25 Years of BMW 12-Cylinder Engines

25 Years of BMW 12-Cylinder Engines

BMW passed a pretty impressive milestone recently. Their 12-cylinder engine program passed into it’s 25th year. BMW’s second-generation 7 Series, unveiled in 1986, revived the 12-cylinder engine, previously discontinued within BMW’s model range, as a top of the range option. Since 1987, BMW have been producing a 750i, complete with V12 engine. The original second-generation model attracted 3,000 pre-orders even before its Geneva debut!

The original 750i was the first post-Second World War 12-cylinder engine from a German manufacturer to appear in production form. However, BMW had produced a V12 engine as far back as 1971. The M33 was essentially two six-cylinder units merged to create a V12 unit with 60-degree cylinder bank angle, a displacement of five liters, petrol injection and a maximum output of 300hp. Yet it weighed 315 kilograms and was deemed too heavy.

That engine went back to the drawing board and engineers started work on the M66. It too was a 60-degree V12, and two displacement versions emerged, a 3.6 liter and a 4.5 liter. The larger version, whose output was bench-tested at 275hp in 1977, was 40 kilograms lighter than the M33. Yet the economic climate and the energy market at the time necessitated the shelving of the project.

The original 750i featured a production-ready, five-liter V12 alloy engine weighing 240 kilograms with a maximum output of 300hp at 5,200rpm and maximum torque of 450 Newton metres at 4,100rpm. By the time the second generation 7-Series was discontinued, BMW had sold 50,000 750i’s. One in six 7-Series was a 750i.

The next generation also featured a 750i which debuted in 1994. The M70, the M73 had a displacement of 5.4 liters and a maximum output of 326hp. By the time the next generation model emerged in 2001, BMW had shifted 73,776 V12-powered BMW 7-Series units. For the next generation, BMW moved further upmarket introducing the new 760i/Li models with a six-liter V12 engine delivering a maximum output of 445hp. This was far more advanced than any other BMW V12 prior to it.

The culmination, for the time being, is the BMW 760i/760Li. It’s the latest and greatest of BMW’s V12 power plants and the engine of choice for the 25th year of production. Internally it is known as the N74 and features TwinPower Turbo technology, direct petrol injection and Double-Vanos continuously variable camshaft timing.

The N74 develops maximum power of 544hp at 5,250rpm from a displacement of 5,972cc. Peak torque of 750 Newton meters is maintained between 1,500 and 5,000rpm. It also features an eight-speed automatic transmission, a 0-100km/h acceleration time of just 4.6 seconds and a limited top speed of 250km/h.

The N74 concludes the handy history that BMW provided for the 12-cylinder BMW unit’s 25th anniversary. Of course, you can also enjoy the mammoth gallery we’ve included and don’t forget to take a look at the Special Edition 25th Anniversary BMW 760Li too!

Published: October 27, 2012 11:28 pm

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