Technical Specifications
| Brand | BMW |
| Model | Z4 |
| Generation | Z4 (E89 LCI, facelift 2013) |
| Type (Engine) | 18i (156 Hp) sDrive Steptronic |
| Start of production | 2013 |
| End of production | 2016 |
| Powertrain Architecture | Internal Combustion engine |
| Body type | Roadster |
| Seats | 2 |
| Doors | 2 |
| Fuel consumption (urban) | 9.4 l/100 km (25 US mpg, 30.1 UK mpg, 10.6 km/l) |
| Fuel consumption (extra urban) | 5.3 l/100 km (44.4 US mpg, 53.3 UK mpg, 18.9 km/l) |
| Fuel consumption (combined) | 6.8 l/100 km (34.6 US mpg, 41.5 UK mpg, 14.7 km/l) |
| CO2 emissions | 159 g/km |
| Fuel Type | Petrol (Gasoline) |
| Acceleration 0 – 100 km/h | 8.1 sec |
| Acceleration 0 – 62 mph | 8.1 sec |
| Acceleration 0 – 60 mph | 7.7 sec |
| Maximum speed | 220 km/h (136.7 mph) |
| Emission standard | Euro 6 |
| Weight-to-power ratio | 9.1 kg/Hp, 109.9 Hp/tonne |
| Weight-to-torque ratio | 5.9 kg/Nm, 169 Nm/tonne |
| Power | 156 Hp @ 5000 rpm |
| Power per litre | 78.1 Hp/l |
| Torque | 240 Nm @ 1250-4400 rpm (177.01 lb.-ft. @ 1250-4400 rpm) |
| Engine layout | Front, Longitudinal |
| Engine Model/Code | N20B20A |
| Engine displacement | 1997 cm3 (121.86 cu. in.) |
| Number of cylinders | 4 |
| Engine configuration | Inline |
| Cylinder Bore | 84 mm (3.31 in.) |
| Piston Stroke | 90.1 mm (3.55 in.) |
| Compression ratio | 10:1 |
| Number of valves per cylinder | 4 |
| Fuel injection system | Direct injection |
| Engine aspiration | Twin-power turbo, Intercooler |
| Engine oil capacity | 5 l (5.28 US qt | 4.4 UK qt) |
| Coolant | 8.5 l (8.98 US qt | 7.48 UK qt) |
| Kerb Weight | 1420 kg (3130.56 lbs.) |
| Max. weight | 1750 kg (3858.09 lbs.) |
| Max load | 330 kg (727.53 lbs.) |
| Trunk (boot) space – minimum | 180 l (6.36 cu. ft.) |
| Trunk (boot) space – maximum | 310 l (10.95 cu. ft.) |
| Fuel tank capacity | 55 l (14.53 US gal | 12.1 UK gal) |
| Length | 4239 mm (166.89 in.) |
| Width | 1790 mm (70.47 in.) |
| Height | 1291 mm (50.83 in.) |
| Wheelbase | 2496 mm (98.27 in.) |
| Front track | 1511 mm (59.49 in.) |
| Rear (Back) track | 1562 mm (61.5 in.) |
| Ride height (ground clearance) | 130 mm (5.12 in.) |
| Drag coefficient (Cd) | 0.34 |
| Minimum turning circle (turning diameter) | 10.7 m (35.1 ft.) |
| Drivetrain Architecture | Rear wheel drive |
| Number of gears and type of gearbox | 8 gears, automatic transmission |
| Front suspension | Double wishbone |
| 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 | 225/45 R17 |
| Wheel rims size | 8J x 17 |
The BMW Z4 (E89) 18i sDrive Steptronic, launched in 2013 as part of the LCI refresh, offered a compelling entry point into the BMW roadster experience. Built on the E89 platform, which debuted in 2009, this variant was designed to broaden the Z4’s appeal by providing a more economical and accessible option. The LCI update brought subtle styling revisions, improved interior materials, and crucially, the introduction of the latest BMW EfficientDynamics technologies. The 18i, with its 156 horsepower engine and eight-speed automatic transmission, was aimed at drivers who valued comfort, fuel efficiency, and a relaxed driving experience.
