The Type 46 was one of Ettore Bugatti's personal favourites despite, or perhaps because of, its uncompromising design priorities. While rivals sought a smooth, refined ride, Bugatti engineered the Type 46 around a gearbox mounted in unit with the live rear axle, placing the transmission far from the driver. This arrangement resulted in high unsprung weight and a relatively harsh ride by the standards of a large luxury car, but it simplified the driveline and reflected Bugatti's characteristic indifference to comfort when it conflicted with mechanical elegance.
The Type 46 used a 5.4-litre (5359 cc) straight-eight engine with three valves per cylinder driven by a single overhead camshaft, producing a reported 140 hp (104 kW). Bore and stroke measured 81 mm by 130 mm — undersquare in the Bugatti tradition. The car rode on a long 138-inch (3505 mm) wheelbase and weighed approximately 2500 lb (1134 kg). Production ran from late 1929 through 1936, with 400 examples built in total.
A supercharged variant, the Type 46S, was introduced in 1930. Fitted with a Roots-type blower, it developed 160 hp (119 kW) — a modest gain that failed to transform the car's character. Only 18 supercharged examples were completed, reflecting limited market appetite for the blown version.
The Type 50 was the sporting evolution of the Type 46 platform. It rode on a shorter 122-inch (3099 mm) wheelbase and used a revised 5.0-litre (4972 cc) engine with squarer dimensions at 86 by 107 mm. Crucially, the Type 50 engine adopted twin overhead camshafts operating two valves per cylinder, a significant departure from the single-cam Type 46 unit. Power climbed to 225 hp (167 kW). Many cars received landaulet roofs and Bugatti's characteristic two-tone paint schemes.
The Type 50 Touring was a sedan variant that retained the longer 138-inch wheelbase of the Type 46 while adopting the Type 50's 5.0-litre twin-cam engine, tuned for torque rather than peak power at 200 hp (149 kW). Combined production of the Type 50 and Type 50T reached 65 cars between 1930 and 1934.
The Type 50B was a full racing derivative sharing the 5.0-litre two-valve engine but fitted with forced induction to produce 470 hp (350 kW). Used by the Bugatti racing team from 1937 through 1939, the Type 50B represented the ultimate expression of the platform in competition. Its engine found an unusual second application in the Bugatti P100 aircraft, where a pair of Type 50B units were installed with specially cast magnesium crankcases.
The Type 46 family bridged Bugatti's single-cam touring tradition and the twin-cam performance engineering that characterised the marque's 1930s racing cars. The Type 50B's repurposing in the Bugatti P100 underscored how the fundamental engine design was robust enough for aviation use. Though the high unsprung weight of the rear-mounted gearbox drew criticism, Ettore Bugatti's personal attachment to the Type 46 ensured the model remained in production across an unusually long seven-year span.