In August 1969, Mazda entered three racing versions of the R100 (known as the Familia Rotary Coupe in Japan) in the Belgian Spa-Francorchamps 24-hour race. The team prioritized engine durability, and limited engine speeds down from 9000 to 8500 rpm. With maximum power output set to 187bhp at 8500 rpm, the cars were expected to go the distance.
  After suffering from oil trouble during the race, Mazda finished 5th and 6th overall. Soon after, three R100 models with the racing type 10A engine (178bhp/8000rpm) were entered in the Marathon de la Route at the Nurburgring.
  One car developed a leak in the fuel tank and ran dry. The second span out in the rain and had to retire. The last R100 suffered a damaged exhaust bracket due to thermal shock from the rain, but still managed to finish 5th overall.