Chassis and engine changes made to the experimental Maserati 4CLs eventually coalesced into the 4CLT, the appended T denoting its tubular chassis.
The improvements in torsional rigidity that the tubular construction brought were required to counteract the increases in torque and power resulting from the twin-supercharger upgrade of the elderly inline-4 engine. Power was up to approximately 260 bhp (194 kW), from the 4CL’s 220. Other changes included the use of roller bearings for the crankshaft, forged (rather than cast) rear suspension components, and the chassis was designed to run with hydraulic dampers from the outset.
The first variant of the 4CLT earned its “Sanremo” nickname from the first race for which it was entered: the 1948 Sanremo Grand Prix. The name stuck, as Alberto Ascari took his 4CLT to victory in its maiden race appearance. A portent of things to come, Villoresi and Reg Parnell won five of the 1948 season’s remaining races.
In the first year of the Formula One World Championship, a Sanremo scored what was to be the Maserati’s best Championship finish, when Louis Chiron took third place at his home Grand Prix: the 1950 Monaco Grand Prix. The last 4CL variant to compete in the World Championship was a 4CLT/48 modified by the Arzani-Volpini team, that failed to even qualify for the 1955 Italian Grand Prix.