The Mini Convertible Cooper D 1.5 (116 hp) Steptronic, introduced with the F57 facelift in 2018, represents a fuel-efficient and accessible entry point into the Mini Convertible range. Positioned as a diesel-powered option within the broader F57 generation (2015-2024), this variant aimed to provide a balance of open-top motoring enjoyment with improved economy. Production of this specific configuration was limited to the 2018 model year, coinciding with the mid-life refresh of the F57 series. It slots into the lineup below the more powerful Cooper and Cooper S models, targeting buyers prioritizing fuel efficiency and lower running costs over outright performance.
Technical Specifications
| Brand | Mini |
| Model | Convertible |
| Generation | Convertible (F57, facelift 2018) |
| Type (Engine) | Cooper D 1.5 (116 Hp) Steptronic |
| Start of production | 2018 |
| End of production | 2018 |
| Powertrain Architecture | Internal Combustion engine |
| Body type | Cabriolet |
| Seats | 4 |
| Doors | 2 |
| Fuel consumption (urban) | 4.3-4.5 l/100 km (54.7 – 52.3 US mpg, 65.7 – 62.8 UK mpg, 23.3 – 22.2 km/l) |
| Fuel consumption (extra urban) | 3.8-4.0 l/100 km (61.9 – 58.8 US mpg, 74.3 – 70.6 UK mpg, 26.3 – 25 km/l) |
| Fuel consumption (combined) | 4.0-4.1 l/100 km (58.8 – 57.4 US mpg, 70.6 – 68.9 UK mpg, 25 – 24.4 km/l) |
| CO2 emissions | 105-109 g/km |
| Fuel Type | Diesel |
| Acceleration 0 – 100 km/h | 9.9 sec |
| Acceleration 0 – 62 mph | 9.9 sec |
| Acceleration 0 – 60 mph | 9.4 sec |
| Maximum speed | 195 km/h (121.17 mph) |
| Emission standard | Euro 6 |
| Weight-to-power ratio | 11.1 kg/Hp, 90.3 Hp/tonne |
| Weight-to-torque ratio | 4.8 kg/Nm, 210.1 Nm/tonne |
| Power | 116 Hp @ 4000 rpm |
| Torque | 270 Nm @ 1750-2250 rpm (199.14 lb.-ft. @ 1750-2250 rpm) |
| Engine layout | Front, Transverse |
| Engine Model/Code | B37C15A |
| Engine displacement | 1496 cm3 (91.29 cu. in.) |
| Number of cylinders | 3 |
| Engine configuration | Inline |
| Cylinder Bore | 84 mm (3.31 in.) |
| Piston Stroke | 90 mm (3.54 in.) |
| Compression ratio | 16.5:1 |
| Number of valves per cylinder | 4 |
| Fuel injection system | Diesel Commonrail |
| Engine aspiration | Turbocharger, Intercooler |
| Engine oil capacity | 4.4 l (4.65 US qt | 3.87 UK qt) |
| Coolant | 6 l (6.34 US qt | 5.28 UK qt) |
| Kerb Weight | 1285 kg (2832.94 lbs.) |
| Max. weight | 1750 kg (3858.09 lbs.) |
| Max load | 465 kg (1025.15 lbs.) |
| Trunk (boot) space – minimum | 160 l (5.65 cu. ft.) |
| Trunk (boot) space – maximum | 215 l (7.59 cu. ft.) |
| Fuel tank capacity | 44 l (11.62 US gal | 9.68 UK gal) |
| Length | 3821 mm (150.43 in.) |
| Width | 1727 mm (67.99 in.) |
| Height | 1415 mm (55.71 in.) |
| Wheelbase | 2495 mm (98.23 in.) |
| Front track | 1501 mm (59.09 in.) |
| Rear (Back) track | 1501 mm (59.09 in.) |
| Ride height (ground clearance) | 115 mm (4.53 in.) |
| Drag coefficient (Cd) | 0.33 |
| Minimum turning circle | 10.8 m (35.43 ft.) |
| Drivetrain Architecture | Front wheel drive |
| Number of gears and type of gearbox | 7 gears, automatic transmission steptronic |
| Front suspension | Independent, type McPherson with coil spring and anti-roll bar |
| Rear suspension | Independent multi-link suspension |
| Front brakes | Ventilated discs |
| Rear brakes | Disc |
INTRODUCTION
The F57 Mini Convertible, launched in 2015 and facelifted in 2018, brought a modern take on the classic Mini Convertible formula. The Cooper D 1.5 Steptronic, introduced with the facelift, offered a diesel engine option paired with a seven-speed dual-clutch transmission (branded as ‘Steptronic’). This combination aimed to appeal to drivers seeking a more economical and relaxed driving experience compared to the petrol-powered Cooper or the performance-oriented Cooper S. The F57 generation represented a significant increase in size and refinement over its predecessor (R57), offering improved interior space and a more comfortable ride. The 2018 facelift brought subtle styling updates, revised interior trim, and updated technology.
