Otto Explains — Engines & Drivetrains
Iconic BMW Engines & Drivetrains
Short Answer
BMW’s best-known engineering includes a four-cylinder that grew into a Formula One champion, high-revving M engines, the V12, VALVETRONIC, turbocharged petrol and diesel engines, xDrive all-wheel drive, the SMG gearbox and, now, 800-volt electric drive. Each introduced something new, and Otto explains what that was, with the car it first appeared in.
Which BMW engine family won a Formula One world title?
The four-cylinder BMW developed for the 1500, shown in 1961, had an overhead camshaft and V-arranged valves. Enlarged to 1,499 cc as the M115, it became the forefather of every BMW four-cylinder engine built up to 1990, and BMW’s later six-cylinders kept its 100 mm cylinder spacing. Its best-known descendant went racing: in 1982 BMW entered Formula One as an engine supplier with a 1.5-litre turbocharged four-cylinder built on a production engine block. It won its first race in Canada in June 1982, and in 1983 Nelson Piquet became world champion in a Brabham BMW.
When did BMW start turbocharging its engines?
The 2002 turbo, shown in September 1973, had the first exhaust turbocharger in a European production car and made 170 bhp from 1,990 cc, but it arrived during the oil crisis and stayed a marginal model. The first 7 Series followed in 1980 with the 745i and its turbocharged six-cylinder of 252 hp. A later landmark was the 335i of 2006: its 3.0-litre six had two turbochargers, each feeding three cylinders, and High Precision direct injection through centrally placed piezo injectors, giving 306 hp and 400 Nm from 1,300 to 5,000 rpm. How a turbocharger works is explained in turbocharger vs supercharger.
What made BMW M engines different?
Several BMW M engines became famous in their own right. The M1’s M88, a 3.5-litre six-cylinder with four valves per cylinder, produced 277 bhp, and modified as the M88/3 it moved into the M635 CSi and the first M5. The first M3 used a four-valve 2.3-litre four-cylinder, the S14B23, of up to 215 hp. The S54B32 six-cylinder of the M3 (E46) reached 343 hp, or 106 hp per litre, and BMW Group Classic notes it won ‘Engine of the Year’ several years running. The M5 (E39) brought the first V8 to an M model: the 4,941 cc S62B50, with electronically controlled individual throttles and double VANOS, made 400 hp and drove through a six-speed manual gearbox.
What was special about BMW’s V12?
In February 1987 BMW released the details of the 750i’s twelve-cylinder engine: 300 hp from five litres, in what BMW calls the first German 12-cylinder luxury model in half a century. The V12 grew to 5.4 litres and 326 hp in the third-generation 7 Series, to 6.0 litres and 445 hp in the 760i of 2003, and gained twin turbochargers and 544 hp in 2008; the M760Li xDrive of the sixth generation had 610 hp. The difference between V and inline layouts is covered in engine designs explained.
What is BMW VALVETRONIC?
Most petrol engines control their power with a throttle butterfly that restricts the air coming in. VALVETRONIC does it differently: the engine varies how far the intake valves open, infinitely, to set how much mixture enters the cylinders, which BMW calls throttle-free load control. It first appeared in 2001 in the 316ti Compact, the first car in the world with a VALVETRONIC engine, and BMW put the fuel saving at around ten per cent. The same year the 735i and 745i of the fourth-generation 7 Series received new eight-cylinder engines with VALVETRONIC.
How did BMW’s diesel engines develop?
The second-generation 5 Series of 1981/82 brought the 524td, a 2.4-litre turbodiesel of 115 hp. In the 3 Series, the 324d (E30) was BMW’s first diesel in its compact saloon, and the 324td of 1987 added a turbocharger and Digital Diesel Electronics. The 320d of the fourth-generation 3 Series (1998) had BMW’s first diesel engine with direct injection, and the 740d of 1999 was, as BMW describes it, the world’s first saloon with a common-rail V8 diesel.
How did BMW all-wheel drive become xDrive?
BMW’s first all-wheel-drive car was the 325i ‘Allrad’, later called the 325iX, shown at the 1985 Frankfurt Motor Show. Its permanent system split the drive 37:63 between front and rear axles, using visco locks. The 525iX of 1991 brought an electronically controlled split. xDrive, which debuted in the X3 and X5 in 2003, uses an electronically controlled multi-plate clutch in the transfer case to vary the split continuously with the driving situation. Today xDrive in a BMW name means all-wheel drive, and sDrive means drive on one axle.
What gearboxes is BMW known for?
BMW M calls itself the world’s first supplier of an all-automatic manual gearbox: the Sequential M Gearbox (SMG), developed with Getrag and Sachs, went on sale in 1996 in the M3 only, and the second-generation SMG II with Drivelogic followed in the M3, with shifts as quick as 80 milliseconds. How an SMG works is explained in what an SMG transmission is. For comfort-oriented cars, BMW describes the fourth-generation 7 Series of 2001 as having the world’s first six-speed automatic fitted as standard.
How is BMW engineering changing with electric drive?
The i3 of 2013 used a 125 kW (170 hp) electric motor, and the i8 plug-in hybrid paired a 1.5-litre three-cylinder driving the rear wheels with a 96 kW (131 hp) electric motor driving the front wheels. The Neue Klasse iX3 of 2025 uses BMW’s sixth-generation eDrive technology, with 800V technology and cylindrical battery cells. For the iX3 50 xDrive, BMW gives provisional WLTP figures of up to 805 kilometres of range and charging at up to 400 kW, with 10 to 80 per cent charged in 21 minutes; range and charging times in everyday use depend on the car, the conditions and the charger.
What does this engineering mean for owners?
Many of these systems, from variable valve control and direct injection to turbochargers, xDrive and automated gearboxes, are electronically controlled, so their health depends on correct servicing as well as on mechanical condition. Follow BMW’s approved service schedule and oil specification for your car, taking your vehicle and operating conditions into account. A warning light, a change in how the car pulls or shifts, or a new noise needs diagnosis before parts are replaced: AutoTronix Lab diagnoses electronic and software faults, AutoTronix Garage repairs engines, gearboxes and drivetrains, and AutoTronix PERFORMANCE looks after performance models such as BMW M cars.
Common Questions
- Did BMW win in Formula One with a production engine block? Yes. BMW’s 1.5-litre turbocharged four-cylinder of 1982 was built on a production engine block, and in 1983 it powered Nelson Piquet’s Brabham BMW to the world championship.
- Which BMW was the first European production car with a turbocharger? The 2002 turbo, shown at the Frankfurt Motor Show in September 1973. Its exhaust turbocharger was the first in a European production car.
- Does a VALVETRONIC engine work without a throttle? BMW describes VALVETRONIC as throttle-free load control: the amount of mixture entering the cylinders is set by infinitely variable intake-valve lift rather than by a throttle butterfly.
- When did BMW first build a V12? BMW released the 750i’s V12 in February 1987: five litres and 300 hp, described by BMW as the first German 12-cylinder luxury model in half a century.