Powertrain families
N46 petrol I4 · M54/N52 petrol I6 · S54 M engine
Z4 (E85/E86) — Roadster
2002–2008
Editorially reviewedReviewed 2026-08-10; market and model-year scope is stated in the record sources.
- Internal code
- E85
- Production
- 2002–2008
- Body style
- 2-door roadster
- Platform
- longitudinal layout · rear-wheel drive
Body variants
Z4 → E85/E86 → Roadster
Z4 E85/E86: history, design and engineering
How this generation came about, what made it different and how the selected roadster fits into the family.
The first Z4 launched as the E85 roadster in 2002, replacing Z3 with a stiffer, larger two-seat body and electric power steering. Spartanburg produced the roadster, whose soft-top packaging and dimensions remain distinct from the fixed-roof E86.
A 2006 revision brought updated styling and engines and coincided with the E86 coupé, offered with six-cylinder power. Z4 M Roadster and Coupé used the S54 engine and hydraulic steering and are separately engineered M derivatives rather than ordinary 3.0si equipment packages.
Four- and six-cylinder regular engines varied by region, and North American and European badges did not always map to identical outputs. Roadster, coupé and M rows therefore require their own body, transmission and market fields.
2002–2008generation lifecycle
2body branches
3engine/drive families
6range designations
E85/E86factory code
longitudinal layout · rear-wheel drivearchitecture
Roadster: dimensions and packaging
Dimensions can change with body, market and model year, so this page keeps them tied to the exact factory branch.
Length4,091 mm
Width1,781 mm
Height1,299 mm
Wheelbase2,495 mm
Luggage240–260 L
Fuel tank55 L
Seats2
Doors2-door roadster
Engines and powertrains
The generation could span very different engines and drivetrains. The table keeps output, gearbox, market and production period together.
Factory modification matrix
Documented roadster applications; output and availability remain market- and model-year-specific.
| Model | Years | Engine | Output | Transmission | Drive | Market | Source |
|---|---|---|---|---|---|---|---|
| Z4 2.0i | 2005–2008 | N46B20 2.0 L inline-four | 150 PS | 6MT | RWD | Europe | BMW Z4 Roadster and Coupé technical data (10/2006) |
| Z4 2.2i | 2003–2005 | M54B22 2.2 L inline-six | 170 PS | 5MT / 5AT | RWD | Europe | BMW Z4 (E85/E86) |
| Z4 2.5i | 2003–2008 | M54B25 / N52B25 inline-six | 177–192 PS | 5MT / 6MT / 5AT / 6AT | RWD | Global range | BMW Z4 Roadster and Coupé technical data (10/2006) |
| Z4 2.5si | 2006–2008 | N52B25 2.5 L inline-six | 218 PS | 6MT / 6AT | RWD | Europe | BMW Z4 Roadster and Coupé technical data (10/2006) |
| Z4 3.0i | 2002–2005 | M54B30 3.0 L inline-six | 231 PS | 6MT / 5AT | RWD | Global range | BMW Z4 (E85/E86) |
| Z4 3.0si | 2006–2008 | N52B30 3.0 L inline-six | 265 PS | 6MT / 6AT | RWD | Global range | BMW Z4 Roadster and Coupé technical data (10/2006) |
| Z4 M Roadster / M Coupé | 2006–2008 | S54B32 3.2 L inline-six | 343 PS | 6MT | RWD | Global range | BMW Z4 M Roadster (E85) |
Factory designations
2.0i · 2.2i · 2.5i/si · 3.0i/si · M Roadster · M Coupe
Petrol engines
Inline and V engines are grouped by engine family, displacement, induction system and emissions specification.
Diesel derivatives
Where diesels were offered, output, injection generation and emissions hardware are recorded market by market.
How power reaches the road
Gearboxes, driven wheels and final-drive hardware changed with engine, market and production date.
Transmissions
Gearbox type and unit code follow engine, market and production date. Gear count alone does not identify the transmission.
Driven wheels
Catalog architecture: longitudinal layout · rear-wheel drive. All-wheel-drive availability and hardware remain derivative-specific.
Final drive
Ratio, differential type and electronic control belong to the exact derivative and can differ on performance models.
What changed underneath
Suspension, brakes, safety systems and electronics evolved across the range, even when cars shared the same basic architecture.
Body-branch dimensions
- E85: 4,091 mm × 1,781 mm × 1,299 mm
- E86: 4,091 mm × 1,781 mm × 1,268 mm
Body & suspension
- Mounting points and geometry follow the body branch
- Springs and dampers follow axle load and chassis package
- Wheels and permitted loads follow the factory label
Brakes & steering
- Brake size follows engine and equipment
- Assistance type and steering ratio can change
- ABS/DSC generation follows model year
Passive safety
- Airbag count varies by market and year
- SRS parts are VIN-specific
- Structural repairs require factory procedures
Electronics
- Vehicle-bus generations changed during production
- Control-unit software levels must remain compatible
- Retrofits are recorded separately from factory equipment
How the generation evolved
The important launches, additions and updates did not always happen at the same time for every body or market.
