GM Family Z engine

Family Z is a turbocharged common rail diesel engine produced by General Motors Korea since 2010. It replaced VM Motori RA 420 diesel engine in a number of GM applications, such as the diesel versions of vehicles sold as Chevrolet made for North America, Daewoo made for Korea, Opel made for Europe and Holden made for Australia.

The engine features chain driven DOHC valvetrain with hydraulic tensioners, twin balance shafts in the oil pump and electronically controlled variable-geometry turbocharger; the common rail system operates at pressures of up to 1800 bar, maximum in-cylinder pressure is 180 bar, improving on power and torque. Compression ratio is 16.5:1.

For 2012, compression ration is reduced to 16.3:1, and a new intake port increases air flow and swirl control, improving nitrogen oxide emissions and performance.