Engineering:BMW M Roadster

BMW M Roadster
Overview
Manufacturer	BMW
Production	1998–2008
Body and chassis
Class	Roadster Sports car
Layout	FR layout

The BMW M Roadster is the BMW M performance model of the BMW Z3 and BMW Z4 convertibles. It was produced between 1998 and 2002 and again during the 2006-2008 model years. All models were produced in the Greer, South Carolina manufacturing facility, though the complete M engine was imported from Germany.

Z3 M Roadster (1998–2002)

First Generation E36/7 M Roadster
Overview
Manufacturer	BMW
Also called	Z3 M Roadster, MZ3
Production	1998–2002
Assembly	BMW US Manufacturing Company Greer, South Carolina, United States
Designer	Joji Nagashima
Body and chassis
Class	Roadster Sports car
Body style	2-door roadster
Layout	FR layout
Platform	E36/7
Related	BMW Z3
Powertrain
Engine	3.2 L I6 S50B32 (1998–2000 non-US/CA) S52B32 (1998–2000 US/CA) S54B32 (2001–2002 world)
Transmission	5 speed manual
Dimensions
Wheelbase	2,459 mm (96.8 in)
Length	4,025 mm (158.5 in)
Width	1,740 mm (68.5 in)
Height	1,266 mm (49.8 in)
|uk|Kerb|Curb}} weight	1,399 kg (3,084.3 lb)
Chronology
Successor	Z4 M Roadster

The BMW M Roadster was designed to be the performance version of the BMW Z3, and there were significant differences between the two variants. The body of the Z3 M Roadster had a few differences compared to the standard Z3 models. These included front and rear bumpers, gills, boot and mirrors.

Under the skin many of the components were beefed up with the rear suspension being derived from the E30 M3 and the front suspension and brake system being taken from the E36 M3 Evo. Based on the E36 platform, the Z3 Roadster was considered the E36/7 platform. The M Roadster could run a wider track under the flared wheel arches as well as wider wheels and tires to try to tame the increased power. Standard tyre sizes for the M Roadster is 225/45r17 at the front and 245/40r17 at the back. The low offset of the rear wheels allows plenty of flexibility to increase the rear tire width. A dual exhaust system fed each set of three cylinders to two dual tailpipes. The Z3 M roadster was the first BMW to feature this quad exhaust design which has since become a BMW M division signature.

The interior had a different look to the standard Z3, including making the sport package M-version steering wheel standard on the M and including different instrumentation such as an oil temperature gauge. Finally, the car was available in M-specific colors which were not released for the regular Z3, at least in the early production years (not counting BMW's Individual program).

Early cars featured ABS as standard. ASC traction and stability control also became standard equipment on US-market cars in 1999 and in 2001 M roadsters worldwide were upgraded to BMW's DSC traction control system. The Z3 was facelifted, but in common with other BMW M vehicles, the M roadster's appearance was not updated.

Production Numbers

In the 5 years from 1998 to 2002, approximately 15,000 M Roadsters were produced for both European and North American markets. This is compared to the 300,000 standard Z3s produced in the same time frame. This makes them very rare and highly desired by car and performance enthusiasts.

Type	Spec	Engine	Dates	Production
CK91	European LHD	S50	09/1996 – 06/2000	3,557
CK92	European RHD	S50	11/1997 – 06/2000	918
CK93	North American LHD	S52	02/1998 – 06/2000	8,938
CL91	European LHD	S54	02/2001 – 05/2002	283
CL92	European RHD	S54	02/2001 – 04/2002	79
CL93	North American LHD	S54	02/2001 – 05/2002	1,600

1998-2000

1998-2000 models use the drivetrain of the E36 M3. Therefore, the European-spec model is fitted with the 321 PS (317 hp; 236 kW) S50B32 engine and the North American-spec model uses the 240 hp (179 kW) S52B32 engine.

The gearbox is a ZF Type C 5-speed manual, but the North American version is the only one fitted with BMW’s ASC+T traction control system (as of 9/98 production) until the facelift. The final drive is either 3.23:1 (S52) or 3.15:1 (S50 and S54). A limited slip differential with a maximum locking of 25 percent is standard.

