Otto Explains — Engines & Drivetrains
Iconic MINI Engines & Drivetrains
Short Answer
MINI’s defining engineering idea is the classic Mini’s layout: a small four-cylinder A-series engine mounted crosswise, driving the front wheels, with the gearbox underneath it. Every MINI since has kept front-wheel drive and a transverse engine. The BMW-era cars moved from a supercharged 1.6-litre to turbocharged three- and four-cylinder engines, added ALL4 all-wheel drive, and are now increasingly electric.
What made the original Mini’s layout special?
BMC told Alec Issigonis to use the existing A-series engine, so he changed how it was installed. The 848 cc, 34 hp four-cylinder sat crosswise at the front and drove the front wheels, and the four-speed gearbox sat beneath it, between the wheels, sharing the engine’s oil. The drivetrain and suspension were mounted on subframes, the springs were rubber cones rather than steel coils, and, according to BMW Group, the drive shafts used constant-velocity (homokinetic) joints for the first time in a car, which kept drive forces out of the steering. The result left 80 per cent of the car’s footprint for people and luggage.
How did the A-series engine grow?
John Cooper’s Mini Cooper of 1961 enlarged it to 997 cc and 55 hp, and the Cooper S of 1963 to 1,071 cc and 70 hp, kept below the 1,100 cc limit of its racing class; from 1964 the Cooper S used a 1,275 cc version. From 1967 standard Minis could have a 998 cc, 38 hp engine, and the 1275 GT of 1969 had a 59 hp 1.3-litre. The classic Mini gained fuel injection and a catalytic converter in 1991, and after 1992 every model used the 1.3-litre injection engine because of emission rules.
What other drivetrain ideas did the classic Mini try?
In 1964 BMC fitted Hydrolastic suspension, in which fluid-filled units at the front and rear of each side were connected so that a bump at one wheel also lifted the other end of the car; it was dropped after seven years, in 1971. From 1965 the Mini was also offered with an automatic gearbox that had four forward gears yet took up hardly more room than the manual, unusual for a small car at the time.
Which engines powered the first BMW-era MINI?
The 2001 MINI used a 1.6-litre 16-valve four-cylinder, which BMW said before launch would come from Tritec Motors, a BMW and DaimlerChrysler joint venture in Brazil. It gave 90 hp in the MINI One and 115 hp in the MINI Cooper, with a five-speed manual or a CVT continuously variable automatic with a six-step Steptronic mode; how a CVT works is explained in Otto’s CVT guide. The Cooper S of 2002 used a supercharger (compressor) to reach 163 hp, with a six-speed manual, and the MINI One D of 2003, the first diesel MINI, had a 1.4-litre turbocharged common-rail engine. The difference between supercharging and turbocharging is covered in Otto’s turbocharger and supercharger guide.
Where did the second-generation MINI’s engines come from?
In 2002 the BMW Group and PSA Peugeot Citroën agreed to develop a new family of small petrol engines for MINI, Peugeot and Citroën, designed by BMW Group research and development. In the MINI they arrived with the second generation of 2006, assembled at Hams Hall in England, and MINI’s own timeline calls them the Prince engine. The 1.6-litre MINI Cooper (120 hp) used fully variable valve control based on BMW’s VALVETRONIC instead of a throttle butterfly, while the Cooper S switched from a supercharger to a twin-scroll turbocharger with direct injection (175 hp). Both had a six-speed manual as standard, with an optional six-speed automatic.
What changed with the 2014 MINI engines?
The third-generation MINI introduced MINI TwinPower Turbo engines: a 1,499 cc three-cylinder in the MINI Cooper (136 hp), a 1,998 cc four-cylinder in the Cooper S (192 hp) and a three-cylinder diesel in the Cooper D. Depending on the engine, the six-speed manual could be replaced by a seven-speed Steptronic dual-clutch gearbox or an eight-speed Steptronic automatic.
How does MINI’s ALL4 all-wheel drive work?
ALL4 was developed for MINI and first fitted to the Countryman and the Paceman. It uses an electromagnetic centre differential to vary how drive is split between the front and rear axles. The MINI Cooper S E Countryman ALL4, MINI’s first plug-in hybrid, reached all four wheels differently: its three-cylinder petrol engine drove the front wheels and an electric motor the rear wheels.
What powers John Cooper Works models?
The first John Cooper Works models of 2008 used a 1.6-litre twin-scroll turbo engine with 211 hp, built at Hams Hall and based on the Cooper S engine as revised for the John Cooper Works CHALLENGE racing car. The 2019 John Cooper Works GP had a four-cylinder engine with more than 300 hp. The all-electric JCW Electric and JCW Aceman of 2024 have up to 258 hp and a boost function that adds 20 kW for a short time when the driver presses a paddle on the steering wheel.
How did MINI move to electric drive?
The MINI E, used in field trials in Britain from 2009, came first, and MINI says it laid the foundations for battery-electric production cars across the BMW Group. The MINI Cooper SE of 2020 was the first all-electric production MINI, with a 184 hp motor driving the front wheels. In the new MINI family the Cooper SE has 218 hp, and BMW Group gave preliminary WLTP ranges of up to 402 km for it, up to 462 km for the Countryman E and up to 433 km for the four-wheel-drive Countryman SE ALL4. Otto explains the difference between hybrid, plug-in hybrid and electric cars in a separate guide.
What should MINI owners keep in mind?
One badge has covered very different hardware. Over three generations the MINI Cooper S went from a supercharged 1.6-litre to a turbocharged 1.6-litre and then a turbocharged 2.0-litre, and the versions on sale vary from market to market. Before buying parts or judging a symptom, confirm which engine and gearbox your car actually has, keep to the service schedule the manufacturer sets for that exact car, and let a diagnosis, not the model’s reputation, point to the cause of a fault. At AutoTronix, Garage looks after mechanical work on engines, gearboxes and drivetrains, Lab handles electronic diagnostics, and PERFORMANCE covers performance vehicles.
Common Questions
- Did MINI use Peugeot engines? Not exactly. The second-generation MINI’s petrol engines came from a cooperation between the BMW Group and PSA Peugeot Citroën, but they were designed by BMW Group research and development and assembled at Hams Hall in England.
- Why did the classic Mini’s engine and gearbox share oil? Because Issigonis placed the gearbox beneath the engine to save space, the two shared one oil circuit, which left room under the bonnet for the radiator at the side.
- Does the MINI Cooper have a three-cylinder engine? Often, yes. The 2014 MINI Cooper used a 1.5-litre three-cylinder, and the petrol MINI Cooper C of the new family has a 156 hp three-cylinder, while the Cooper S uses a four-cylinder.
- What gearboxes have BMW-era MINIs used? Five- and six-speed manuals, a CVT automatic in the first generation, six-speed automatics, and, from the third generation, seven-speed dual-clutch and eight-speed Steptronic automatics depending on the engine.