Shortly after the War, Maserati introduced the 'A6' sports racer powered by a brand new 1500cc six cylinder engine. By 1950 it was replaced by a two litre engined version, leaving Maserati customers with no new racing car for the popular and lucrative 1500 sport category. In the following years the class was dominated by German and British alternatives as well as by the OSCAs built by the Maserati brothers. To fill the obvious gap in the line-up Maserati started development of a new 1500 cc engined racer, dubbed the 150S, which they believed would appeal to broad group of privateer racers.
The development of the 150S began back in 1953 when Maserati's chief engineer Giulio Alfieri drew up a new four cylinder engine. In doing so he followed in the footsteps of Ferrari, who had also departed from their original engine configuration of choice to explore the four cylinder route. To cut costs, the alloy 'four' was designed in such a way that it could also be enlarged for a potential two litre racer. Equipped with twin camshafts, twin plugs and a set of twin-choke Webers, the new 1484 cc produced a healthy 140 bhp at 7500 rpm. It was mated to a four speed gearbox.
Again with efficiency in mind a single new chassis was developed, which could be adjusted in length for the various applications. Built up from two tubular longitudinal members with numerous cross braces, the chassis followed a familiar (Italian) pattern. To handle the expected high demand, Maserati commissioned the chassis to be built by Gilco, who also built many of the Ferrari frames. More advanced was the DeDion axle rear suspension, which was carried over from the 250F Formula 1 racer. Even though disc brakes had gradually been introduced by the British manufacturers, Maserati again fitted the tried and trusted drum brakes.
Alongside the two litre 200S and the six cylinder engined, three litre 300S, the brand new 150S was developed in the first months of the 1955. All three cars featured similar Fiandri built roadster bodies and looked ready to take on the world. Production began in June of that year and the first cars were delivered not much later. Jean Behra provided a vital boost to 150S sales by taking a very dominant surprise win at the Nürburgring 500 km in August against very strong competition. Even though the 150S' international racing debut was very convincing, Maserati engineers still found areas that needed improvement.
While the first cars were delivered to the customers, development continued. For the 1956 season a five speed gearbox was readied and many details were changed. In cooperation with with new coachbuilder Fantuzzi a more aerodynamic shape was created with a much longer nose. This new body was fitted across the range. The improvements paid off as the 150S continued to win its class at many occasions and also scored the odd overall victory. Highlights were a scratch win in the 1956 Messina Five Hours and a ninth and second in class at Le Mans.
Towards the second half of 1956 Maserati pulled the plug on the 150S in order to concentrate their waning resources on the development of the larger engined sports racers and the F1 effort. By that time around two dozen complete cars were constructed. The 150S engine was also sold separately and continued to be developed for use both in other racing cars and in power boats. The final evolution of the engine produced a staggering 165 bhp while weighing only 130 kg. It continued to be used until the early 1960s when the 150S engine was used in Formula 1.
Featured is 150S chassis 1659, which was the last car built in 1955. It was sold to the United States and has survived in a remarkable original condition. Owned for many years by an Italian enthusiast, 1659 has been raced at many occasions, while carefully preserving the lovely patina. It is pictured above during one of these outings, at the 2007 Goodwood Revival Meeting.
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