General Motors announced this week upgrades to its Duramax 6.6L V-8 turbo-diesel engine to meet government-mandated emissions regulations for diesel engines manufactured beginning in January 2007. To meet the new emissions regulation, the Duramax 6.6L V-8 engine features:

• Additional combustion control, including a more efficient variable-geometry turbocharging system, cooled (enhanced) Exhaust Gas Recirculation (EGR) and closed crankcase ventilation to reduce NOx

• Additional exhaust control, including oxidizing catalyst and new Diesel Particulate Filter (DPF) to reduce soot and particulate matter

• Increased-capacity cooling system

• New engine control software The new Duramax 6.6L V-8 (LMM) engine is offered with increased power and torque for Chevy Kodiak and GMC Topkick medium duty applications. Versions are available with 300 horsepower and 520 lb.-ft. of torque, as well as a new 330-horsepower option with 620 lb.-ft. of torque. Additional details of the Duramax 6.6L V-8 engine's '06 enhancements include:

• Cylinder block casting and machining changes to provide stronger structures with increased reliability and durability

• Revised piston design lowers compression ratio from 17.5:1 to 16.8:1

• Cylinder heads revised to accommodate higher peak cylinder firing pressure

• Maximum injection pressure increased from 23,000 psi to more than 26,000 psi

• Fuel delivered via higher-pressure pump, fuel rails, distribution lines and all-new, seven-hole fuel injectors

• Improved glow plugs heat up faster through an independent controller

• Revised variable-geometry turbocharger is aerodynamically more efficient to help deliver smooth and immediate response and lower emissions

• Air induction system re-tuned to enhance quietness

• EGR has larger cooler to provide for cooler exhaust gases going into the system

• First application of new, 32-bit E35 controller, which adjusts and compensates for the fuel flow to bolster efficiency and reduce emissions