The Mazda R100 was introduced in June of 1969 and was one of the company's first vehicles to be powered by a rotary engine. The R100 was based on Mazda's RX-85 prototype that had been shown at the 1967 Tokyo Motor Show. Power was from the same twin-rotor 10A engine that could be found in the Cosmo Sport (Mazda's first rotary-powered production car), however it was de-tuned to produce 100 hp (70 kW) - thus the 'R100' name. Even though it had less power, it was still a sporty vehicle due to its low weight. Top speed was in the neighborhood of 180 kph. The modifications made to the rotary engine made it suitable for the wide scale production and helped reduce the production cost. The list of modifications included the use of cast iron in the side housing, new chrome-steel for the eccentric shaft, and less-expensive moulded aluminum for the housings. The exhaust was no longer routed around the rotor housing, although the port configuration remained the same.
The 10A twin-rotor free-revving Wankel motor carried the car to 100 km/h in just 10.8 seconds and had a top speed of around 177 km/h.
The 2+2 coupe was produced from 1968 to 1973. The R100 was known as the Familia Presto Rotary in Japan and was known as the R100 in export markets.
Mazda used the Familia Rotary Coupe in motorsports. It won its first outing at the Grand Prix of Singapore in April of 1969. It was raced on the touring car endurance challenge at Spa, the Spa 24 Hours. The Familia also placed fifth at the Marathon de la Route at Nürburgring in 1969. At the Suzuka All-Japan Grand Cup, it easily outpaced the rest of the field.By Daniel Vaughan | Feb 2017