2004 BMW Z4 Roadster - In Depth

BMW Z4 Roadster

Refinements for its second model year

October 13, 2003 4:10 PM
Filed Under: BMW

Press Release

2004 BMW Z4 Roadster - In Depth

Product highlights

Z4 roadster 2.5i & Z4 roadster 3.0i
General
What's new for 2004
Performance & efficiency
Handling, ride & braking
Exterior & aerodynamics
Ergonomics, luxury & convenience
Safety & security
Factory-installed options
BMW Center-installed accessories

Z4 3.0i

In addition to features listed for the Series, the 3.0i adds or substitutes:
Performance & efficiency
Handling, ride & braking
Exterior & aerodynamics
Ergonomics, luxury & convenience
Factory options
______________________

2004 BMW Z4 Roadster – In Depth

After a successful launch, refinements for its second model year
When the Z4 roadster was introduced a year ago, it was a significant leap forward from its highly successful Z3 predecessor. Indeed, the Z4’s debut was much more than just “successor replaces predecessor,� for the new Z4 roadster put BMW in a more elevated, sophisticated segment of the roadster market. To paint the broad strokes: Built on a longer wheelbase than that of the Z3, the Z4 is also wider and longer – while employing advanced engineering to keep any associated weight increase to a minimum. More to the point, the Z4 expresses a traditional concept – that of the two-seat sport roadster – in utterly new terms of unique design, contemporary engineering and comprehensive features. The Z4 places BMW squarely in the field of sophisticated, full-featured sport roadsters. It comes exclusively with 6-cylinder power and offers a choice of four transmission types. Its chassis engineering is new, encompassing multi-link rear suspension, standard run-flat tires and wheel/tire diameters up to 18 inches. The Z4 offers amenities and options never before seen in a regular-production BMW roadster. Safety engineering and features have been further developed. As was the Z3, the Z4 Series is produced at BMW’s Spartanburg, South Carolina factory, which employs the most advanced production equipment and processes and serves all international markets for the Z4. Two models are offered: the Z4 roadster 2.5i at $33,895 base price including destination; and the higher-performing, more extensively equipped Z4 roadster 3.0i at $41,045. As with all other 2004 BMWs, these prices include BMW Full Maintenance for 4 years or 50,000 miles.

What’s new for 2004

The ’04 Z4 roadsters are improved in detail for the ’04 model year:
The BMW Roadster Tradition
As new as it is, the Z4 represents a long-standing BMW tradition. The roadster lineage begins in 1935 with the 315/1 and 319/1, two versions of an energetic little two-seater powered by engines that were small, yet had 6 cylinders. (Even then, engine smoothness and sound were BMW priorities.) In 1936, the tradition became legend with the 328 roadster, which began as a successful racing car, went on to become a beloved sports car, and finally became one of the great collectibles of its era.
Another great BMW classic was the 507, of which only about 250 were built in the mid- to late 1950s. Today, this stunningly designed, V8-powered roadster commands high six-figure prices at collector-car auctions. Elvis Presley owned one while stationed in Germany with the U.S. military.
Virtually unknown in America, yet also important to BMW’s roadster lineage, was the Z1 – conceptually amazing, with its fiberglass body and electrically retracting doors. The Z1 was expensive, built in small numbers, and only offered overseas.
In 1996, BMW introduced a roadster that would be accessible to many more customers: the Z3. The Z3 was an instant, international success. Over its seven-year production span, it evolved from a single 4-cylinder model to a line of 6-cylinder roadsters and a coupe. It will be remembered as a relatively simple, fun-to-drive machine of typically high BMW quality.
With its design inspired by the classic 507, the Z8 made its debut in 2000 as BMW’s best-performing, leading-edge roadster. It continues to command the respect of enthusiasts, owners, and the media. The new Z4 continues this successful roadster heritage by delivering BMW design and technological innovation in a new roadster sure to captivate the hearts of enthusiasts everywhere.

