Powertrain families
B48 petrol I4 · B58 petrol I6
Z4 (G29) — Roadster
2018–2026
Editorially reviewedReviewed 2026-08-10; market and model-year scope is stated in the record sources.
- Internal code
- G29
- Production
- 2018–2026
- Body style
- 2-door roadster
- Platform
- longitudinal layout · rear-wheel drive
Body variants
Z4 → G29 → Roadster
Z4 G29: history, design and engineering
How this generation came about, what made it different and how the selected roadster fits into the family.
G29 returned Z4 to an electrically operated fabric soft-top and was developed alongside the Toyota GR Supra while retaining a distinct BMW body, calibration and model range. Production took place at Magna Steyr in Graz rather than a BMW-owned assembly plant.
The range combined four-cylinder sDrive20i/sDrive30i derivatives and the six-cylinder M40i with strong regional variation. A six-speed manual became available for the M40i in 2024 as the Pure Impulse package; it is a transmission/equipment branch, not a separate body or full Z4 M.
BMW updated the model for 2023 and announced the Final Edition in November 2025. The direct factory release states that global production would end in March 2026, replacing the former open-ended lifecycle with a confirmed 2018–2026 boundary.
2018–2026generation lifecycle
1body branches
2engine/drive families
3range designations
G29factory 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.
Length4,324 mm
Width1,864 mm
Height1,304 mm
Wheelbase2,470 mm
Luggage281 L
Fuel tank52 L
Seats2
Doors2-door roadster
| Body | Code | Production | Doors / seats | Length | Luggage |
|---|---|---|---|---|---|
| Roadster | G29 | 2018–2026 | 2-door roadster / 2 | 4,324 mm | 281 L |
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 sDrive20i | 2018–2026 | B48B20 2.0 L turbo inline-four | 197 PS | 8AT | RWD | Europe | The new BMW Z4 (G29) |
| Z4 sDrive30i | 2018–2026 | B48B20 2.0 L turbo inline-four | 258 PS / 255 hp US | 8AT | RWD | Global range | The new BMW Z4 (G29) |
| Z4 M40i | 2018–2026 | B58B30 3.0 L turbo inline-six | 340 PS Europe / 382 hp US | 8AT | RWD | Global range | The new BMW Z4 (G29) |
| Z4 M40i Pure Impulse / Handschalter | 2024–2026 | B58B30 3.0 L turbo inline-six | 340 PS Europe / 382 hp US | 6MT | RWD | Global range | The BMW Z4 Pure Impulse Edition |
| Z4 Final Edition | 2026 | M40i specification · B58B30 | 382 hp US | 6MT / 8AT | RWD | North America | The BMW Z4 Final Edition |
Factory designations
sDrive20i · sDrive30i · M40i
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.
Electrification
Mild- and plug-in hybrids are separate derivatives; combustion-engine output must not be substituted for total system output.
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
- G29: 4,324 mm × 1,864 mm × 1,304 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.
Pebble Beach premiere
BMW revealed the third Z4 generation and its fabric-roof roadster body.
Graz production and rollout
Magna Steyr production supplied regional four- and six-cylinder ranges.
Update and manual M40i
Detail revisions preceded the six-speed Pure Impulse derivative.
Final Edition and production end
BMW announced the final edition and confirmed the March 2026 end of global production.
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
G29Z4 G29 is a distinct G29 body branch. A purpose-designed two-seat open sports car with compact packaging and a driver-focused cockpit. Engines/drive: B48 petrol I4, B58 petrol I6.
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
- G29 — Roadster
- Range designations
- sDrive20i, sDrive30i, M40i
- Powertrain families
- B48 petrol I4, B58 petrol I6
- 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 (G29)Wikipedia contributors
Secondary development, model, production and update overview.
- 02The BMW Z4 Final EditionBMW Group PressClub
Factory model history and direct confirmation of the March 2026 production end.
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.
- The generation boundary must be changed from present to 2026; dealer stock or registrations after March do not extend production.
- European 340 hp and North American 382 hp M40i figures are market-specific, not contradictory global outputs.
- 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, CC BY-SA 4.0 · 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