The BMW Z4 M40i (G29 LCI), introduced with the 2022 facelift and continuing through the 2026 model year, represents the performance pinnacle of the third-generation Z4 Roadster. Positioned as the flagship variant, it delivers a significant step up in power and driving dynamics compared to the base 2.0-liter models. The “LCI” designation signifies a Life Cycle Impulse, BMW’s term for a comprehensive mid-cycle refresh, bringing updated styling, technology, and refinements to the G29 platform. This variant is exclusively offered as a rear-wheel drive roadster, catering to enthusiasts seeking an engaging and sporty driving experience.
Technical Specifications
| Brand | BMW |
| Model | Z4 |
| Generation | Z4 (G29 LCI, facelift 2022) |
| Type (Engine) | M40i (340 Hp) |
| Start of production | 2024 year |
| End of production | March, 2026 year |
| Powertrain Architecture | Internal Combustion engine |
| Body type | Roadster |
| Seats | 2 |
| Doors | 2 |
| Combined fuel consumption (WLTP) | 8.7 l/100 km |
| Combined fuel consumption (US mpg) | 27 US mpg |
| Combined fuel consumption (UK mpg) | 32.5 UK mpg |
| Combined fuel consumption (km/l) | 11.5 km/l |
| CO2 emissions (WLTP) | 195-197 g/km |
| Fuel Type | Petrol (Gasoline) |
| Acceleration 0 – 100 km/h | 4.6 sec |
| Acceleration 0 – 62 mph | 4.6 sec |
| Acceleration 0 – 60 mph | 4.4 sec |
| Maximum speed | 250 km/h, Electronically limited (155.34 mph) |
| Emission standard | Euro 6e |
| Weight-to-power ratio | 4.6 kg/Hp, 219.4 Hp/tonne |
| Weight-to-torque ratio | 3.1 kg/Nm, 322.6 Nm/tonne |
| Power | 340 Hp @ 5000-6500 rpm |
| Power per litre | 113.4 Hp/l |
| Torque | 500 Nm @ 1600-4500 rpm (368.78 lb.-ft. @ 1600-4500 rpm) |
| Engine layout | Front, Longitudinal |
| Engine Model/Code | B58 |
| Engine displacement | 2998 cm3 (182.95 cu. in.) |
| Number of cylinders | 6 |
| Engine configuration | Inline |
| Cylinder Bore | 82 mm (3.23 in.) |
| Piston Stroke | 94.6 mm (3.72 in.) |
| Compression ratio | 11:1 |
| Number of valves per cylinder | 4 |
| Fuel injection system | Direct injection |
| Engine aspiration | Twin-power turbo, Intercooler |
| Valvetrain | VALVETRONIC, Double-VANOS |
| Engine oil capacity | 6.5 l (6.87 US qt | 5.72 UK qt) |
| Kerb Weight | 1550 kg (3417.17 lbs.) |
| Max. weight | 1860 kg (4100.6 lbs.) |
| Max load | 310 kg (683.43 lbs.) |
| Trunk (boot) space – minimum | 281 l (9.92 cu. ft.) |
| Fuel tank capacity | 52 l (13.74 US gal | 11.44 UK gal) |
| Length | 4324 mm (170.24 in.) |
| Width | 1864 mm (73.39 in.) |
| Width including mirrors | 2024 mm (79.69 in.) |
| Height | 1304 mm (51.34 in.) |
| Wheelbase | 2470 mm (97.24 in.) |
| Front track | 1594 mm (62.76 in.) |
| Rear (Back) track | 1589 mm (62.56 in.) |
| Front overhang | 907 mm (35.71 in.) |
| Rear overhang | 947 mm (37.28 in.) |
| Ride height (ground clearance) | 114 mm (4.49 in.) |
| Drag coefficient (Cd) | 0.31 |
| Minimum turning circle (turning diameter) | 11 m (36.09 ft.) |
| Drivetrain Architecture | Rear wheel drive |
| Number of gears and type of gearbox | 6 gears, manual transmission |
| Front suspension | Spring Strut, Transverse stabilizer |
| Rear suspension | Independent multi-link spring suspension with stabilizer |
| Front brakes | Ventilated discs |
| Rear brakes | Ventilated discs |
| Assisting systems | ABS (Anti-lock braking system) |
| Steering type | Steering rack and pinion |
| Power steering | Electric Steering |
| Front wheel tires | 255/35 R19 |
| Rear wheel tires | 285/30 R20 |
| Front wheel rims | 9J x 19 |
| Rear wheel rims | 10J x 20 |
INTRODUCTION
The Z4 M40i, launched alongside the LCI update, builds upon the foundation of the G29 Z4, a model that marked BMW’s return to the two-seat roadster segment after a hiatus. The G29, unveiled in 2018, was co-developed with Toyota, resulting in the simultaneous release of the Toyota Supra. The LCI update brought a sharper focus on performance and refinement, with the M40i serving as the range-topping model. It directly competes with other premium roadsters like the Porsche 718 Boxster and the Mercedes-Benz SLC (now discontinued).