Powertrain & Engine Architecture
At the heart of the Z4 18i lies the BMW N20B20A 2.0-liter inline-four cylinder engine. This engine is a key component of BMW’s modular engine family, known for its efficiency and responsiveness. The N20 utilizes direct fuel injection, a twin-scroll turbocharger, and variable valve timing (VANOS) and valve lift (Valvetronic) systems to optimize power delivery and fuel economy. The engine produces 156 horsepower at 5000 rpm and 240 Nm (177 lb-ft) of torque between 1250 and 4400 rpm. This torque curve provides good low-end grunt, making it suitable for everyday driving. The engine is longitudinally mounted, driving the rear wheels. The “Steptronic” transmission refers to BMW’s eight-speed automatic gearbox, known for its smooth shifts and efficiency. This transmission features a torque converter and allows for both fully automatic operation and manual gear selection via steering wheel-mounted paddles or the gear selector.
Driving Characteristics
The Z4 18i sDrive Steptronic delivers a comfortable and refined driving experience. While not as dynamically engaging as the higher-powered Z4 variants, it offers sufficient performance for enjoyable cruising and spirited driving on winding roads. The eight-speed automatic transmission is well-matched to the engine, providing smooth and timely gear changes. Acceleration from 0 to 60 mph takes approximately 7.7 seconds, and the car has a top speed of 136.7 mph. The relatively low power output means that the engine needs to be revved to extract the most performance, but the broad torque curve ensures that it remains responsive in most situations. Compared to the manual transmission versions, the Steptronic offers greater convenience, particularly in urban traffic. However, it does slightly diminish the driver’s sense of connection to the car.
Equipment & Trim Levels
The Z4 18i sDrive Steptronic came reasonably well-equipped as standard. Key features included leather upholstery, automatic climate control, a BMW Professional radio system with iDrive controller, and 17-inch alloy wheels. Optional extras included features like navigation, heated seats, park distance control, and a Harman Kardon sound system. The interior design was focused on providing a driver-centric experience, with a neatly laid-out dashboard and comfortable seats. The LCI update brought improvements to the interior materials, giving the cabin a more premium feel.
Chassis & Braking
The Z4 E89 utilizes a double wishbone front suspension and an independent multi-link rear suspension, providing a good balance between comfort and handling. The suspension is tuned to offer a relatively compliant ride, while still providing sufficient body control in corners. The Z4 18i is equipped with ventilated disc brakes on all four wheels, providing adequate stopping power. Anti-lock braking system (ABS) is standard, enhancing safety and stability. The steering is a rack-and-pinion system with electric power assistance, offering precise and responsive steering feel.
Market Reception & Comparison
The Z4 18i sDrive Steptronic was generally well-received by automotive critics as a sensible and enjoyable entry-level roadster. It was praised for its fuel efficiency, comfortable ride, and refined interior. However, some critics noted that the engine lacked the outright performance of the higher-powered Z4 variants. Compared to the Z4 20i, the 18i offered slightly better fuel economy but less power. The 20i, with its 184 horsepower, provided a more engaging driving experience. The Z4 18i also competed with other entry-level roadsters, such as the Audi TT and Porsche Boxster, offering a compelling alternative with its blend of comfort, style, and efficiency.
Legacy
The N20 engine, found in the Z4 18i, has proven to be a relatively reliable unit, although some owners have reported issues with the timing chain and cooling system. Regular maintenance, including oil changes and coolant flushes, is crucial to ensure long-term reliability. On the used car market, the Z4 18i sDrive Steptronic represents a relatively affordable way to experience BMW roadster ownership. Its combination of style, comfort, and fuel efficiency makes it a popular choice for drivers seeking a practical and enjoyable open-top car.
