The BMW 315 was a middle sized saloon produced by BMW from 1934 to 1937. It was based on the BMW 303. It differed from the 303 mainly with its larger engine, with increases in both the bore (to 58 mm (2.3 in) from 56 mm (2.2 in)) and the stroke (to 94 mm (3.7 in) from 80 mm (3.1 in)).
A total of 9,765 BMW 315s were built, including two-door saloon cars, touring cars, convertibles, sport convertibles, and 315/1 roadsters.
The BMW 315/1 was a sports car based on the 315 saloon. It used the same chassis as the 315 saloon and had an engine of the same displacement. However, with compression ratio increased to 6.8:1 from 5.6:1 in the saloon, and with the use of three Solex carburetors, power increased to 40.6 PS (29.9 kW; 40.0 hp) at 4300 rpm, while the roadster bodywork reduced kerb weight to 750 kg (1,653 lb).
Production of the 315/1 ended in 1936. 242 examples were built.
BMW 319 and 319/1
The BMW 319 and 319/1 were introduced in 1935. They differed from the 315 and 315/1 mainly in that the dimensions of the engines were increased. The new, larger engine had a bore of 65 mm (2.6 in), and a stroke of 96 mm (3.8 in), resulting in a displacement of 1,911 cc (116.6 cu in). This resulted in an increase in power to 45 bhp (33.6 kW) at 3750 rpm in the base 319 and 55 bhp (41.0 kW) at 4000 rpm in the 319/1 roadster The kerb weight of the 319 was 850 kg (1,874 lb), and the fuel capacity was 40 L (11 US gal; 9 imp gal).
A total of 6,646 BMW 319s of all types were built by the end of production in 1937. 102 of these were 319/1 roadsters.
The BMW 329 replaced the BMW 319 in early 1937. The 329 was basically a 319 with the front bodywork and fenders from the BMW 326. The 329 was available only as a convertible, with either two or four doors. The 329 was replaced by the 326-based BMW 320 later in 1937.