BMW 3 Series (E21)

From BMW Tech
(Redirected from BMW E21)
Jump to navigation Jump to search
BMW 320 (1977 - 1982)
1,364,039 built[1]
PredecessorBMW 2002
SuccessorBMW E30
ClassEntry-level luxury car / Compact executive car
LayoutFR layout
Body style(s)2-door coupé
2-door convertible
Engine(s)I4, I6
1.6-2.3 L

BMW E21 is the platform designation for the first BMW 3 Series compact executive car, produced by the German automaker BMW from 1975 to 1983. This series was the immediate successor to the BMW 2002 and was superseded by the BMW E30 platform.

Development and early history

Under the direction of its 51% percent shareholder, Herbert Quandt, BMW decided upon a replacement for their aging 2002. Without it, there was the distinct possibility of BMW leaving its core mission of building driver oriented cars, and alienating an existing customer base long enamored with the company's 2002 model.

Paul Bracq, Director of Design at BMW from 1970–1974, is credited with setting the design direction of the E21 3 Series, while Wilhelm Hofmeister is credited with first drawing the small forward wedge at the base of the C-pillar, a strong design trait of the first 3 Series. In 1975 Claus Luthe replaced Bracq and became the owner of the project.

In July 1975, BMW’s Board of Management first presented this new model series in the Munich Olympic Stadium for public appraisal. The frontal view of the new car was dominated by the BMW trademark kidney grille standing out clearly from the radiator cover. The styling of the new car bore a resemblance to the BMW E12 5 Series.

The wedge shape of the two-door model was distinctive, extending all the way to the unusually high rear end. In response to criticism of the tail design, a black plastic trim panel between the tail lights was added. The car's styling was otherwise well received.

Measuring 4355 millimeters (171.5 inches) in length, 1610 millimeters (63.4 inches) in width, and 1380 millimeters (54.3 inches) in height, the E21 Series continued the tradition of the New Class. With the wheelbase measuring 2563 millimeters (100.9 in), there was little body overhang in the rear wheel drive design. The track measured 1364 millimeters (53.7 in) at the front, and 1377 millimeters (54.2 in) at the rear.

The suspension incorporated rack and pinion steering and McPherson strut suspension at the front, and semi-trailing arm type independent suspension at the rear. The power assisted brakes were discs on the front wheels, while the rear wheels had drum brakes.

Initially, a Getrag four-speed manual was the standard transmission fitment. Five-speed Getrag gearboxes were fitted as standard in the 323i and others in later years, but were available at the car's release as an option, with gear ratio sets favoring either performance or economy. Alternatively, purchasers could opt for the ZF 3 HP-22 three-speed automatic transmission.

The cockpit design of the E21 marked the introduction of a new design concept, with the center console angled towards the driver. This feature has become part of BMW’s interior design philosophy for many years. As a sign of passive safety, all edges and control elements within the interior were rounded off and padded.

At the E21's release, three models were available: with 316 (1.6 litre), 318 (1.8 litre) and 320 (2.0 litre) versions of the BMW M10 four cylinder engine. To draw clear visual distinction within the new model series, the 320 models came with dual headlights, while the 316 and 318 had single round headlights.

At the end of 1975, the 320i was introduced; the engine was fitted with Bosch K Jetronic fuel injection, delivering 125 bhp (93 kW) on premium grade gasoline.

At introduction in the German market, the entry-level 316 retailed at DM 13 600, the 318 sold for DM 14 420, and the two 2.0 L models went for DM 15 330 and DM 17 400 respectively.

Ongoing evolution

In the mid 1970s, BMW had invested DM 110 million in a new engine series, designated as the M20.

At the 1977 Frankfurt Motor Show, BMW unveiled its new variants of the E21, featuring the new six-cylinder M20 engines. The four cylinder 320 model was replaced with the 320/6, featuring a two litre version of the M20 engine. The 323i model was introduced, featuring 2.3 litres and 143 bhp (107 kW), empowering this car with a top speed of approximately 190 km/h (118 mph). The braking system was also upgraded, with the 323i featuring disc brakes on all wheels.

In the meantime however, a performance gap had developed between the 98 bhp (73 kW) 318 and the new 320/6 delivering 122 bhp (91 kW). For the 1979/80 model year, the four-cylinder models were upgraded: the 1.8 litre power unit was revised and entered the market as a 90 bhp (67 kW) carburetor engine in the 316, while addition of Bosch K Jetronic fuel injection to the 1.8 litre engine raised the 318i to 105 bhp (78 kW).

Since there was now also room for a new entry-level model, the 315 powered by a 75 bhp (56 kW) 1.6 litre M10 engine made its appearance in 1981.


