How Much Power And Torque Will GM’s New L5P Duramax Make?


General Motors is set to introduce a new 6.6-liter V-8 Duramax Turbo-Diesel engine for its 2017 model year heavy duty trucks — the 2017 Chevrolet Silverado HD and 2017 GMC Sierra HD. Assigned production code L5P, the new B20-compatible motor works in conjunction with the trucks’ new air intake system while remaining mated to the familiar Allison 6-speed automatic transmission (which itself might also be getting a few improvements for MY 2017). What we don’t know, though, is most important: how much power and torque will the new L5P will make? Here are our (hopefully-informed, yet totally unconfirmed) predictions.


First things first: the current 6.6L V-8 Duramax LML under the hoods of GM’s 2016 model year trucks is rated at 397 horsepower and 765 pound-feet of torque. Neither figure is insubstantial, as the engine was the most potent when it debuted back in 2011. Even more impressive is the fact that both figures are notably higher compared to the first generation of the Duramax, which was rated at 300 horsepower and 520 pound-feet of torque. However, as is nearly almost always the case in the automotive industry, the competition has not been sitting still: both Ford and FCA’s Ram have stepped up their HD truck game, and have done so big time.

Vehicle Horsepower (hp) Torque (lb-ft)
2016 GM Heavy Duty Trucks Duramax LML 397 765
2017 Ford F-Series Super Duty PowerStroke 440 925
2017 Ram HD Cummins Diesel 385 900

2017 Ford F-Series SuperDuty PowerStroke Diesel

Very recently, Ford has (famously) unleashed an all-new 6.7L V-8 PowerStroke Diesel. The motor is rated at a whopping 440 horsepower and 925 pound-feet of torque, besting GM’s 2016 LML Duramax by 43 horsepower and 160 pound-feet of torque.

What’s more, Ford might already be working on bumping the output of its new PowerStroke to 500 horses and 1,000 pound-feet.

2017 Ram Heavy Duty Cummins Diesel

Fiat Chrysler’s Ram also delivers some impressive numbers from its 6.7L Cummins High-Output Turbo Diesel V-8: 385 horsepower and 900 pound-feet of torque.

It’s not as powerful as Ford’s new PowerStroke, but it’s still topping GM’s 2016 Duramax by 135 pound-feet, while the Duramax is up 12 horsepower.

2017 GM L5P Duramx Turbo-Diesel V-8

Facing stiff competition from Ford and Ram, it seems pretty clear that GM needs its new Duramax L5P to do it big on both the spec sheet and in real-world performance. Interestingly, the 2016 Duramax LML is highly regarded when it comes to real-world performance, but today’s culture puts anyone not “on par” in the spec sheet department at a perceptional disadvantage.

This scenario is especially true based on current HD market conditions: GM can tout that its trucks have superior real-world towing performance until it’s blue in the face, but customers will continue making purchase decisions in favor of the Ford thanks to the F-Series having having the more impressive on-paper (on-display) specifications, not to mention perceptional variables.

All that is to say that the L5P needs to look good on paper, too. This is especially true considering that the consumer HD pickup truck segment has been racing to 1,000 pound-feet of (earth-shattering) torque for the last decade, with the heat intensifying year after year. The closer the 2017 Duramax L5P can get to that magical 1,000 lb.-ft. figure, the better — and it would be straight up awesome if GM could show up Ford and Ram by getting there first.

considered all that, our totally unconfirmed predictions for the new L5P in GM’s 2017 HD trucks are as follows:

  • 450 horsepower
  • 960 lb.-ft. torque

What do you think? Is that enough to not only compete with Ford and Ram, but to beat them — both on paper and in real-world towing and hauling performance?

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