A new generation of inline 6 and V8 petrol engines were developed with double-overhead camshafts (DOHC), four valves per cylinder, and new variable valve timing. Mercedes-Benz's first passenger V12 engine was introduced in 1991 in a response to BMW's 750i/750iL (E32). Only 3.5-litre inline 6 diesel engine, OM 603.97x, was carried over from W126 and remained only engine in W140 model range with two valves per cylinder form until its replacement in 1996. The DOHC, four valves per cylinder, and variable valve timing helped increase the horsepower and torque figures without heavy fuel consumption penalty while reducing the emission. All petrol engines were equipped with catalytic converters during the entire W140 model run regardless of where they were sold.