General Motors is bestowing a basically all-new Duramax 6.6-liter diesel engine on both the 2017 GMC Sierra HD and its twin the 2017 Chevrolet Silverado HD. Both automakers made the dual announcement at truck central this week at the State Fair of Texas.
Here’s what is brings to the table. The next-generation redesign offers more horsepower and torque. It’s up to 445-horses and 910 pound-feet, a 19 percent increase in max torque over the current Duramax. It’s quieter, too. Engine idle noise is cut by around 38 percent.
The engine is basically brand new. It only shares the bore and stroke dimensions with the current one and incorporates a new GM-developed control system. What hasn’t changed it the Duramax’s signature low-rpm torque production. It still offers 90 percent of peak torque at a low 1,550 rpm and sustains it through 2,850 rpm.
“Nearly everything about the Duramax is new, designed to produce more torque at lower rpm and more confidence when trailering or hauling,” said Gary Arvan, chief engineer. “You’ll also notice the refinement improvements the moment you start the engine, and appreciate them as you cruise quietly down the highway — with or without a trailer.”
The engine also features new, stronger cylinder block and cylinder heads, increased oil- and coolant-flow capacity and an integrated oil coiler with 50 percent greater capacity than the current engine’s. There is also a new electrically electronically controlled turbocharging system and we can thank a new damped steel oil pan for helping make the engine run quieter.
Another key component is a new, patent-pending air intake system. It gives both the Sierra HD and Chevy Silverado HD a bold hood scoop. As most air intakes do, it drives cool, dry air into the engine to help it stay cool while going up steep grades. As we know, cooler air helps engines run better under load especially when you’re dealing with conditions where engine and transmission temps can rise quickly.
The engine is being built at GM’s plant in Ohio.
Photo Credit: Amy Plemons/Car Pro / Photo Credit: GMC/Chevrolet