Powertrain & Engine Architecture
The Cooper D 1.5 Steptronic utilizes the BMW Group’s B37C15A 1.5-liter three-cylinder diesel engine. This engine is part of the modular engine family, known for its compact size and efficiency. It features a turbocharger with an intercooler to boost power and torque. The engine employs a common-rail direct injection system, delivering fuel directly into the combustion chamber at high pressure for optimized combustion. The valvetrain utilizes four valves per cylinder, enhancing breathing and contributing to improved performance. The Steptronic transmission is a seven-speed dual-clutch transmission (DCT) offering quick and smooth gear changes. It provides both automatic and manual shift modes, allowing drivers to tailor the driving experience to their preferences. The engine produces 116 horsepower at 4000 rpm and 270 Nm (199 lb-ft) of torque between 1750 and 2250 rpm.
Driving Characteristics
The 1.5-liter diesel engine, while not offering the outright acceleration of the petrol variants, provides ample torque for everyday driving. The Steptronic transmission contributes to a smooth and refined driving experience, particularly in urban environments. Acceleration from 0-60 mph takes approximately 9.4 seconds, and the car has a top speed of 195 km/h (121 mph). The gear ratios are tuned for fuel efficiency, with taller gearing in higher gears to reduce engine speed at cruising speeds. Compared to the manual transmission versions of the Cooper D, the Steptronic offers greater convenience, but some drivers may find it less engaging. The diesel engine’s torque delivery makes it well-suited for relaxed cruising and overtaking maneuvers, although it lacks the responsiveness of the higher-output petrol engines.
Equipment & Trim Levels
The Cooper D 1.5 Steptronic typically came equipped with standard features such as air conditioning, power windows, central locking, and a basic audio system. The interior featured cloth upholstery and a Mini-specific dashboard design. Optional extras included leather upholstery, a premium sound system, navigation system, parking sensors, and a variety of styling packages. The F57 facelift also introduced updated infotainment systems with larger touchscreen displays and improved connectivity features. Trim levels could vary depending on the market, but generally, the Cooper D Steptronic sat in the mid-range of the Convertible lineup, offering a good balance of features and affordability.
Chassis & Braking
The F57 Mini Convertible utilizes a McPherson strut front suspension and a multi-link rear suspension, providing a comfortable and controlled ride. The suspension is tuned to balance handling and comfort, offering a sporty feel without being overly harsh. The Cooper D 1.5 Steptronic is equipped with ventilated front disc brakes and solid rear disc brakes. Anti-lock Braking System (ABS) is standard, enhancing braking performance and stability. The car’s weight distribution is relatively balanced, contributing to its agile handling characteristics. The steering is electric power-assisted, providing precise and responsive steering feel.
Market Reception & Comparison
The Mini Convertible Cooper D 1.5 Steptronic was generally well-received by critics for its fuel efficiency and comfortable driving experience. However, some reviewers noted that the diesel engine lacked the character and excitement of the petrol engines. Compared to the Cooper, the Cooper D offered significantly better fuel economy, making it a more practical choice for drivers covering long distances. Compared to the Cooper S, the Cooper D provided less performance but at a lower price point. Reliability reports suggest that the B37 engine is generally robust, but like all diesel engines, it requires regular maintenance and the use of high-quality diesel fuel.
Legacy
The Cooper D 1.5 Steptronic, while a relatively short-lived variant, represents a practical and efficient option within the F57 Mini Convertible range. On the used car market, these models are often sought after by buyers prioritizing fuel economy and lower running costs. The B37 engine has proven to be reasonably reliable, although potential buyers should ensure that the car has been properly maintained and that the diesel particulate filter (DPF) is functioning correctly. The combination of a fuel-efficient diesel engine and a smooth-shifting Steptronic transmission makes this variant a comfortable and enjoyable choice for open-top motoring.