The M roadster is electronically governed to 155 mph (249 km/h),

2001-2002

2001-2002 models use the engine from the E46 M3. Therefore, both European and North American models use the S54B32 engine. Slight differences in power exist between North American and European Z3M's and all Z3 M roadster S54 engines are down slightly on power compared to the E46 M3.

One way to determine differences in the engines outfitted in each year's production is to refer to the VIN. Because the US S52, European S50 and S54 engines have distinct visual differences, it is also easy to determine the specific engine by looking at it.

The other major addition to the revised M roadster is an M-tuned version of electronic stability control (called "DSC" by BMW). DSC intervention can be reduced or disabled via a console-mounted button.

All S54-powered M roadsters have an electronically limited top speed of 155 mph (249 km/h).

Chassis

Like all Z3s, the M roadster’s suspension is made up of MacPherson struts in the front and semi-trailing arms in the rear. However, compared to the six-cylinder Z3 roadster, the M roadster included modifications such as wider front and rear tracks (by 0.4 in (10.2 mm)), reduced ride height (by 1.1 in (27.9 mm)), modified front suspension geometry, firmer springs and shocks, thicker anti-roll bars, stronger semi-trailing arms and a reinforced subframe.

When the M roadster switched to the S54 engine (2/01 production), the chassis was upgraded to the even stiffer springs and shocks developed for the M coupe.

Brakes

The M roadster adopted the brakes from the contemporary E36 M3, four-wheel vented discs measuring 12.4 in (315.0 mm) in the front and 12.3 in (312.4 mm) in the rear. In addition, all M roadsters except those produced for the U.S. market were equipped with two-piece "floating" front discs.

The U.S. market was denied the more efficient two-piece discs offered in the rest of the world because BMW of North America was concerned that, if not properly maintained, the discs presented the possibility of failing, thus creating a legal liability. However, M roadsters produced for the Canadian market were equipped with the floating discs.

Wheels and tires

All M roadsters use the same size tires (225/45ZR17 in the front and 245/40ZR17 in the rear) mounted on one of two versions of the five-spoke "M RoadStar" alloy wheel. Both are sized 7.5x17-inch (front) and 9x17-inch (rear), but there are two distinct finishes: Early M roadsters (S50 and S52 engines) feature a Hyper Silver finish, while the later models (S54 engine) utilize a darker Shadow Chrome finish.

Exterior design

The M roadster is based on the wider six-cylinder Z3 roadster body, but adds a more aggressive front fascia with brake cooling ducts in place of foglights, unique side gill vents with the M logo, oval shaped M side-view mirror, a lower rear bumper with four exposed exhaust tips and a relocated rear license plate (located between the taillights instead of within the bumper). NOTE: The M roadster was never updated to the reshaped rear fenders and taillights introduced on all other Z3 roadsters as part of the April, 1999 revision.

The exterior of the S54-powered M roadster shares all of its body panels with that of the earlier version. Only the curved M badges and Roadstar alloy wheels with Chrome Shadow finish are unique to the newer model. It is also available in several exterior colors shared with the E46 M3: Laguna Seca Blue (448), Steel Gray metallic (400) and Phoenix Yellow metallic (445).

The North American-spec version of the M roadster is visually very similar to the European version, but can be identified by its amber side marker lights (and turn signal lenses on cars built before September, 1998) in the front bumper, "free form" headlights in place of the ellipsoid units and twin side-mounted rear license plate illumination lights instead of the single bumper-mounted design. Later year US spec cars came standard with clear headlights and are visually indistinguishable from their European counterparts.

Interior design

The interior of the M roadster features several unique items including a chrome-ringed instrument cluster with red needles and the M logo, three auxiliary chrome-ringed gauges in the center console, power and heated sport seats with special pleated leather trim (monotone black or two-tone), a 375 mm three-spoke M steering wheel with tri-color stitching, an illuminated M leather shift knob with the M logo on the shift pattern and a chrome boot surround, an oval-shaped rear-view mirror, leather door pulls and center console trim, chrome inside door handles, and door sill plates with the "M" logo.

The most significant alteration to the interior of the revised M roadster is the addition of grey-faced gauges. In some markets, there is also a smaller auto-dimming rear-view mirror with chrome surround. Finally, two interior color combinations (Evergreen/Black and Kyalami Orange/Black) are discontinued on the newer model, while Laguna Seca Blue/Black and Dark Beige interiors are available.

