(September 29, 2016) DALLAS — GMC today announced the redesigned Duramax 6.6L V-8 turbo-diesel offered on the 2017 Sierra HD. This next-generation redesign offers more horsepower and torque than ever — an SAE-certified 445 horsepower and net 910 lb.-ft. — to enable easier, more confident hauling and trailering.

Along with a 19 percent increase in max torque over the current Duramax 6.6L, the redesigned turbo-diesel’s performance is quieter and smoother, for greater refinement. In fact, engine noise at idle is reduced 38 percent.

“With nearly 2 million sold over the past 15 years, customers have forged a bond with the Duramax diesel based on trust and capability,” said Dan Nicholson, vice president, Global Propulsion Systems. “The new Duramax takes those traits to higher levels.”

The new Duramax 6.6L shares essentially only the bore and stroke dimensions of the current engine and incorporates a new, GM-developed control system. The Duramax’s signature low-rpm torque production hasn’t changed and 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.”

Additional highlights include:

    New, stronger cylinder block and cylinder heads
    New, stronger rotating and reciprocating assembly
    Increased oil- and coolant-flow capacity
    New EGR system with single cooler and integrated bypass
    New electrically actuated/electronically controlled turbocharging system
    All-new advanced solenoid fuel system
    All-new electronic controls
    New full-length damped steel oil pan that contributes to quietness
    New rocker cover/fuel system acoustical treatments
    B20 bio-diesel compatibility
    SAE-certified 445 net horsepower (332 kW) at 2,800 rpm
    SAE-certified 910 net lb.-ft. of torque (1,234 Nm) at 1,600 rpm

A new, patent-pending vehicle air intake system — distinguished on the Sierra HD by a bold hood scoop — drives cool, dry air into the engine for sustained performance and cooler engine temperatures during difficult conditions such as trailering on steep grades. Cooler air helps the engine run better under load, especially in conditions where engine and transmission temperatures can rise quickly. That allows the Duramax to maintain more power and vehicle speed when trailering in the toughest conditions.

The intake design is another example of the advanced integration included in the 2017 Sierra HD that makes it over-the-road capable.