The ALFA 15-20 HP was a car produced by Alfa (who later became Alfa Romeo) between 1914 and 1920.

The model was derived from the 15 HP and was fitted with a 4-cylinder 2413cc engine. The compression ratio was 4,3:1, while the power output from the engine was a maximum of 28 hp at 2400 rpm. The top speed of the vehicle was 100 km/h and could accelerate from 0 to 100 km/h in 100 seconds.

The cars had a total length of 3780 mm, a width of 1400 mm and a mass of 920 kg.

A total of 180 cars were built.

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