BMW 3/20
1933 BMW 3/20 type AM 4 |
|
| Manufacturer | BMW |
|---|---|
| Production | 1932–1934[1] |
| Assembly | Eisenach, Germany |
| Predecessor | BMW 3/15 |
| Successor | BMW 309 |
| Layout | FR layout |
| Engine | 788 cc (48.1 cu in) OHV straight-4[1] |
| Wheelbase | 84.6 in (2,149 mm) |
| Designer | Alfred Böning |
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).[1] 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.[2]
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.[2]. 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.[1]
Journalist and engineer Josef Ganz, who had criticized the 3/15 DA-4's suspension system in the magazine Motor-Kritik,[3], was contracted in July 1931 as a consultant in the design of the 3/20 AM-1.[citation needed]
Four versions of the 3/20 were built: AM 1, AM 2, AM 3 and AM 4, where AM denoted Automobil München.[1]
[edit] Notes
[edit] References
- Norbye, Jan P. (1984). BMW - Bavaria's Driving Machines. Skokie, IL: Publications International. ISBN 0-517-42464-9.
- "BMW's Early History". unixnerd.demon.co.uk. http://www.unixnerd.demon.co.uk/history.html. Retrieved 2008-02-18.
- "Die Schwingachse des Kleinen" (in German). Motor-Kritik (3). February 1931.
| BMW road car timeline, 1920s–1940s — next » | ||||||||||||||||||||||||||||||||||||||||
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| Type | 1920s | 1930s | 1940s | |||||||||||||||||||||||||||||||||||||
| 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | |||||||||||
| Straight-4 | Dixi 3/15/Dixi 3/15 DA/Dixi 3/15 DA1/ | 3/15 DA2/ 3/15 DA4 | 3/20 | 309 | ||||||||||||||||||||||||||||||||||||
| Straight-6 | 303 | |||||||||||||||||||||||||||||||||||||||
| 315, 319 | 329 | 320 | 321 | 321 | ||||||||||||||||||||||||||||||||||||
| 326 | 326 | |||||||||||||||||||||||||||||||||||||||
| 327 | 327 | |||||||||||||||||||||||||||||||||||||||
| 335 | ||||||||||||||||||||||||||||||||||||||||
| Sports car | DA-3 Wartburg | 315/1, 319/1 | 328 | |||||||||||||||||||||||||||||||||||||
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