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 uses side intake ports.

It was renamed 20B after Mazda's naming convention for the 767 in November of 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 (around 10psi)of turbo pressure to produce 300 hp (224 kW) and 300 ft.lbf (402 Nm). It was at the time the highest torque output engine of any Japanese vehicle manufacturer.