Powertrain & Engine Architecture
At the heart of the Z4 M40i lies the B58 3.0-liter inline-six engine, a powerplant renowned for its smoothness, responsiveness, and ample power delivery. This engine utilizes direct fuel injection, a twin-scroll turbocharger, and BMW’s VALVETRONIC variable valve timing and lift system. VALVETRONIC allows for precise control of valve timing and lift, optimizing engine efficiency and performance across the rev range. The B58 engine produces 340 horsepower at 5,000-6,500 rpm and 368 lb-ft of torque between 1,600 and 4,500 rpm. The engine is longitudinally mounted, driving the rear wheels. While a six-speed manual transmission was initially offered, the eight-speed ZF 8HP automatic transmission became the more common choice, offering quicker shifts and improved fuel efficiency. The automatic transmission features paddle shifters for manual control.
Driving Characteristics
The Z4 M40i delivers a distinctly sporty driving experience. The combination of the potent B58 engine and the rear-wheel-drive chassis results in brisk acceleration – 0 to 60 mph in approximately 4.4 seconds. The engine’s broad torque curve provides strong pull throughout the rev range, making it easy to overtake and maintain speed. The eight-speed automatic transmission shifts quickly and smoothly, and the paddle shifters allow for precise gear selection. The suspension is tuned for a balance between comfort and handling, providing a firm but not overly harsh ride. The steering is precise and well-weighted, offering good feedback to the driver. Compared to the 2.0-liter Z4 variants, the M40i offers a significantly more engaging and rewarding driving experience, with noticeably stronger acceleration and more confident handling.
Equipment & Trim Levels
The Z4 M40i comes standard with a comprehensive list of features, including leather upholstery, power-adjustable seats with memory function, a premium sound system, and a suite of advanced driver-assistance systems. Optional extras include adaptive suspension, a head-up display, and various interior trim options. The LCI update brought revised interior trim options and updated infotainment system with a larger touchscreen display. The standard interior upholstery is leather, with available options for extended leather trim and contrasting stitching. The dashboard features a driver-focused layout with a digital instrument cluster and a central touchscreen display.
Chassis & Braking
The Z4 M40i utilizes a lightweight chassis construction, incorporating high-strength steel and aluminum components. The suspension features a spring-strut front axle and a multi-link rear axle, both with stabilizer bars to reduce body roll. The braking system consists of ventilated discs on all four wheels, providing ample stopping power. The M40i benefits from a slightly stiffer suspension setup compared to the base Z4 models, further enhancing handling performance. The electronic power steering system provides precise and responsive steering feel.
Market Reception & Comparison
The Z4 M40i has been well-received by automotive critics, who praise its powerful engine, engaging handling, and refined interior. It is often cited as one of the most enjoyable roadsters on the market. Compared to the 2.0-liter Z4 models, the M40i offers a significant performance upgrade, but at a higher price point. Fuel economy is slightly lower than the 2.0-liter variants, but the added performance is generally considered worth the trade-off. Reliability has been generally good, with the B58 engine proving to be a robust and dependable powerplant.
Legacy
The Z4 M40i (G29 LCI) represents a compelling offering in the premium roadster segment. The B58 engine is widely regarded as one of BMW’s best, and its combination with the Z4’s balanced chassis makes for a truly enjoyable driving experience. As the final iteration of the G29 Z4, the M40i is likely to become a sought-after model on the used car market, particularly among enthusiasts who appreciate its performance and driving dynamics. The B58 engine’s reputation for reliability suggests that these vehicles should provide years of enjoyable motoring with proper maintenance.
