FOR 40 years BMW's M division has been the substance behind the company's claim of having created the Ultimate Driving Machine.
BMW's image was not always so well defined. The company scraped through the postwar era building a tadpole-shaped microcar called the Isetta along with some ponderous models and the occasional great beast like the 507 roadster.
But everything changed with the introduction of the Neue Klasse compact series of sedans in 1962. Starring the brilliant 2002 model, the Neue Klasse machines soon established BMW as the maker of an altogether new vehicle type: the sport sedan.
By the early 1970s, BMW's image was solidly linked to high performance, and the board of directors decided the company should control its motor sports destiny. On May 1, 1972, the tiny Sports department was replaced by BMW Motorsport -- the first in a wave of factory "tuner" divisions -- bursting with 35 employees under the supervision of Jochen Neerspach.
Mr. Neerspach, 33 at the time, had been a driver for the Porsche factory racing team and manager of Ford's European racing efforts. He immediately set his crew to building a version of the 2002, powered by a 16-valve 4-cylinder engine, for rallying.
For touring car racing, the 3.0 CSL was created. Based on the 3.0 CS luxury coupe, the CSL carried aluminum body panels and a 3.3-liter twin-cam version of BMW's in-line 6. The car won the European Touring Car Championship six times in 1973-79 and was the first car to wear the blue, violet and red stripes that, alongside a stylized M, became Motorsport's logo.
Emboldened by the 3.0 CSL's success, Motorsport took on the construction of a car built specifically for competition. What emerged was the midengine M1, a sleek supercar with a fiberglass body from Italy. Powered by a 3.5-liter version of the 6 used in the 3.0 CSL, it reached production in 1978, but by then its racing series had been canceled.
The roadgoing M1 models built to qualify the model for racing -- fewer than 500 were made -- were a critical success. When M1 production stopped in 1981, however, the car's 6-cylinder engine was orphaned, so the Motorsport division tucked a 282-horsepower version of it into the E24 6 Series coupe to create the M635CSi. That car was known as the M6 when it went on sale in the United States in 1987.
That first M6 defined the BMW roadgoing M car formula: a production BMW optimized for handling and braking, powered by a special high-revving engine backed by a manual transmission. The M5 followed the M6 in 1985, and the first M3 appeared in 1988 powered by a high-strung 192-horsepower 4-cylinder.
Though the M cars were aimed at enthusiasts, the cachet of the M brand logo grew quickly and soon was showing up not only on cars, but merchandise and accessories. Recognizing this, in 1993 BMW split the brand into two divisions. Motorsport would continue running BMW competition efforts while the new M division took charge of road cars and the M brand.
Though the M car formula held pure through the 1990s even as it was applied to almost every BMW vehicle line (the 7 Series sedans being the notable exception), the pull of the mass market was overwhelming. Four-cylinder M3 engines gave way to an in-line 6 and then a V-8. Automated manual transmissions began displacing pure manuals.
In 2010 the M badge finally found its way onto vehicles ill-suited to any sort of motor sport, the X5 M and X6 M crossovers powered by a twin-turbocharged V-8.
"It's become more of a marketing tool than the real specialized vehicles it used to be," said Rennie Bryant of Redline Performance, a BMW tuning shop in Pompano Beach, Fla. "The brand is pretty strong. But it's not a purist thing any more."
This article originally appeared in The New York Times.