|1933 to 1934|
|Assembly||Eisenach, Thuringia, Germany|
|Body and chassis|
|Class||Small family car|
|Body style||303, 315, 319: 2-door saloon, 2-door cabriolet
329: 2-door or 4-door cabriolet
|Engine||BMW M78 OHV I6
303: 1,173 cc (71.6 cu in), 30 PS (22 kW; 30 hp) at 4000 rpm
|Transmission||4-speed manual, synchromesh on 3rd and 4th|
|Wheelbase||2,400 mm (94.5 in)|
|Length||3,900 mm (153.5 in)|
|Width||1,440 mm (56.7 in)|
|Height||1,550 mm (61.0 in)|
|Kerb weight||1,808 lb (820 kg)|
The BMW 303 was a small family saloon produced by BMW in 1933 and 1934. It was the first BMW motor car with a six-cylinder engine and the first BMW motor car with the "kidney grille" associated with the brand. The platform developed for the 303 was used for several other BMW cars, including the BMW 309, a four-cylinder version of the 303, the BMW 315, a 1.5 litre version of the 303 which replaced it in 1934 and was built until 1937, the BMW 319, a 1.9 litre version of the 303 produced alongside the 315 from 1935 to 1937, and the BMW 329, a development of the 319 with styling based on the newer, larger BMW 326, that briefly replaced the 319 in 1937.
The 303 platform was also used for the BMW 315/1 and BMW 319/1. These were high-performance versions of the 315 and 319 respectively, with tuned engines and lightweight roadster bodywork. The 315/1 and 319/1 were replaced by the BMW 328 in 1936.
BMW 303 interior view
Design, engineering, and styling
Chassis and suspension
Upon its introduction in 1933, the 303 was the largest car BMW had made. The wheelbase of the 303 was 2,400 millimetres (94.5 in), an increase of 300 millimetres (11.8 in) over the 3/20. The track, 1,150 millimetres (45.3 in) at the front and 1,220 millimetres (48.0 in) at the rear, was also wider than the 3/20's 1,100 millimetres (43.3 in) front and rear. Unlike the 3/20's backbone chassis, the 303 had a ladder frame made from tubular side members and box-section cross members.
The independent front suspension used a transverse mounted leaf spring mounted above the wheel centre line. The hubs were located with the spring mounts at the top and control arms at the bottom. The rear suspension used a live axle on semi-elliptic leaf springs, a conventional system neither as advanced nor as troublesome as the 3/20's swing axles.
The 303 was the first German car in its size and price class to have automatic "one-shot" chassis lubrication. Each wheel had a drum brake; all four were operated through the pedal using rods and levers, while the rear brakes were also operated by cables from the handbrake lever.
The 303 was the first BMW car to use a straight-6 engine. The M78 1182 cc six-cylinder engine was developed from the four-cylinder engine used in the 3/20. The engine had the same bore and stroke as the four, but the bore spacing was increased to allow for further increases in bore and to provide for crankshaft bearings between the ends of the crankshaft. The crankshaft ran in four plain bearings.
BMW 303 engine view
The 303 was the first BMW to use the 'kidney grill' which has since become a defining feature of the company's models.
Two-door saloon and cabriolet bodies were manufactured, at first by Daimler-Benz's coachworks in Sindelfingen, and later by Ambi-Budd in Berlin. Ambi-Budd would also offer a two seat sports cabriolet for the 303.
At the time it was being made, the 303 was the least expensive six-cylinder car in Germany. However, it was considered underpowered, with a top speed of 56 miles per hour (90 km/h). The combination of soft spring rates at the front and hard spring rates at the rear caused understeer, body roll, and a generally unsettling pitching movement. 2300 BMW 303s were produced up to 1934, when the 303 was replaced by the 315.
BMW 303 side view