The Duramax LLY was introduced in 2004 to replace the popular LB7. Like the LB7, the LLY utilizes a high pressure common rail direct injection system. The LLY was General Motors' first attemp at implementing emission controls on a diesel engine to meet stricter emissions requirements in the future. The LLY adopted a variable geometry turbocharger (VGT) and exhaust gas recirculation (EGR) system to help reduce emissions. Huge changes to the LLY debuted in 2006, but the engines were mechanically identical.
2004.5 - 2006
403 cubic inches, 6.6 liters
90 degree V8
17.5:1 (16.8:1 in 2006)
• Garrett variable geometry turbocharger (VGT) • air to air intercooler
OHV, 4 valves per cylinder
• Direct injection • Bosch high pressure common rail, CP3 injection pump • 23,000 psi max injection pressure