The Look:

Roadster Tradition and Future-Oriented Design come Together
“Every BMW design rests on two indispensable pillars: tradition and the future,� says Katharina Mack of BMW Design. Perhaps more than any other factor, it is the proportions that define a roadster. Traditionally, a roadster – Historically, a roadster focuses on pure driving pleasure, the interaction of driver and machine and road. “Wind in the face� when the roadster’s softtop is lowered is an essential element of this highly active driving experience. The Z4 expresses traditional roadster proportions with an ultra-contemporary design. Its surface development features highly three-dimensional forms and interplays between convex and concave. Highlights of the design include:

Aerodynamics

Outstanding for an open-bodied vehicle
It is far more challenging to achieve efficient aerodynamics with an open-body car than with a closed one; yet BMW’s designers and aerodynamicists achieved major progress. With its softtop in place, the Z4 has an aerodynamic drag coefficient (CD ) of just 0.35. And extensive development has minimized drafts around the faces and upper bodies of Z4 occupants when the top is down: In its May ’03 issue, Road & Track reported that “at a constant 75 mph with the side windows down, we found the wind only tugging lightly at our cars.�

2004 BMW Z4 Roadster – In Depth

Smooth, powerful 6-cylinder engines

In a sea of V-6 engines, BMW swims almost solo with its unusual – but in BMW’s opinion superior – inline-6 configuration. The Z4 roadsters are powered by two versions of the M54 6-cylinder engine family; of the 3.0-liter version powering the Z4 3.0i, Automobile Magazine (August ’03) wrote that “Its torquey, 3.0-liter six is always ready to respond.� In addition to its inline six cylinders, this brilliant engine architecture features: With all these elements of engine architecture shared, two versions of this powerplant power the two Z4 models: Z4 2.5i. 2.5-liter, with 184 horsepower and 175 lb.-ft. of torque. This unit delivers 0 to 60 mph in 7.1 sec. (manual trans., BMW AG test results) and achieves the amazing top speed of 146 mph. Its EPA mileage ratings are impressive too: 20 mpg city/28 mpg highway with 5-speed manual transmission, 20/29 with the optional 6-speed Sequential Manual Gearbox (SMG), and fully 21/28 with the available 5-speed automatic. Top speed is 137 mph with the 5-speed, 146 with SMG and 141 with the automatic. Z4 3.0i. 3.0-liter, with 225 hp and 214 lb-ft. of torque. This version is further refined for an even more exciting sound. Motor Trend noted in its May ’03 issue that “It delivers an impressive amount of power, with vibration evident only by its absence…Underway, dual exhaust tips broadcast a turbine-like mechanical growl that’s wired directly to the driver’s right foot.� This engine powers the Z4 3.0i to 60 mph in just 5.9 sec. with the standard 6-speed manual transmission or optional SMG, and reaches 60 mph in only a tick more at 6.0 sec. with automatic (BMW AG test results). Top speed is electronically limited to 155 mph with the manual transmission or SMG; with the automatic it is a “natural� 152 mph. With its manual transmission, the Z4 3.0i earns excellent EPA mileage ratings of 21 mpg city / 29 mpg highway; with SMG the ratings are 20/29 and with automatic 19/27.

5- and 6-speed manual transmissions

While the 2.5i model’s standard transmission is a 5-speed manual, standard in the 3.0i is a 6-speed unit. Weighing no more than the 5-speed, this “gearbox� incorporates refinements for even greater driving pleasure (and BMWs are already known for excellent manual transmissions):

Optional STEPTRONIC

5-speed automatic transmission
Available for both models is the 5-speed STEPTRONIC unit that has garnered repeated praise from auto critics. Like all other current BMW automatics, it incorporates –