A European study conducted by BMW in 1980 showed that with a share of 31 percent, the 320i was the best-selling 3 Series, followed by the 316 accounting for 27 percent, the 318 with a share of 24 percent, and the 323i with a share in sales of 18 percent. The purchasing motives were the car’s performance in 77 percent of all cases, its handling for 65 percent of the customers, and the special looks of a sporting saloon in 64 per cent of the reasons quoted for buying the car. Most E21 owners were satisfied with their purchase, as almost two-thirds of those surveyed stated that their next car would be another BMW.

Another inquiry showed that drivers of the E21 Series were particularly active motorists by European standards, with more than 60 per cent of those surveyed covering more than 17 000 km (10 500 miles) per year.

In May 1981, six years after the start of production, the millionth 3 Series came off the production line. Worldwide sales of the E21 topped 1.36 million at the end of E21 production in 1982, although the E21 version was not particularly popular in the lucrative United States market.

It was a reasonably popular car in Britain, and helped increase the popularity of "compact executive" models. By the end of its production life in 1983, the E21 was competing fiercely in a market with the likes of the Audi 80 and the new Mercedes-Benz 190E.


The Group 5 version of the BMW 320, introduced in 1977 as a replacement to the already obsolete BMW 3.0 CSL and became nicknamed as the Flying Brick in reference to the blocky bodyshape, was powered by a Formula 2 engine that was tuned to 300 bhp (220 kW) by BMW Motorsport.

Other than the main factory team and Team McLaren who ran the IMSA operation in the US, the car was notably used by the BMW Junior Team, who had the likes of Manfred Winkelhock, Eddie Cheever, and Marc Surer as drivers. They would help to win the 1977 Deutsche Rennsport Meisterschaft and would later go into Formula 1.

The car was also used to win the Macau Guia Race in 1981 and 1982.

Summary: model range

  • 315: The most economical model, introduced to the market in reaction to the second "oil crisis" in late 1979, with a 4-cylinder M10 1.6 L engine and a single downdraft carburetor, 75 bhp (56 kW). More spartan than the other E21 models, it was the last E21 to be built and shared production with the E30.
  • 316: The original 3-series base model with M10 1.8 L engine, 90 bhp (67 kW).
  • 318: Slightly more powerful version (98 bhp (73 kW)) with 1.8 L engine.
  • 318i: An upgraded version of the 316 featuring the M10 1.8 L engine fitted with a Bosch fuel injection system, introduced in 1979 as successor to the carburetted 318.
  • 320: Featured an M10 four-cylinder engine with a Solex 2-barrel downdraft carburetor, 109 bhp (81 kW).
  • 320i: Upgraded version of 320 with an M10 engine; Bosch K Jetronic fuel injection, 125 bhp (93 kW).
  • 320/6: Featured the new BMW 6 cylinder engine, the M20 2.0 L, and a Solex 4-barrel downdraft carburetor; replaced the 320/4 from 1979 on.
  • 323i: Featuring the M20 and Bosch K Jetronic fuel injection, the 323i was the top model of the line, 143 bhp (107 kW), with 4 disk power assisted brakes, power steering as an option, 5 speed economic gearbox after 1980, 5 speed dogleg sport gearbox as an option and limited slip differential (25%) also as an option.


Baur TopCabriolet
  • USA market variants featured different headlights to the European and other export versions.
  • The 320i was available in the United States market and was remarkably different from the European models. Department of Transportation (DOT) safety regulations required larger bumpers, different headlight sets, and DOT marker lamps on the sides.
  • Adapting the engines to meet US exhaust emissions regulations resulted in smaller engine in the 320i (downgraded to 1.8 L) and less horsepower output compared to the European market versions.
  • Companies such as Hartge, Alpina and AC Schnitzer offered aftermarket modifications for the E21. For example, Alpina offered the B6 2.8. Introduced at the IAA in 1978, it was produced from March 1978 until January 1983. Only 533 units were built. The B6 2.8 transplanted the 2.8 L M30 engine from the 528i model into the 323i. Alpina fitted forged Mahle pistons, modified the combustion chambers, and used a Zenith-Pierburg-DL fuel injection system. These modifications raised engine output from 177 bhp (132 kW) to approximately 200 bhp (150 kW).
  • A cabriolet conversion was offered by Karosserie Baur GmbH, based on regular E21 models. The cabriolet conversion was composed of a targa roof and an independent rear soft top. Production of the Baur TopCabriolet began in 1978, and were sold via the BMW dealership network. All TopCabriolets included the BMW warranty. A total of 4,595 vehicles were manufactured before production ended in 1981.


  1. Oswald, Werner (1. Auflage 2001). Deutsche Autos 1945-1990, Band 4. Stuttgart: Motorbuch Verlag. ISBN 3-613-02131-5. 

Further reading

  • Jeremy Walton (2001). BMW 3-Series Collectors Guide: Generation 1 and 2 including M3. Motor Racing Publications. ISBN 1-899870-55-5 (paperback). 
  • R.M. Clarke (1990). BMW Series 3 - 4 Cylinder Cars Gold Portfolio. Brooklands Books. ISBN 1-85520-149-6 (paperback). 

External links