automatic transmission was optional. In September 1982, North American and Japanese market models received a major facelift, as per the models sold in the rest of the world. 635CSi In November 1984, for the 1985 model year, the 633CSi was replaced by the 635CSi for the North American Market. This model uses the M30B34 engine, which produces and at 4,000 rpm. An L6 "luxury edition" version of the 635CSi was available in North America for the 1987 model year. The L6 featured leather headliner and trim and an automatic gearbox. In 1988, the engine was upgraded to the M30B35. This engine has a capacity of 3.4 Litres (despite the model code and the "3.5" inscribed on the intake manifold) and produces and torque. This upgraded engine resulted in catalytic converter equipped United States models offering similar performance to European models. Self-leveling rear suspension was added to the 635CSi and M6 features list. M6 In 1987, North America and Japan received their equivalent of the M635CSi, called simply the M6. The main difference between the M6 and its European counterpart, is that the S38 engine is used instead of the M88. Compared with the M88, the S38 has a catalytic converter, the compression ratio reduced to 9.8:1, a double row timing chain, a shorter camshaft duration and a simplified exhaust manifold. The power output for the North American E24 M6 is , which is less than the European M635CSi. Standard equipment on the United States market M6 cars included many features which were optional on the European cars, including heated power seats, self-leveling rear suspension, beverage chiller (cooled by an air-conditioning system) between the rear seats, air-conditioning vents for rear seat occupants, sunshade for rear occupants and an 8 speaker premium sound system. Motorsport In 1982, the European Touring Car Championship transitioned to Group A regulations, prompting BMW to move from the 3.0 CSL to the 635 CSi. BMW Motorsport produced approximately 50 competition chassis between 1983 and 1985. Achievements in championships and series: European Touring Car Championship (Group A); 3 titles (1981, 1983 and 1986) Deutsche Tourenwagen Meisterschaft; 1 title (1984) Belgian Touring Car Championship (Group N); 1 title (1984) Australian Touring Car Championship; 1 title (1985) Australian Endurance Championship; 2 titles (1985 and 1986) Australian Manufacturers' Championship; 1 title (1985) AMSCAR Series; 1 title (1985) European Hill Climb Championship; 1 title (1985) New Zealand Touring Car Championship; 2 titles