The Mazda RX-7, also called the Savanna and Efini RX-7, was a sports car that began production in 1978. It featured a unique twin-rotor Wankel rotary engine and a sporty front-midship, rear wheel drive layout. The RX-7 was a direct replacement for the RX-3 and subsequently replaced all other Mazda rotary cars with the exception of the Cosmo. The Series 1, produced in 1979 and 1980, is referred to as the "SA22C". The relatively light Wankel engine was situated slightly behind the front axle. The Wankel rotary engine, invented by German engineer Felix Wankel, uses a rotor instead of reciprocating pistons. Wankel first conceived his rotary engine in 1954. Mazda's first Wankel-engined car was the 1967 Mazda Cosmo.
1980 Mazda RX-7
Wankel engines are considerably simpler and contain far fewer moving parts. They have no valves or complex valve trains. In addition, since the rotor is geared directly to the output shaft, there is no need for connecting rods, a conventional crankshaft, or crankshaft balance weights. The elimination of these parts makes the Wankel engine much lighter, typically half that of a conventional engine with equivalent power. The rotary engine also completely eliminates the reciprocating mass of a piston engine with its internal strain and inherent vibration. The engine is constructed with an iron rotor within a housing made of aluminum. This feature ensures that even if severely overheated, the Wankel engine can not seize. The RX-7’s 100 horsepower engine derived from the tiny 1146cc Wankel produced 8.5-second 0-to-60-mph time and a top speed of 124 mph.