The Wankel Rotary Engine went the way of many technological innovations and simply didn’t catch on. Despite a Le Mans win in 1991 with the 787B, the Rotary engine in production cars ended with the Mazda RX-8(2001-2012). Known for intense power-to-weight ratios, Wankel engines were known for reliability, if also for poor fuel economy.
The 1991 Le Mans 24 hour victory stands as the only victory for a Japanese marque and also the only victory by a non-reciprocating engine design.
Developed from a 1927 patent, the Wankel engine had two designs. The two engineers at the Germans NSU company developed different variations. Felix Wankel, the patent holder developed the more complicated DKM desing, while Hanns Dieter Paschke developed the KKm design. The mroe naturally balanced and powerful DKM design had mroe parts, and had to be taken apart to access the spark plugs. The simpler KKM design was adopted by NSU and as such the “Paschke” rotary engine is a more applicable term, despite Wankel’s initial patent.
The high rpms acheived by Wankel rotary engines made them incredibly unique. Only motorcycle engines routinely acheived higher rpms.
Hondas’s first prodcution car, the S500 borrowed extenisvely from Honda’s motorcycle genes. Released in 1963 it featured a dual overhead cam straight-4with four carburetors and a 9500 rpm redline. At 531 cc it produced 44 hp at 8000 rpm. Weighing just 1500 lb (680 kg), the tiny S500 could hit 80 mph (129 km/h). The tiny sports car wighed less than 700 kilogram meaning that the little rev-happy engine was adequate for daily driving.
The Mazda Rotary Saga began in 1971 with the R100, and ceased in 2012 with the last RX-8. The failure of the Rx-8 to meet European emission standards in Europe meant the end of the rotary engine.
The Rx-8’s small 1.3 L Renesis Wankel Rotary Engine continued the legacy of the Rx-7 of lightweight aluminum engines, with fast response and quick revving tendencies. A redline of 9,000 meant that the 1.3L engine was anything but fuel-efficient. Consuming a litre of oil /1000 miles was also part of the compromise with the rotary engine.
The 1999 Honda S2000 was the spiritual successor to the S500/600 and with its lightweight design and high revving small displacement engine. The initial release featured a 9000 rpm redline, but later updates decreased it to 8000 because of the longer travel of the pistons. Peak power was 237 hp at 7800 rpm.