Mazda Cosmo Sport 110S (L10B)
The L10B series of the Mazda Cosmo Sport was an evolution of the groundbreaking original, featuring a longer wheelbase, more powerful engine, and improved refinement. Produced from 1968 to 1972, it represented the matured version of Mazda's rotary technology showcase.
The twin-rotor 10A engine was upgraded to produce 128 horsepower at 7,000 rpm — an 18 hp increase over the original L10A. The improvements came from revised porting, a larger carburetor, and optimized ignition timing. The engine retained its characteristically smooth, vibration-free operation and willingness to rev, with the distinctive rotary whir rising in pitch as the tachometer climbed.
The wheelbase was extended by 150mm to 2,350mm, improving straight-line stability and rear passenger accommodation (though the Cosmo remained fundamentally a two-seater with occasional use rear space). The longer body also provided slightly improved luggage capacity. A five-speed manual gearbox was available for the first time, complementing the engine's broad powerband.
The L10B retained the elegant coupe styling of the original but with subtly revised details. The overall design — with its flowing fenders, low hood, and fastback profile — continued to look exotic and purposeful. The interior was upgraded with improved seats, better sound insulation, and a more comprehensive instrument panel.
The chassis received similar improvements. The front suspension retained its double-wishbone and coil spring arrangement, while the rear live axle benefited from a wider track and revised spring rates. Front disc brakes and rear drums provided adequate stopping power for the car's modest weight of approximately 940 kg.
The L10B was produced in larger numbers than the original — 1,176 units versus 343 for the L10A — but it remains an extremely rare car. Its significance as a continuation of Mazda's rotary engine program, combined with its elegant design and limited production, makes it one of the most collectible Japanese cars of any era.
All L10A concerns apply. The five-speed gearbox, if fitted, is desirable. Rotary engine apex seal condition is critical — have a specialist perform a compression test. Body panels are shared with L10A but both are extremely scarce. Japanese-market cars in original condition are most prized. Documentation and history significantly affect value.
The L10B series was produced from July 1968 to 1972 at Mazda's Hiroshima factory. Total L10B production was 1,176 units, making the total Cosmo Sport production across both series 1,519 units.