“Third way�

The Sequential Manual Gearbox
BMW currently offers two types of Sequential Manual Gearbox (SMG), both of which apply electrohydraulically actuated, electronically or driver-controlled shifting to a 6-speed manual transmission. Available on the super-performance M3 models is the very elaborate DRIVELOGIC version, which offers drivers a total of 11 shift programs. The version offered as optional equipment for Z4 roadsters (and, for ’04, the 3 and 5 Series as well) is engineered for performance, convenience and (above all) driving pleasure; it offers a total of four shift programs: In either mode, the Sport program is selected via a button on the console. There is no clutch pedal. The driver selects the desired operating range (N, R, D, S = Sequential) with a console-mounted selector lever, and can execute manual shifts with that lever or with two “paddles� on the steering wheel. After starting the engine (which requires putting the lever in N and applying the brake pedal), the driver moves the lever to the right; this selects the Sequential mode, in which each tap of the lever or paddle(s) shifts the transmission up or down one gear. Moving the lever to the right toggles the unit to its Drive mode, in which shifts occur without the driver’s intervention. To revert to Sequential shifting, the driver can toggle the lever to the right again (and simply tap it toward “+� for an upshift or “–� for a downshift) or toggle one of the steering-wheel-mounted shift paddles. By pulling either steering wheel-mounted paddle, an upshift is executed. Pushing either paddle with your thumb produces a smooth downshift. In either the Drive or the Sequential mode, an instrument-cluster display indicates the gear currently engaged. In Drive, a “D� is displayed next to the gear. When the Sport program is activated, an orange indicator light next to the Sport button illuminates. Though SMG does offer automated shifting, it is not meant to serve as a conventional automatic transmission; that role is played by the also available STEPTRONIC automatic. Just as with a manual transmission, power is interrupted for shifts – though in hard, performance-oriented driving the shifts can be stunningly quick. SMG’s appeal lies in these considerations:

Z4 running gear

This roadster is glued to the road
The Z4 raises enthusiasts’ expectations of how a sports car should handle. Starting with a brand-new body/chassis structure, BMW chassis engineers developed a sports-car platform that is almost literally glued to the road. The basis for this remarkable platform is a body/chassis structure with exceptional stiffness for a roadster; it achieves 21 Hertz – truly outstanding for a roadster, and close to the 25-26 Hz of today’s BMW sedans. A number of specific features contribute to this rigidity: In general terms, the Z4 suspension system applies concepts familiar from the 3 Series. Now, imagine a further developed system in vehicles almost 300 pounds lighter and with a significantly lower center of gravity, and you get an idea of the Z4’s potential. Here are the particulars: Strut-type front suspension. with notable features: Central Link rear suspension, a multi-link concept. The Central Link from which the system derives its name is a large, curved longitudinal arm, pivoted directly ahead of the rear wheel’s vertical and horizontal centerpoint on a large rubber bushing of highly sophisticated design. Each wheel also has an upper and a lower lateral arm, for a total of three links per wheel. The system contributes to remarkable handling and riding comfort, yet is simpler than many multi-link concepts. Salient features include: Overall suspension calibration. To underscore the Z4’s sporting nature, relatively firm springs, shock absorbers and anti-roll (stabilizer) bars have been adapted. This means a firm ride and very “flat� cornering. Because the standard suspension calibration is inherently sporty and the standard run-flat performance tires are relatively stiff, the available sport suspension (included in each model’s Sport Package) does not employ firmer springs, shock absorbers and anti-roll bars as is customary with BMW sport suspension. Instead, its only difference is a 15-mm (0.6-in.) lower ride height. Every Sport Package-equipped Z4 comes with Dynamic Driving Control, which provides a Sport button on the console that selects – ______________________
1 – VANOS = VAriable NOckenwellen Steuerung = variable camshaft control, or variable valve timing.
2 – Hertz, or cycles per second, quantifies a structure’s rigidity in terms of its natural frequency of vibration when set into motion by some disturbance or input. Generally, the higher this frequency, the more rigid the structure.

2004 BMW Z4 Roadster – In Depth

Electric power steering: innovation with significant benefits

The Z4 incorporates an electric power steering system: the steering is assisted by an electric servo motor rather than the conventional hydraulic pump. Among the benefits of this feature are: The servo motor applies its assist to the upper portion of the steering column; its control electronics are in a housing mounted directly to the motor.

Generously dimensioned brakes

The Z4 3.0i gets ventilated rear discs, and both models have larger-diameter rear discs than those of their Z3 predecessor. Equipment is as follows: BMW has applied two refinements to the handbrake mechanism. One is a self-adjusting actuating cable, reducing the need for periodic adjustment; the other is a newly designed cable linkage that ensures equal handbrake force on both rear wheels.

