precision while reducing fuel consumption, BMW says, also claiming that the new high-performance brakes reduce stopping distances and slow pad wear. The Z4 is also the first car in its segment to offer an electric parking brake activated by a switch in the center console, according to BMW.

Safety

In addition to 3-point safety belts with new belt tightening technology, BMW equips all 2009 Z4 models with driver and passenger air bags equipped with advanced technology dual-threshold and dual-stage deployment. Head/thorax air bags are integrated into the front and side of the seat backrests. The A-pillars (around the windshield) have been massively reinforced and there are fixed roll bars behind each of the passenger seats. All Z4 models feature run-flat tires and a tire-pressure-monitoring system. Standard active safety features in every BMW Z4 include anti-lock brakes (ABS), Dynamic Stability Control (DSC) with Brake Fade Compensation, Start-off Assistant, Brake Drying, Dynamic Traction Control (DTC), and Dynamic Brake Control.

Technology

Setting a new standard for convertibles, the 2009 BMW Z4 offers an innovative roof that allows unobstructed open-top motoring, yet seals tightly when closed to protect occupants from wind and weather. The aluminum roof offers expansive windows that are 40 percent larger on the side, and 52 percent larger in the rear than the windows on its predecessor, according to BMW. The overall increased visibility, and the extra-light color interior lining, add to the roomier ambience within the cabin, the manufacturer says. The roof, and the four powered windows, may all be dropped by either a switch in the center console or via the remote control key fob (when equipped with the optional comfort access system).

Like the BMW 3 Series convertible, the droptop Z4 Roadster also incorporates Sun Reflective Technology in its leather upholstery. The technology uses special highly-reflective leather on the seats, interior panels and steering wheel that BMW says will significantly reduce the heating effect of bright sunshine on those surfaces.