In 1930, the Gran Sport was Alfa Romeo’s fourth series 6C and their most capable sports-racing car. Fitted with competition bodywork, Tazio Nuvolari drove one to overall victory at the IV Coppa delle Mille Miglia and Giuseppe Campari repeated the feat in 1931 with his.

Like all of the 6C series, the Gran Sport benefited from Vittorio Jano’s excellent engineering and design principles. It was an updated version of the 6C 1750 Super Sport from 1929 which had similar specification. New to the Gran Sport was shorter wheelbase that was reduced 50mm with shorter rear leaf springs. The slightly smaller fuel tank was repositioned behind the rear wheels and the battery box was moved from the fender to inside the cockpit behind the front seats.

One of the largest changes introduced with the 4th series Gran Sport was a modified Roots-type supercharger that operated at engine speed and with larger rotors. With no step gear, it ran slower and therefore spun the opposite direction which relocated the carburetor from the left to the right side of the manifold.¹

With its supercharger, the 1750 Gran Sport was an invincible race car, one with ample torque for its small chassis. The supercharger was a necessary ingredient that allowed the 1750 to be light, yet powerful, a characteristic that contributed to less driver fatigue and less stress on individual components. It was somewhat rare on sports cars of the period but was proven effective with the 1929 Super Sport. For the Gran Sport the engines main bearings also increased in size.¹

The highly developed engine produced by Vittorio Jano sat in a chassis “similar to Ansaldo, Bianchi, Diatto and OM.” These cars embodied the functional simplicity of sports cars in the period which used pressed steel frames, wire wheels, mechanical brakes and solid axles.¹

At the 1930 Mille Miglia, Tazio Nuvolari 1750 would become known for an epic duel between Nuvolari and Varzi. In the last 600km, Nuvolari overtook Varzi in the early morning with his 1750’s headlights switched off and continued on to win the race by finishing over 7 minutes ahead. After 16 hours of racing, they both had outpaced sole Mercedes-Benz SSK of Rudolf Caracciola and the three-liter OM.²

Later victories included the 1930 24 Hours of Spa, 1930 Tourist Trophy and numerous other Road Races and Hillclimbs.

The 1750 was produced in six series and became more sophisticated from 1929 to 1933. In total, about 2500 cars were completed and they became the quintessential model for both the amateur and professional drivers. Available in several configurations, most cars were sold as rolling chassis and bodied by coachbuilders such as Zagato, Touring and James Young.

In total, over 250 Gran Sports were made and they provided launch points for several firms, including Zagato who bodied most of them, and Scuderia Ferrari, who bought and raced them. Several cars were fitted with experimental engines from the factory: some used a full eight main bearings instead of five and others were cast in aluminum with pressed-in steel cylinder liners.¹

By 1931, the Gran Sport was replaced by the eight cylinder 8C 2300. Engines aside, both cars shard common design elements.

Sources & Further Reading

1.Fusi, Luigi & Royt Slater. The 6C 1750 Alfa Romeo. Macdonald: 1968.
2. Curami, Andrea. Alfa Romeo & Mille Miglia.Giorgio Nada Editore Srl: 2010.