DKW 3=6

DKW was one of four companies that had come together in 1932 to form the Auto Union based in Zwickau. The company was effectively refounded in West Germany in 1949, following the loss to the Soviets of its Zwickau assets. Three of the four businesses that had constituted Auto Union before the war seemed unlikely ever to reappear on either side of the Iron Curtain, but starting in 1949 the DKW name was used for the F89 assembled by Auto Union in the west: this was the model replaced by the 3=6.

• The name ‘Sonderklasse’ differentiated the car from the previous model which had been known as the ‘Meisterklasse’. Both names had also been used for commercially successful DKWs in the 1930s. Sonderklasse is a German verbal concatenation that does not translate comfortably into English: it is based on the word ‘Sonder’ of which one translation is ‘special’, linked to the word ‘Klasse’ which translates as ‘class’, or category’.
• 

  1953 DKW 3=6 F91 Cabriolet
  The name ‘3=6’ started out as an advertising slogan, but by the time of the 1955 face lift (for the 1956 model year), the name was to the fore, and the car was advertised as the ‘Large 3=6’ (Großer 3=6) differentiating it from the earlier version which already carried the script ‘3=6’ ahead of the door on its left side. The point of the advertising slogan was to highlight an equivalence between the car's two stroke three cylinder engine and a four stroke six cylinder engine. The underlying logic was that with the two-stroke cycle there is engine power produced by a combustion within each cylinder for every rotation of the crankshaft: with the four-stroke cycle there is power produced by a combustion within each cylinder only for each alternate rotation of the crankshaft. Thus it was asserted that the two-stroke engine was working twice as hard per rotation of the engine. In terms of torque the two-stroke system does indeed appear to have conferred substantial benefits when compared to a four-stroke engine of similar size, but in terms of bhp much of the theoretical energy gain in terms of power output seems to have been dissipated as additional heat which in turn required a larger energy consuming cooling fan, all of which made the arrangement rather noisy when placed just ahead of the driver and front-seat passenger.
• The name F91 was the factory project number of the car. ‘F’ stood for ‘Frontantrieb’ (Frontwheel drive). The F91 was an evolution from the DKW F9 which had been a prototype presented in 1938, planned for production at Auto Union's Zwickau plant from 1940. By 1950 the F9 itself had been made production ready and was being produced as the IFA F9 in Zwickau, so that name was in practice not available to ‘old’ Auto Union's western successor. The DKW F91 was replaced by the F93 followed by the F94, their names also taken from factory project numbers. Because the other names have proved increasingly unfathomable, the names F91, F93 and F94 are the ones commonly used retrospectively.

It was perhaps in recognition that any perceived marketing advantages available from the unconventional namings had been exhausted, that from 1958 the car was sold simply as the DKW 900 (in the USA only), the name being now conventionally based on the car's approximate engine displacement. The successor model, already in production in 1957, also benefited from this less challenging nomenclature.

The DKW F91 on display at the Audi Museum in ingolstadt

The F91 was presented as a two-door saloon with front opening doors which presumably facilitated access. A ‘pillarless’ Coupe version, first seen in 1953, was produced from 1954, as well as a Cabriolet, bodied by Osnabrück coach builders Karmann. In addition there was a three-door estate version, called the ‘Universal’, which continued to be offered unchanged until 1956.

The cabriolet version of the F93 was only available for the 1956 model year.

Modifications came progressively. The coupe version had been launched with a ‘panoramic’ three piece wrap around back window, and in the back end of 1954 a similar wrap-around back window appeared on the two-door saloon. Advertising highlighted such features as a fuel gauge and an interior light that could be set to come on automatically when the door was opened.

1955 saw the launch of the F93 version (for the 1956 model year), also known as the Big DKW 3=6. There were three production series for the Big DKW 3=6:

The panoramic three-piece rear window introduced on the F91

1st series: Model 1956, produced from September 1955 to September 1956 (Chassis number 500 021 to 546 035);

2nd series: Model 1957, produced from October 1956 to September 1957 (Chassis no. 546 036 to 588 410);

3rd series: Model 1958, produced from September 1957 to August 1959 (Chassis number 588 411 to 693 753).

The "Big DKW" F93 featured the same panoramic rear window as the F91, but was a wider car with a number of improvements. This style of bootlid handle was used only for 1956 and 1957 models.

The Big DKW 3=6 shared the 235-centimetre (92.5 in) wheel-base of the F91, but was slightly longer, wider and taller. The track was also increased by 10 centimetres (3.9 in). In place of horizontal metal slats, the new model featured an oval shaped front grill containing five horizontal metal coloured slats. The oval grill was modified again in 1957 when the slats were replaced by a chrome coloured grid design. Inside there were improvements to the instrumentation and the heating, as well as a modest increase in power to 40 bhp.

The DKW Monza which appeared in 1956 was essentially a DKW F93 under its (light-weight plastic) skin.

In 1956, with the introduction of the F94 version of the car, a four-door version finally became available. The four-door saloon's wheel-base was extended by 10 centimetres (3.9 in) over that of the two door: advertising continued to emphasize the DKW's class leading interior spaciousness. 1956 was also the year when the F91 ‘Universal’ estate version (the F91S) was replaced by the F94U Universal: it now incorporated many of features introduced two years earlier on the saloons. The F94 four door saloon and F94 Universal shared the same chassis.

The Brazilian DKW-Vemag Belcar

Auto Union cars were also very popular in South America, where a number of special types based on the DKW 3=6 were manufactured in Brazil under licence by VEMAG from 1956 to 1967. Models sold were the DKW Belcar sedan, the Vemaguet station wagon, and the Fissore, a two-door coupe with a smooth designed body and elegant appointments, which resembled in general terms the DKW F102. The F94 line made by DKW-Vemag was equipped with doors hinged at the front (from 1964) and four headlights (in 1967). Altogether about 109,343 cars were built in Brazil.[22]

The Brazilian version of the DKW F94U Universal, was known as the Vemaguet

The 896 cc three cylinder engine provided at launch a claimed 34 bhp (25 kW). Following the company's pioneering work in the 1930s, the car had a front-wheel drive configuration which meant there was no bulky driveshaft running through the passenger cabin. The water cooled engine was installed longitudinally above the front wheels - the first appearance of the longitudinal "overhung" engine layout which DKW's successor - Audi - still uses to the present day, but the radiator was located not ahead of the engine but between the engine and the passenger cabin.

The gearbox, controlled by a column mounted lever, was a three speed manual system coupled with a free-wheel device: in Autumn 1953 a four speed box was offered as an option. In late 1956, a four speed gearbox became standard, with all but the first gear, fully synchronised. 1956 saw a further transmission advance with the availability of a Saxomat automatic centrifugal clutch on the DKW.

The F93 version launched in 1955 (for the 1956 model year) now boasted power output increased to 38 bhp (28 kW). That increased further to 40 bhp (30 kW) in 1957. The F93 also incorporated a strengthened chassis and improvements to the suspension and braking system.