Run-flat tires, standard

Every Z4 comes standard with BMW’s Run-Flat Combination (RFC), an important step forward in personal safety, convenience and in-vehicle space utilization. The system consists of self-supporting tires, special wheel rims and a Flat Tire Monitor. The tires have special sidewalls that include specific inserts and highly heat-resistant rubber compounds. These features allow a deflated tire to maintain its essential shape and guidance characteristics for a considerable distance. While maintaining the handling and safety standards of high-performance tires, the RFC system offers these advantages:
No roadside tire changes. It will be seldom, if ever, necessary to stop and change a damaged tire. When confronted with a flat (a condition revealed to the driver by the Flat Tire Monitor), the driver can continue on for up to 90 miles at speeds up to 50 mph until reaching a safe and/or convenient place to have the tire repaired or replaced. Tire stays on rim, thanks to specially developed wheel rims.
Stability systems remain functional. All Dynamic Stability Control functions remain fully in effect, even with a deflated tire.
Increased trunk space. With RFC, no spare is needed, so the trunk can be larger.
Weight savings. The weight of a spare tire is eliminated.

Wheel and tire specifics

combinations in 16, 17- and 18-inch sizes
Each Z4 model comes standard with beefy standard wheels and tires, and offers an upgrade as part of its optional Sport Package. All wheel designs are specific to Z4s; all tires are performance-type.
2.5i standard. Ultra-open Cross Spoke wheels are dimensioned 16 x 7.0 and carry 225/50R-16 V-rated tires. These wheels are especially light, enhancing the low unsprung weight promoted by aluminum suspension components.
2.5i Sport Package. 17 x 8.0 Turbine wheels wear 225/45R-17 W-rated tires for this upgraded equipment.
3.0i standard. Wheel and tire sizes and the tires’ speed rating are equivalent to those of the 2.5i Sport Package; the wheel design is Twin Spoke.
3.0i Sport Package. In this ultimate Z4 wheel and tire combination, handsome Ellipsoid wheels are sized 18 x 8.0 front / 18 x 8.5 rear and carry 225/40R-18 front / 255/35R-18 rear W-rated tires.
Expert critics have discovered for themselves the results of BMW’s careful development of the Z4’s road (and racetrack) manners:

2004 BMW Z4 Roadster – In Depth

Z4 cockpit

Contemporary design, function and materials
The Z4’s cockpit exudes fresh and exciting design, and offers many new features as well as a wide selection of appealing materials. Many of its features, both standard and optional, are making their first appearance in a BMW roadster. Interior design is carefully harmonized with the bold exterior design. A pronounced “T� theme defines the dash and center console; here too, the fascinating interplay of convex and concave appears in the contours, particularly the large, full-width panel that frames the audio system, center air outlets and primary driving controls. Instrument design and configuration are completely new. Unique Z4 surface interplay is seen yet again on the interior door pulls, which make transitions from convex to concave and back again as they sweep upward from the armrests; even the interior door handles are distinctive. Optimum seat design and construction. Sport seats are standard, with prominent side bolsters to help support the occupants laterally during sporty driving. Six-way manual adjustment is standard; 8-way power adjustment and driver’s-seat memory are optional. Tilt/telescopic steering wheel, adjustable 30 mm/1.2 in. for tilt and reach. For ’04, the multi-function steering wheel incorporates the functionality of audio controls for added convenience. Attractive, informative instrument cluster. The twin visors, with speedometer at left and tachometer at right, is traditional; everything else is fresh and unique to the Z4. Various information and warning displays appear in a window in the speedometer dial, on the speedometer and tachometer dials themselves, and in the space between the two.

Upholstery and trim

Four available interior themes
Between the two models, the Z4 offers four interior upholstery schemes and various choices of trim materials. All complement the cockpit’s fresh and contemporary design:
Leatherette – 2.5i standard. Black leatherette appears on the seats and door panels; the steering-wheel rim and handbrake grip are in leather. Graphite-finish trim complements the interior.
Active Sport interior – 2.5i optional. With this sporty two-tone option, the seats are in leather and a contemporary synthetic fabric. The large dash trim panel and console trim are brushed aluminum; other trim is as in the standard 2.5i interior. Available in Pearl Gray/Black or Maldives Blue/Gray.
High Performance leather – 3.0i standard, 2.5i optional. Leather seats, upper door-panel inserts and dash kneepads; brushed-aluminum major trim as in the Active Sport scheme. Available in Black, Beige, Dream Red/Gray and (new for ’04) Dream Red/Black.
Extended High Performance leather – 3.0i optional. This option upgrades the leather and extends it to the windshield frame, sun visors and larger door-panel areas. Available in Black, Beige, Dream Red/Gray and (new for ’04) Dream Red/Black.
Sycamore wood trim – optional both models. Available with all interiors except the leatherette, this elegant wood accents the dash and console.

