The Mazda Wankel engines (a type of rotary combustion engine) are family of car engines derived from experiments in the early 1960s by Felix Wankel, a German engineer. Over the years, displacement has been increased and turbocharging has been added.
Wankel engines can be classified by their geometric size in terms of radius (rotor center to tip distance, also the median stator radius) and depth (rotor thickness), and offset (crank throw, eccentricity, also 1/4 the difference between stator's major and minor axes). These metrics function similarly to the bore and stroke measurements of a piston engine. Displacement is 3√3radius·offset·depth, multiplied with the number of rotors (note that this only counts a single face of each rotor as the entire rotor's displacement). Nearly all Mazda production Wankel engines share a single rotor radius, 105 mm (4.1 in), with a 15 mm (0.6 in) crankshaft offset. The only engine to diverge from this formula was the rare 13A, which used a 120 mm (4.7 in) rotor radius and 17.5 mm (0.7 in) crankshaft offset.
Mazda rotary engines have a reputation for being relatively small and powerful at the expense of poor fuel efficiency. They are starting to become popular with kit car builders, hot rodders and in light aircraft because of their light weight, compact size, and tuning potential stemming from their inherently high power to weight ratio[citation needed].
In auto racing, the displacement of a Wankel engine is usually doubled for classing purposes. For calculating taxes in Japan, the displacement of Wankel engines is defined as the equivalent of 1.5 times the nominal displacement, so the 1300 cc 13B engines are taxed as 1950 cc.
When Wankel engines became commonplace in motor sport events, this created the problem of accurate representation of each engine's displacement, for the benefit of competition. Rather than force the majority of participants (driving piston engine cars) to half their quoted displacement (likely resulting in confusion), most racing organizations simply decided to double the quoted displacement of Wankel engines.
The 13A was designed especially for front wheel drive applications. It had two 655 cc rotors for a total of 1310 cc. This was the only production Mazda Wankel with different rotor dimensions: Radius was 120 mm (4.7 in) and offset was 17.5 mm (0.7 in), but depth remained the same as the 10A at 60 mm (2.4 in). Another major difference from the previous engines was the integrated water-cooled oil cooler.
The 13A was used only in the 1969–1972 R130 Luce, where it produced 126 hp (94 kW) and 172 Nm (126 ft·lbf). This was the end of the line for this engine design: the next Luce was rear wheel drive and Mazda never again made a front wheel drive rotary vehicle.
Applications:
1970–1972 Mazda R130