The interior of all M roadsters are essentially identical except for the instruments. In the main cluster, early Euro-spec cars have a 280 km/h / 170 mph speedometer and a tachometer that reflects the S50 engine's 7,200-rpm redline, while North American models have a 160 mph / 260 km/h speedometer and a tachometer with a redline graduated between 6,500 and 7,000 rpm to reflect the S52 engine's variable redline. In the center console, European models have an outside temperature gauge instead of the voltmeter used in North American editions.

The later S54-powered M roadsters all have essentially the same grey-faced instruments, including a 280 km/h / 170 mph speedometer and an outside temperature gauge (Fahrenheit on U.S. models, Celsius for all others) instead of the voltmeter..

Equipment

Compared to other M models, there are only slight variations in standard and optional equipment for the M roadster, depending on the market and production date. Because all M roadsters have Nappa leather upholstery, air conditioning, power seats with two-stage heating and (from 9/98) a power-folding soft top, the list of options is short. In general, it included cruise control (standard in some markets), headlight washers (not offered in the U.S.), a removable body-color hardtop and various audio systems.

Z4 M Roadster (2006–2008)

BMW E85 M Roadster
Overview
Manufacturer	BMW
Also called	Z4 M Roadster, MZ4
Production	2006–2008
Designer	Anders Warming
Body and chassis
Class	Roadster Sports car
Body style	2-door convertible
Layout	FR layout
Platform	E85
Related	BMW Z4
Powertrain
Engine	3.2 L (3,246 cc) S54B32 I6
Chronology
Predecessor	Z3 E36/7 M Roadster

The BMW M Roadster has been the BMW Z4 M Roadster launched in late 2006. Called the M Roadster, it's powered by the same 3.2 L (3,246 cc), 8,000 rpm, S54 inline-six engine as the E46 M3, North American Z4 M models produce 246 kW (334 PS; 330 hp), 3 hp less than the North American M3. In other markets, the power output is the same 252 kW (343 PS; 338 hp) at 7900 rpm and 365 N⋅m (269 lbf⋅ft) of torque at 4900 rpm as the M3, a new 6-speed "Type H" manual transmission is used. Engine management system however is specific to the Z4M: the Siemens MSS70 with higher processing power (64 million calculations per second) than the MSS54 (25 million CPS) in the M3. Other performance parts borrowed from the M3 include the CSL's compound (aluminum hubs, stainless steel pins, cross drilled iron floating rotors) brakes and most of the M3's suspension components. Other changes include a hydraulic steering setup which provides better feel than the electric system in standard Z4 models. Weighing 1,450 kg (3,200 lb), the M Roadster has been tested by major U.S. car magazines to accelerate from 0-60 mph (97 km/h) in 4.7 seconds, which is slightly quicker than the Porsche Boxster S and Porsche Cayman S. Top speed is electronically limited to 155 mph (249 km/h).

A new 6-speed manual transmission is used since the M3's original 6-speed doesn't fit the Z4's chassis. which is the only transmission available in the M Coupe/Roadster; its final gear ratios are virtually the same as those of the M3.

The M Roadster's MSRP is $52,100. A fixed-roof version (the M Coupe) is also available, though marginally heavier. Around the Top Gear test track, the BMW set a (wet track) time of 1:26.0 which is 0.8 of a second faster than the Base Corvette C6 LS2.

Options included a premium package (cruise control, power memory seats, upgraded audio, BMW Assist system), heated seats, extended leather, navigation and a body colour aluminium hardtop.

Production Figures
Coupes: Worldwide: 4,275; North America: 1,815.
Roadsters: Worldwide: 5,070; North America: 3,042

Awards

• The Z3 M Roadster was in Car and Driver's "Ten Best" (1999)
• "Design of the Year" award for the M Coupe in Automobile Magazine (1999)

External links

• BMW M "M Classics" Z3 M Roadster
• BMW Z3 Club
• BMW Z4M Production CSV File – With Build Options and Dates for all North American Z4Ms
• Archived BMW Z4 M Roadster/Coupe Owners Manuals E85/E86 Part No. 01 41 0 012 980

zh:BMW M Roadster