The BMW Z4 (E89) 28i sDrive Steptronic, produced from 2011 to 2013, represents a significant iteration of BMW’s popular two-seater roadster. Positioned as a mid-range offering within the E89 Z4 lineup, it bridged the gap between the entry-level 23i and the performance-oriented 35i models. This variant aimed to deliver a balance of sporty handling, respectable performance, and everyday usability, appealing to drivers seeking an engaging open-top experience without the higher price tag or more aggressive tuning of its siblings. The E89 generation marked a departure from the previous Z4 (E85) with its retractable hardtop, offering improved security and weather protection.
Technical Specifications
| Brand | BMW |
| Model | Z4 |
| Generation | Z4 (E89) |
| Type (Engine) | 28i (245 Hp) sDrive Steptronic |
| Start of production | 2011 |
| End of production | 2013 |
| Powertrain Architecture | Internal Combustion engine |
| Body type | Roadster |
| Seats | 2 |
| Doors | 2 |
| Fuel consumption (urban) | 9.4 l/100 km (25 US mpg) |
| Fuel consumption (extra urban) | 5.3 l/100 km (44.4 US mpg) |
| Fuel consumption (combined) | 6.8 l/100 km (34.6 US mpg) |
| CO2 emissions | 159 g/km |
| Fuel Type | Petrol (Gasoline) |
| Acceleration 0 – 100 km/h | 5.5 sec |
| Acceleration 0 – 62 mph | 5.5 sec |
| Acceleration 0 – 60 mph | 5.2 sec |
| Maximum speed | 250 km/h (155.34 mph) |
| Weight-to-power ratio | 6.1 kg/Hp |
| Weight-to-torque ratio | 4.3 kg/Nm |
| Power | 245 Hp @ 5000-6500 rpm |
| Torque | 350 Nm @ 1250-4800 rpm (258.15 lb.-ft.) |
| 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.) |
| 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) |
| Kerb Weight | 1495 kg (3295.91 lbs.) |
| Max. weight | 1750 kg (3858.09 lbs.) |
| Max load | 255 kg (562.18 lbs.) |
| 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 track | 1559 mm (61.38 in.) |
| Drivetrain Architecture | Rear wheel drive |
| Number of gears | 8 |
| Gearbox type | Automatic transmission |
Powertrain & Engine Architecture
The heart of the Z4 28i is BMW’s N20B20A 2.0-liter turbocharged inline-four cylinder engine. This engine is a key component of BMW’s new generation of modular engines, known for its efficiency and performance. The N20 utilizes direct fuel injection, delivering fuel directly into the combustion chamber for improved combustion efficiency and reduced emissions. It also features BMW’s Valvetronic technology, which allows for stepless control of valve lift, optimizing engine breathing for both power and fuel economy. The single twin-scroll turbocharger provides a broad torque curve, minimizing turbo lag and delivering responsive acceleration. The engine is paired with BMW’s 8-speed Steptronic automatic transmission, known for its smooth shifts and quick response. This transmission offers both automatic and manual shift modes, allowing the driver to tailor the driving experience to their preferences.
Driving Characteristics
The Z4 28i sDrive Steptronic offers a compelling driving experience. While not as overtly sporty as the 35i, the 245 horsepower and 258 lb-ft of torque provide ample power for spirited driving. The 8-speed automatic transmission is well-tuned, offering smooth and quick shifts. The gear ratios are optimized for both acceleration and fuel efficiency. Compared to the 6-speed manual transmission available on other Z4 models, the automatic prioritizes ease of use and comfort. Acceleration from 0-60 mph takes approximately 5.2 seconds, making it a quick roadster. The rear-wheel drive configuration contributes to balanced handling, and the relatively lightweight construction (compared to some competitors) enhances agility. However, some reviewers noted that the automatic transmission can occasionally feel hesitant during downshifts, and the engine sound, while pleasant, lacks the character of a larger displacement engine.
Equipment & Trim Levels
The Z4 28i sDrive Steptronic came reasonably well-equipped as standard. Typical features included leatherette upholstery, automatic climate control, a power-retractable hardtop, BMW’s iDrive infotainment system with a 6.5-inch display, and 17-inch alloy wheels. Optional extras were plentiful, allowing buyers to customize their Z4. Popular options included premium leather upholstery, heated seats, a Harman Kardon premium sound system, navigation, park distance control, and adaptive headlights. The interior design was driver-focused, with a clean and modern layout. The dashboard featured a prominent center console with easy-to-reach controls.
Chassis & Braking
The Z4 E89 utilizes a MacPherson strut front suspension and a multi-link rear suspension. This setup provides a good balance of ride comfort and handling precision. The 28i model typically featured stabilizer bars to reduce body roll during cornering. Braking duties were handled by ventilated disc brakes at the front and either disc or drum brakes at the rear, depending on the specific configuration. The standard steering system is a rack-and-pinion setup with electric power assistance, providing precise and responsive steering feel. The chassis was designed to be relatively lightweight, contributing to the car’s agility.
Market Reception & Comparison
The Z4 28i sDrive Steptronic was generally well-received by automotive critics. It was praised for its balanced performance, comfortable ride, and well-equipped interior. Compared to the Z4 23i, the 28i offered a significant power boost, resulting in noticeably quicker acceleration. However, it was more expensive. Compared to the Z4 35i, the 28i was more fuel-efficient and offered a more accessible price point, but it lacked the 35i’s raw power and aggressive character. Fuel economy figures of around 34.6 US mpg combined were competitive for its class. Reliability was generally good, although some owners reported minor issues with the electronic systems.
Legacy
The BMW Z4 E89 28i sDrive Steptronic remains a desirable used roadster. The N20 engine has proven to be relatively reliable, although regular maintenance is crucial. The 8-speed automatic transmission is also generally dependable. The retractable hardtop is a significant selling point, offering year-round usability. Today, these Z4s can be found at reasonable prices, making them an attractive option for buyers seeking an affordable and engaging open-top driving experience. The E89 generation, and the 28i variant in particular, represents a sweet spot in the Z4 lineage, offering a blend of performance, comfort, and practicality that continues to appeal to enthusiasts.
