HB series Cosmo

Like the 12A SPI engine, this 13B was "6 port" inducted. How did it work? Anyone familiar with the operation of a rotary engine would know that during normal driving only two “primary ports” are used for the gas flow to the engine. The size of the ports is proportional to the power/torque the engine produces aswell as it’s fuel economy. Mazda’s solution was to design a pair of very small primary ports which resulted in the rotaries excellent economy.

Now the 13B engine was achieveing respectable fuel economy. It's larger capacity ensured good torque in the mid range level, Exactly were Mazda wanted it at 3000 rpm.

For pure marketing reasons, Mazda only allowed the 4 speed auto tranmission behind the 13B. (no manual option) This was due in part to reduce the high performance image & create a more genuine alternative to the piston option as an everyday useable car. The 13B option was dropped in late 86 when the 13B turbo optioned HC Luce came on line in 87.