Well designed soft-top in manual and power versions

The Z4 offers manual and power roadster softtops, the latter optional on both models. Both versions include many advances in function and operational ease: Fully automatic power top. To lower the top, the user simply presses a button. The top unlatches from the header and folds down. Raising the top is also fully automatic; both occur lightning-fast and quietly. “Few convertibles can boast a softtop as easy to raise and lower as the Z4’s,� commented Motor Trend. “When raised, the top is free of flutter and drafts, while the blind spot is minimized with a large glass rear window. The top structure proved tight and draft-free.� The power top includes all features of the standard one, plus a choice of colors: In addition to the standard black, the power top is available in Gray and Dark Beige according to body and interior colors.

Other amenities

Throughout the Z4 cockpit, thoughtful features add convenience and luxury, yet never diminish the Z4s’ innate sportiness. Power side-window sealing system. When a door is opened, its window (if closed) drops slightly. When the door is closed, it rises into the weather seal, for excellent sealing when the windows and top are up. Rain-sensing windshield wipers and auto headlight control. Standard for ’04. Climate control, manual or automatic. The standard climate system features easy-to-adjust controls and a ventilation microfilter. Automatic climate control is a new BMW roadster feature; for details see options and accessories. Audio system, 2.5i standard. A handsomely integrated audio system with single-disc CD player is standard. Its 10-channel amplifier feeds a 3-way front/2-way rear speaker system with a total of 10 speakers. Premium audio system, 3.0i standard/2.5i optional. This premium system offers –

Further development of BMW’s comprehensive safety and security concept

At the core of the Z4 safety concept is the ultra-strong roadster body. Within this protective shell, extensive safety systems, such as Active Knee Protection, form critical elements of the user interface between the Z4 body and its occupants. Features found in all current production vehicles are of course present: The Z4 also incorporates the following:
Optimized Smart Airbags. Both airbags have been further developed to optimize their inflated shape, deployment characteristics, and interaction with surrounding surfaces and components. The driver’s-side airbag is notable for its compactness, fitting into the relatively small center hub of the standard sport steering wheel. Active Knee Protection. Two dedicated airbags are positioned below the dash and ahead of the driver’s and passenger’s knees. Because the airbags are normally in their uninflated state, they reduce the amount of space taken up by the knee protection, and allow very effective fine-tuning of other restraint systems (safety belts and front airbags). New-technology side-impact sensors. By sensing pressure change within the door structure (rather than actual deformation as is conventional), these are able to trigger deployment of the side airbags very early in a side impact, yet minimize the chance of an unwanted deployment. Passenger-airbag de-activation switch. To facilitate carrying a child in an approved infant seat, Z4s are standard-equipped with a disable switch for the passenger-side airbag. The switch requires a key to change over, and activates a “passenger airbag off� indicator on the console. Rollover Protection. Between the reinforced A-pillars/windshield frame and the standard roll bars, the Z4 roadster has what it takes to maintain a “survival space� above its open cockpit. The Z4 was recently awarded a five-star rollover rating by the National Highway Traffic Safety Administration (NHTSA). Out of a total of 21 vehicles tested, ranging from compacts to SUVs, the Z4 roadster was the only vehicle to receive the top honors in this test. ISIS, the Intelligent Safety and Information System. With the goal of tailoring safety systems more precisely to actual impacts, ISIS employs a larger number of sensors than previous systems. Much of the progress on this front is due to faster, more powerful electronics and the use of fiber-optic cables that are not susceptible to extraneous electromagnetic disturbances. System software can be updated over the life of the vehicle; data useful to researchers can be retrieved from accident vehicles.

