There’s more to the 2006 BMW Z4 M Roadster than just speed.
When the Z4 was introduced at the 2006 Detroit Auto Show, the German automaker decided to launch the entire lineup. At the same time that BMW introduced an updated, newly powered Z4 Roadster Series, the Bavarian automaker also introduces a BMW M version of this spirited 2-seater: the M Roadster, which takes the Z4's inherent sportiness to an even higher level of thoroughbred performance and driving pleasure.
BMW considered an M version of the Z4 Roadster when it was introduced earlier in the 2003 model year. The Z4 Series had two models back then, as it does now, both powered by regular-production BMW 6-cylinder engines. Now, in 2006, the decision has been made: alongside the now-improved regular-production Z4s (powered by BMW's new magnesium/aluminum Valvetronic 6-cylinder engine), a new M Roadster makes its debut, with production starting in January at BMW's Spartanburg, South Carolina factory.
BMW combines the advanced sports-roadster concept of the Z4 with a version of the BMW M 6-cylinder engine that is even more powerful than the previous M Roadster – plus a slew of new BMW and BMW M developments in suspension, steering, brakes, stability systems, safety features, and, not to be overlooked, luxury and convenience features. In a nutshell, the new M Roadster is a masterful fusion of ultimate BMW M performance, cutting-edge technology, and lavish luxury.
Statistically, the results are stunning: the internally designated S54 engine produces 330 horsepower at a high-revving 7,900 rpm and propels the 3200-pound Roadster to 60 mph in 4.9 seconds. The top speed is electronically limited to 155 mph; enthusiasts will speculate about what the top speed might be without the limiter, but BMW makes no claim in this regard.
Unlike other 3 Series engines that use lighter materials for their block and cylinder head, the S54 uses a cast-iron block with an aluminum head to achieve the engine's 3.2-liter displacement without lengthening the block.
The bore and stroke of this engine are 87.0 x 91.0 mm, which are both larger than the dimensions of BMW's 3-liter engines. However, the M3's induction, combustion, and exhaust engineering, as well as its execution as a high-rpm engine, play larger roles than increased displacement in the 75-hp increase over the most powerful regular-production 6-cylinder engine. A cylinder head that could be described as "exotic" takes center stage here.
The S54 engine continues an important BMW M tradition by having a separate throttle for each cylinder. These are much closer to the cylinders than a single throttle can be, bringing atmospheric pressure almost directly to the cylinder. The "lag time" inherent in airflow into the cylinders is thus greatly reduced, and the engine can respond to throttle movements more quickly.
Some parts of the BMW Z4 M Roadster were shared with other Z4 Roadsters, but not all. On the outside, the front bumper is different, with larger air intakes to keep the brakes and engine cool. The front fenders have been redesigned on the side. The same was true in the back, where the four exhausts were included as standard equipment.
The new sport-bucket seats inside assured the car's occupants that it meant business, and they provided excellent lateral support while cornering. Some M-specific badges could be found on the instrument cluster. The most significant changes to the car were made underneath. The M-version, unlike the rest of the lineup, had hydraulic power steering.
The fully automatic soft-top comes standard in three colors and includes an interior lining for enhanced weather protection. The rear window is made of glass and has heating. The M Roadster, like the Z4, has a variable storage compartment for the soft-top, which allows for more trunk space when the top is up; however, the M's trunk has about 3/4 of a cubic foot less volume than the Z4 Roadster because the M Mobility System and its battery are carried within the trunk space.
The M logo (in its three colors) is displayed in a large, attractive format on the doorsill trims. Once inside the M cockpit, the driver and passenger are surrounded by a distinctively sporty, high-quality environment that combines BMW M's lavish luxury with typical BMW functional design. M sport seats are made of premium Nappa leather and feature embossed M logos on the headrests (manual or power).
The door panels, console arm-pad, knee-pads, handbrake grip, and shift knob are also made of leather. Trim materials are unique: The largest areas (across the dash and center console) are finished in a sporty-technical Aluminum Hexagon surface, with pearl-gloss galvanic trim on the climate controls, interior door knobs and pulls, as well as the "tubes" into which the main instruments are recessed. The M comes standard with automatic climate control, and its rotary knobs have new rubber touch surfaces that improve their tactile feel.
Every aspect of the suspension tuning – damping, spring rates, anti-roll bars – is noticeably firmer than on the Z4, even on Z4s equipped with the optional sport suspension. All of this adds up to a nimble little roadster with cheetah instincts and reflexes. The turn-in process is quick and precise. Even on rough surfaces, the beefy steering wheel transmits detailed road information to the driver's hands without a hint of kickback.
The flow of sensory data from the helm is supplemented by sensations from the operator's visceral regions. The shifter for the ZF six-speed manual gearbox (the previous M roadster had a five-speed) is exceptionally crisp. The brake and throttle pedals are perfectly positioned for heel-and-toe maneuvering, and the bucket seats keep the driver (and passenger) firmly anchored during hard cornering.
Here, there's a strong sense of car-and-driver connection, and the Bimmer's balance is exceptional. When compared to the M3, its shorter wheelbase (by 9.2 inches) makes it feel jittery, but once accustomed to the quicker responses, the driver quickly appreciates the faster footwork. The dynamic stability-control system's threshold is high, so turning it off unless you're racing for the fastest time at an autocross is pointless.
The braking performance is excellent. This was already a strong suit in the previous M roadster, but it's even stronger in the new one. Massive cross-drilled, vented rotors (13.6 inches front, 12.9 inches rear) produce 152-foot stopping distances from 70 mph, which is 10 feet better than the old M roadster and very close to race-car braking.
Sources: AutoEvolution, TopSpeed, CarAndDriver
Hey there, I’m Wyse and I’ve been churning out stellar automotive articles for over three years. HotCars my domain and I’m looking to stake a major claim. Ciao!
- Virtual Delivery
- Human Capital
- Assurance Services
- Research & Benchmarking
- Innovation Solutions
- Financial Solutions
- Private Sector
- Retail & Consumer Products
- Real Estate & Construction
- Private Equity
- Natural Resources
- Manufacturing & Distribution
- Life Sciences
- Industry 4.0
- Government Contracting
- Gaming, Hospitality & Leisure
- Financial Institutions & Specialty Finance
- Assest management
- Public Sector
- Third Sector
- Private Sector
- About Us
- Industry Updates