The Delage 15 S8 was a racecar built between 1926 and 1927, only 4 cars were made.
In an attempt to prevent the racing cars from reaching terminal velocity the displacement was lowered to 1.5 litres and a minimum weight of 600 kg. While a two-seater body was still mandatory, the riding mechanic was no longer required.
Encouraged by Lory's achievements, Delage commissioned him to build a completely new Grand Prix car for the 1926 season. He picked the very popular straight eight layout with twin, gear driven cams.
To get the most out of the engine two Superchargers were installed next to the engine. The beautiful engine produced a staggering 170 bhp. Directly bolted onto the engine was a five speed gearbox, creating an unusually long drivetrain.
Installed in the simple ladder frame, only a very short prop-shaft was required to connect the gearbox to the differential. Dubbed the 15 S8 for obvious reasons, the new Delage was very low and sleek.
Delage fielded three 15 S8s for every race. Despite the complexity of the engine, the racers were fairly reliable from the get-go. At the new car's debut in the Spanish Grand Prix, the cars finished in second, fourth and sixth among strong competition from Bugatti and Talbot. Less than a month later in the British Grand Prix at Brooklands (with chicanes), the Delage 15 S8 scored its first major victory and this time Delage was able to continue racing their winning machine for once. Over the winter a variety of minor modifications were carried through on the four cars constructed to perfect the car's handling and performance. The most notable changes were installation of single front-mounted Supercharger and the switch of the exhausts from the right side to the left side of the engine. Although the engine's output did not increase, the sum of these changes brought even more success to Delage. With Robert Benoist winning all five of the Grands Prix in 1927, the company won the much coveted constructor's World Championship.
All this success came at a price though and at the end of the very successful season, a virtually bankrupt Delage was forced to withdraw from racing and concentrate on building new road cars. It was by no means the end of the racing career for the four 15 S8s, which continued to see active service for many years to come in the hands of privateers. In the mid-1930s it proved to be the perfect weapon in the very popular voiturette class. In the hands of Richard Seaman, the then ten year old Delage regularly beat the much more modern Maseratis and ERAs in 1936.
Three of the four examples constructed in 1926 survived.