E85 roadster launch
The first Z4 entered production at Spartanburg as Z3's open-top successor.
Regional range growth
Four- and six-cylinder derivatives broadened the roadster offer.
Update, coupé and Z4 M
The E86 fixed roof and separately engineered M models joined the revised range.
US production ends
E85/E86 production ended before the German-built E89 generation.
The versions that stood apart
Performance models, option packages and regional editions may look related, but their engineering and production identity can be very different.
Roadster
E85Z4 E85 is a distinct E85/E86 body branch. A purpose-designed two-seat open sports car with compact packaging and a driver-focused cockpit. Engines/drive: N46 petrol I4, M54/N52 petrol I6, S54 M engine.
Coupe
E86Z4 E86 is a distinct E85/E86 body branch. A lower-roof two-door body with longer doors and a more overtly sporting brief than the corresponding sedan. Engines/drive: N46 petrol I4, M54/N52 petrol I6, S54 M engine.
Inside the car
Cabin technology and standard equipment changed by country and year; a build sheet remains the best guide to one individual car.
Cabin & comfort
- Trim and seats follow option codes
- Climate systems vary by market
- Audio and navigation changed by model year
Lighting & assistance
- Lamp technology and modules follow production date
- Driver assistance cannot be inferred from buttons alone
- Regional rules affect lighting and warnings
What to check today
A practical starting point for inspecting and maintaining a car from this generation — not a diagnosis of an individual example.
Identify first
- Match VIN on body and documents
- Obtain the factory option list
- Confirm market and production date
Inspect the structure
- Check repairs and corrosion
- Assess suspension, brakes and tyres
- Compare fitted parts with factory specification
Mechanical history
- Read faults with compatible diagnostics
- Verify engine and transmission maintenance
- Separate invoices from unsupported verbal history
| Item | Interval / trigger | Catalog note |
|---|---|---|
| Engine oil & filter | CBS/factory schedule; time and mileage for historic cars | Oil approval follows the exact engine and market. |
| Brake fluid | Time-based factory schedule | ABS/DSC-compatible bleeding procedure is required after hydraulic work. |
| Coolant | Factory schedule and condition | Fluid specification and bleeding method are generation-specific. |
| Transmission & final drives | Unit type and operating conditions | Use the exact approved fluid; no one interval fits every derivative. |
How to identify the exact car
The badge and registration year tell only part of the story; production date, body code, engine and factory options complete it.
- Factory body codes
- E85 — Roadster; E86 — Coupe
- Range designations
- 2.0i, 2.2i, 2.5i/si, 3.0i/si, M Roadster, M Coupe
- Powertrain families
- N46 petrol I4, M54/N52 petrol I6, S54 M engine
- VIN
- Identifies model, plant and production branch and keys the parts catalog and factory equipment record.
- Production date
- More useful than first-registration year when choosing parts and locating technical revisions.
- Type code
- Refines engine, body, market and transmission combination.
- Option codes
- Confirm factory equipment; later retrofits are recorded separately.
- Unit number
- Supports engine or gearbox originality checks and component applicability.
Where the information comes from
The story is mapped through English Wikipedia and its bibliography, then important dates and technical claims are checked against BMW material.
- 01BMW Z4 (E85)Wikipedia contributors
Secondary roadster, coupé, M and facelift overview.
- 02The BMW Z4 Final EditionBMW Group PressClub
Factory retrospective covering the first Z4 generation, Spartanburg production and Z4 M engineering.
Notes and limitations
- Research revision dated 2026-08-10: English Wikipedia was used as a subject and bibliography map; key claims were checked against the listed primary BMW Group material.
- E85 and E86 are separate body branches; coupé data begins only with the 2006 fixed-roof program.
- Z4 M steering, engine and chassis fields must not inherit regular 3.0si values.
- Tree years describe the worldwide generation lifecycle; individual market dates may be narrower.
- Exact dimensions, power, weight and emissions belong at body, engine, market and model-year level.
- Known-issue guidance is editorial context and never replaces inspection of the individual vehicle.
2 primary references · market differences documentedPhotography: Tokumeigakarinoaoshima, CC0 · Wikimedia Commons. Rights checked 2026-08-06; wikimedia commons 1,800 px derivative downloaded; local 640 px and 1,280 px avif versions created without cropping.Updated 6 August 2026