The BMW Z4 M40i (G29 LCI), introduced in September 2022 as part of the G29 Z4’s facelift, represents the performance pinnacle of the third-generation Z4 Roadster. Positioned as the flagship variant, it builds upon the foundation laid by the G29’s 2019 debut, offering a significant power upgrade and refined driving dynamics. Production continued through March 2026. The LCI (Life Cycle Impulse) brought styling updates, interior enhancements, and crucially, powertrain refinements to the Z4 range, with the M40i serving as the most potent expression of these changes. This model aimed to recapture the spirit of classic BMW roadsters, blending open-air driving enjoyment with modern performance technology.
Technical Specifications
| Brand | BMW |
| Model | Z4 |
| Generation | Z4 (G29 LCI, facelift 2022) |
| Type (Engine) | M40i (340 Hp) Steptronic |
| Start of production | September, 2022 |
| End of production | March, 2026 |
| Powertrain Architecture | Internal Combustion engine |
| Body type | Roadster |
| Seats | 2 |
| Doors | 2 |
| Combined fuel consumption (WLTP) | 7.9-8.1 l/100 km (29.8 – 29 US mpg, 35.8 – 34.9 UK mpg, 12.7 – 12.3 km/l) |
| CO2 emissions (WLTP) | 179-184 g/km |
| Fuel Type | Petrol (Gasoline) |
| Acceleration 0 – 100 km/h | 4.5 sec |
| Acceleration 0 – 62 mph | 4.5 sec |
| Acceleration 0 – 60 mph | 4.3 sec |
| Maximum speed | 250 km/h (155.34 mph), Electronically limited |
| Emission standard | Euro 6d |
| Weight-to-power ratio | 4.6 kg/Hp, 217.3 Hp/tonne |
| Weight-to-torque ratio | 3.1 kg/Nm, 319.5 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 | 1565 kg (3450.23 lbs.) |
| Max. weight | 1860 kg (4100.6 lbs.) |
| Max load | 295 kg (650.36 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.) |
| 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.) |
| 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 | 8 gears, automatic transmission Steptronic |
| Front suspension | Spring Strut |
| Rear suspension | Independent multi-link suspension |
| 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 |
| Tires size | Front wheel tires: 255/40 R18, Rear wheel tires: 275/40 R18 |
| Wheel rims size | Front wheel rims: 9J x 18, Rear wheel rims: 10J x 18 |
Powertrain & Engine Architecture
At the heart of the Z4 M40i lies the BMW B58 3.0-liter inline-six engine. This engine, a member of the modular B-series family, is renowned for its smooth power delivery and responsiveness. Utilizing direct injection and a twin-scroll turbocharger, the B58 produces 340 horsepower at 5,000-6,500 rpm and a substantial 500 Nm (368 lb-ft) of torque between 1,600 and 4,500 rpm. The engine incorporates BMW’s VALVETRONIC variable valve timing and Double-VANOS variable camshaft timing systems, optimizing efficiency and performance across the rev range. The engine is longitudinally mounted, driving the rear wheels. Paired with the B58 is the ZF 8HP80 eight-speed automatic transmission, marketed by BMW as “Steptronic.” This transmission is known for its quick, smooth shifts and adaptive learning capabilities. It features a torque converter for smooth low-speed operation and a wide gear ratio spread to maximize both acceleration and fuel efficiency.
Driving Characteristics
The Z4 M40i delivers a distinctly sporty driving experience. The combination of the potent B58 engine and the eight-speed automatic results in a 0-60 mph time of around 4.3 seconds. The Steptronic transmission provides both automatic and manual shift modes, allowing drivers to tailor the driving experience to their preferences. In automatic mode, the transmission intelligently selects gears based on driving conditions and throttle input. The rear-wheel-drive configuration contributes to a balanced chassis and engaging handling. Compared to the base Z4 sDrive30i, the M40i offers significantly more power and torque, resulting in noticeably quicker acceleration and improved passing performance. While the sDrive30i prioritizes fuel economy and comfort, the M40i is geared towards enthusiasts seeking a more dynamic driving experience. The M40i’s suspension is tuned for a firmer ride, providing greater control in corners but potentially sacrificing some ride comfort.
Equipment & Trim Levels
The Z4 M40i came standard with a comprehensive list of features, including leather upholstery, power-adjustable seats with memory function, a premium sound system, and BMW’s iDrive infotainment system with a 10.25-inch touchscreen display. Standard safety features included automatic emergency braking, lane departure warning, and adaptive cruise control. Optional extras included a head-up display, a digital instrument cluster, and various interior trim options. The M40i also benefited from unique exterior styling cues, such as a more aggressive front bumper, larger air intakes, and M-specific badging. Interior trim options allowed for personalization, with choices ranging from aluminum to carbon fiber accents.
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, optimized for handling and ride comfort. The M40i benefits from a slightly stiffer suspension setup compared to lower trims. Braking duties are handled by ventilated disc brakes on all four wheels, providing ample stopping power. The electronic stability control system (DSC) includes features such as traction control and corner brake control, enhancing safety and stability. The M40i typically came equipped with larger brake rotors and calipers than the base Z4 models.
Market Reception & Comparison
The Z4 M40i was generally well-received by automotive critics, who praised its powerful engine, engaging handling, and refined interior. It was often compared favorably to its rivals, such as the Porsche 718 Boxster and the Audi TT RS. While the Z4 M40i offered a compelling combination of performance and luxury, some critics noted that its ride could be firm on rough roads. Fuel economy, while respectable for a performance roadster, was not a primary strength. Compared to the Z4 sDrive30i, the M40i commanded a significant price premium, reflecting its higher performance capabilities and more extensive feature set.
Legacy
The B58 engine has proven to be remarkably reliable, and the Z4 M40i’s powertrain is expected to offer long-term durability with proper maintenance. On the used car market, the Z4 M40i holds its value well, appealing to enthusiasts seeking a high-performance roadster. The G29 Z4, and particularly the M40i variant, represents a return to form for BMW’s roadster lineage, offering a compelling blend of modern technology and classic driving enjoyment. Its robust engine and well-engineered chassis ensure it will remain a desirable sports car for years to come.
