up from the 45.6 kW/liter for the previous 8-valve Golf GTI engine. The GM Quad 4 multi-valve engine family debuted early 1987. The Quad 4 was the first mainstream multi-valve engine to be produced by GM after the Chevrolet Cosworth Vega. The NA Quad 4 achieved per cubic inch (49.1 kW/liter). Such engines soon became common as Japanese manufacturers adopted the multi-valve concept. Three valves The 1975 Honda Civic introduced Honda's 1.5-liter SOHC 12-valve straight-4 engines. Nissan's 1988–1992 SOHC KA24E engine had three valves per cylinder (two intakes, one exhaust) as well. Nissan upgraded to DOHC after 1992 for some of their sports cars, including the 240SX. In 1988, Renault released a 12 valve version of its Douvrin 4 cylinder 2.0l SOHC. Mercedes and Ford produced three-valve V6 and V8 engines, Ford claiming an 80% improvement in high RPM breathing without the added cost of a DOHC valve train. The Ford design uses one spark plug per cylinder located in the centre, but the Mercedes design uses two spark plugs per cylinder located on opposite sides, leaving the centre free to add a direct-to-cylinder fuel injector at a later date. The 1989 Citroën XM was the first 3-valve diesel-engined car. Four valves Examples of SOHC four-valve engines include the Honda F-series engines, D-series engines, all J-series engines, the R-series engines, the Mazda B8-ME, and the Chrysler 3.5 L V6 engine. The V12 engines of many World War II fighter aircraft also used a SOHC configuration with four valves for each cylinder. The 1993 Mercedes-Benz C-Class (OM604 engine) was the first 4-valve diesel-engined car. Five valves Peugeot had a triple overhead cam five-valve Grand Prix car in 1921. In April 1988 an Audi 200 Turbo Quattro powered by an experimental 2.2-liter turbocharged 25-valve straight-5 rated at 478 kW/650 PS@6,200 rpm (217.3 kW/liter) set two world speed records at Nardo, Italy: 326.403 km/h (202.8 mph) for 1,000 km (625 miles) and 324.509 km/h (201.6 mph) for 500 miles. Mitsubishi were the first to market a car engine with five valves per cylinder, with the 548 cc 3G81 engine in their Minica Dangan ZZ kei car in 1989. Yamaha designed the five-valve cylinder head for the 20-valve 4A-GE engines made by Toyota for use in some Toyota Corolla models in Japan. Yamaha also developed five-valve Formula One engines, the 1989 OX88 V8, 1991 OX99 V12, 1993 OX10 V10 and 1996 OX11 V10, but