General Motors has announced that a newly redesigned Duramax 6.6L V-8 turbo-diesel will be offered on the 2017 Silverado HD and 2017 Sierra HD. The engine features a new air intake system and an enhanced oiling circuit.
The engine is certified at 445 hp and 910 lb.-ft. of torque—a 19% increase in max torque over the current Duramax 6.6L.The redesigned turbo-diesel’s performance is quieter, with engine noise at idle reduced 38%, according to the automaker.
The Duramax’s new vehicle air intake system drives cool air into the engine, allowing cooler engine temperatures during difficult conditions, such as trailering on steep grades, according Chevrolet. Cooler air helps the engine run better under load, especially in conditions where engine and transmission temperatures can rise quickly.
The engine features an enhanced oiling circuit, with higher flow capacity and a dedicated feed for the turbocharger, which provides increased pressure at the turbo and faster oil delivery. Larger piston-cooling oil jets at the bottom of the cylinder bores spray up to twice the amount of engine oil into oil galleries under the crown of the pistons, contributing to lower engine temperature and greater durability, according to the company.
An integrated oil cooler with 50% greater capacity than the current engine’s ensures more consistent temperatures at higher engine loads.
The Duramax employs a common-rail direct injection fuel system with new high-capability solenoid-type injectors. High fuel pressure of 29,000 psi (2,000 bar) promotes improved fuel atomization for a cleaner burn that promotes reduced particulate emissions, according to Chevrolet. The new injectors also support up to seven fuel delivery events per combustion event, contributing to lower noise, greater efficiency, and lower emissions.
The integrated exhaust brake system makes towing less stressful by creating added backpressure in the exhaust, resulting in negative torque during deceleration and downhill driving, enhancing driver control, and prolonging brake pad life.
The new Duramax 6.6L is capable of running on B20 biodiesel, a fuel composed of 20% biodiesel and 80% conventional diesel.