Diatto Tipo 20 History

Introduced in 1922 and designed by Giuseppe Coda — who had previously been responsible for SCAT racing cars at the Targa Florio — the Tipo 20 was Diatto's most sophisticated road car. Its 2-litre (1,996 cc) four-cylinder engine drove a shaft-driven single overhead camshaft and produced around 40 bhp in standard touring trim, paired with a four-speed gearbox and (unusually for the era) four-wheel brakes on later examples.

In 1922 the Maserati brothers were retained to manage Diatto's racing programme, with Alfieri Maserati as lead development driver. Alfieri substantially revised the engine — raising output to around 70 bhp — and the resultant 20S (short-wheelbase, DOHC, 75 bhp) contested the Targa Florio, the Coppa Florio, and the Circuit of Garda, where Diatto took three consecutive wins in 1922, 1923, and 1924. In 1924, a supercharged 2-litre straight-eight Grand Prix derivative was also developed under Alfieri's direction, though financial strain prevented it from being fully campaigned.

When Diatto's commercial position deteriorated in 1926, Alfieri Maserati departed and, with his brothers, founded Officine Alfieri Maserati in Bologna — using lessons learned on the Diatto eight as the technical foundation for the Maserati Tipo 26. The Tipo 20 touring variants continued in production until around 1928, surviving largely because they were already paid for; the last new cars left the factory before the firm formally ceased automobile production in 1929.