its a mazda engine : from wiki
In Le Mans racing, the first three-rotor engine used in the 757 was named the 13G.
The main difference between the 13G and 20B is that the 13G uses a factory peripheral intake port (used for racing) and the 20B (Three Rotor Engine) uses side intake ports.
It was renamed 20B after Mazda's naming convention for the 767 in November 1987.
The three-rotor 20B-REW was only used in the 1990-1995 Eunos Cosmo. It was the world's first volume production twin-turbo setup featured in both 13B-REW & 20B-REW form. It displaced 1962 cc (three 654 cc rotors) and used 0.7-bar (70 kPa) of turbo pressure to produce 300 horsepower (224 kW) and 407 newton metres (300 ft·lbf).