|(1932 to 1934)|
|Also called||AM-1, AM-2, AM-3, AM-4|
|Body and chassis|
|Body style||four seat saloon
four seat cabriolet
two seat convertible coupé
|Engine||788 cc (48.1 cu in) OHV straight-4|
|Wheelbase||2,150 mm (84.6 in)|
|Length||3,200 mm (126 in)|
|Width||1,420 mm (56 in)|
|Height||1,550 mm (61 in)|
|Kerb weight||650 kg (1,433 lb) with saloon body|
The BMW 3/20 PS was the first BMW automobile designed entirely by BMW. It was manufactured from 1932 to 1934, replacing the 3/15 model that was initially an Austin 7 manufactured under licence from the Austin Motor Company.
The engine used in the 3/20 was based on the Austin Seven engine used in the 3/15, but its crankshaft ran in plain bearings instead of roller bearings and had an 80 mm (3.1 in) stroke, generating a displacement of 788 cc (48.1 cu in). The new engine design also had a water pump and an overhead valve cylinder head. These design changes caused the engine to generate 20 hp, but did not change the taxable horsepower rating of 3 PS, thus giving the model designation 3/20.
The 3/20 was larger than the 3/15, with an 84.6 in (2,149 mm) wheelbase and a body 3 in (76 mm) lower than the 3/15. The 3/20 used a backbone frame unrelated to the 3/15's Austin Seven "A" frame. It inherited the 3/15 DA-4's independent front suspension and added a swing axle independent rear suspension, using a transverse leaf spring similar to that used at the front. The standard bodies for the car were built by Daimler-Benz in Sindelfingen.
Journalist and engineer Josef Ganz, who had criticized the 3/15 DA-4's suspension system in the magazine Motor-Kritik, was contracted in July 1931 as a consultant in the design of the 3/20 AM-1.
Four versions of the 3/20 were built: AM 1, AM 2, AM 3 and AM 4, where AM denoted Automobil München.
1932 BMW 3/20 two seat convertible coupé