2004 BMW Z4 Roadster – In Depth

Options and accessories

Numerous possibilities for personalizing
The Z4’s option list offers exciting and numerous ways to suit its owners’ priorities and tastes. An extensive range of Packages, stand-alone options and BMW Center-installed accessories makes it possible to enhance performance, handling, design appeal, luxury and convenience. Premium Package. The 2.5i Package includes: The 3.0i Premium Package omits cruise control and leather (standard). Convenience Package. The 2.5i Package includes: The 3.0i Convenience Package omits Onboard Computer (standard). Sport Package. The 2.5i Package includes: The 3.0i Sport Package omits the fog lights and heated mirrors/washer jets (standard) and adds: Stand-alone options include the following:
5-speed STEPTRONIC automatic transmission, both models.
6-speed Sequential Manual Gearbox (SMG) , both models.
Metallic paint. Optional on both models.
Cruise control. Included in the 2.5i Premium Package, also available as a stand-alone option for that model.
Xenon headlights. Of the four headlights, the outer ones provide Xenon (high-intensity discharge) illumination on low and high beams. The inner beams are used for flash-to-pass and (if activated according to customer preference) Daytime Running Lamps. Auto-leveling of the Xenon lights is included. On the 2.5i, this option requires the foglights option or the Sport Package.
Front foglights. Part of the 2.5i Sport Package and available as a stand-alone option, also includes heated outside mirrors and windshield-washer jets. Standard on the 3.0i.
Fully automatic power top. Included in the Premium Package, also available as a stand-alone option.
Active Sport cloth/leather interior. Available on the 2.5i only.
High Performance leather interior. Standard on 3.0i, included in 2.5i Premium Package but also available as a stand-alone option.
Extended High Performance leather interior. Available on 3.0i only.
Sycamore wood interior trim. Available with all interiors except 2.5i standard leatherette.
Power seats with driver’s-seat memory. Included in Premium Package, or as a stand-alone option (both models).
Heated seats. Optional on both models.
On-board Computer. Part of 2.5i Convenience Package, also available as a stand-alone option. Standard on 3.0i.
BMW On-board Navigation System. Available on both models, requires Convenience Package (2.5i only).
Premium audio system. Stand-alone option for 2.5i, standard on 3.0i.
Hardtop preparation. Readies the vehicle for installation of the accessory hardtop

BMW Assist: new option for ’04

This new system is available as a stand-alone option or part of the Premium Package. The in-vehicle equipment for BMW Assist includes GPS technology, an embedded wireless communication system, and “SOS� and “Wrench� buttons that in the Z4 are located on the center console. Vehicle occupants may request emergency or other services simply by pressing a button; the BMW Assist system then transmits the location and vehicle information to the BMW Assist Response Center. A response specialist will then speak with the occupants to coordinate dispatch, notify emergency contacts on file, and link BMW Roadside Assistance or emergency services as needed and requested. Deployment of an airbag automatically activates BMW Assist. A year’s subscription to BMW Assist is included with the option; after the initial year, the annual fee is $240. In addition to the safety-related benefits, subscribers can call a toll-free 800 number to avail themselves of many BMW Assist Concierge services, from travel planning to dining reservations, shopping assistance and event tickets. Like all current models, each Z4 roadster is covered by BMW’s 4-year/50,000-mile limited warranty and comes with the a 4-year/50,000-mile Full Maintenance Program for customer convenience, peace of mind and economic benefit.
Performance with a conscience
BMW strives to produce its motor vehicles and other products with the utmost attention to environmental compatibility and protection. Integrated into the design and development of BMW automobiles are such criteria as resource efficiency and emission control in production; environmentally responsible selection of materials; recyclability during production and within the vehicle; elimination of CFCs and hazardous materials in production; and continuing research into environmentally friendly automotive power sources. Tangible results of these efforts include the recycling of bumper cladding into other vehicle components; water-based paint color coats and powder clear coats; near-future availability of hydrogen-powered models; and various design and engineering elements that help make BMWs easier to dismantle at the end of their service life. ______________________
3 – Due to low-profile tires, please note: wheels, tires and suspension parts are more susceptible to road hazard and consequential damages.
4 - Requires Sport Package

2004 BMW Z4 Roadster – In Depth

2004 BMW Z4 specifications

2004 BMW Z4 Roadster – In Depth

2004 BMW Z4 features & options 2004 BMW Z4 pricing 2004 BMW Z4 pricing