How GM Squeezed 420 Lb-Ft of Torque From the GMC Sierra's Four-Cylinder

That's a 20 percent improvement over the 2021 truck.

2022 GMC Sierra AT4x
via GMC

The refreshed 2022 GMC Sierra has officially debuted, and while the big news revolves around the automaker's two new trims—the uber-premium Denali Ultimate and luxury off-roader AT4X—there's another hidden gem that GMC quietly stuffed into its press release: the base model and its four-cylinder engine.

Yes, really. Peer under the hood for a peek at the truck's turbocharged 2.7-liter four-cylinder engine that gained 72 pound-feet of torque overnight for a total of 420 lb-ft. That's a 20 percent improvement over the outgoing 2.7-liter turbo motor which makes only 348 lb-ft. Both motors still output the same amount of horsepower, leaving that number untouched at 310. Despite all of its new bells and whistles that have finally made the Sierra look like a truck designed in this decade, this was one of the things that stood out most to us. Here's how GM did it.

via GMC

The 2022 Sierra AT4X will receive GM's 6.2-liter V8 standard.

GMC says that achieved this increase thanks to some improvements made to the existing L3B engine. For starters, the automaker focused on strengthening some physical components. The cylinder block casting was revised to add additional rigidity, and the crankshaft was stiffened 30 percent which allowed for additional smoothness.

Those physical adjustments enabled GM's engineers to focus on squeezing even more power from the engine.

"Our team was able to find more toque in the flat part of our current torque curve between 1500 and 4000 RPM," a GM spokesperson told The Drive, "Calibration included increasing boost and of course injection and spark timing adjustments."

The one drawback that new buyers might actually feel is when that torque is delivered in the powerband. With the engine's new revisions, the peak torque rating of 420 lb-ft is achieved at 3,000 RPM—about halfway through the rev range—as compared to the old configuration which hit 348 lb-ft at 1,500 RPM. And while it is onset a bit later, the 72 ft-lb is no number to shake a stick at, so buyers will probably be a bit forgiving.

While this particular engine reworking has only been confirmed for the Sierra and Silverado, there's another vehicle with the L3B under the hood: the Cadillac CT4-V. The CT4-V currently makes 325 HP and 380 lb-ft of torque, though if the improvements made to the four-cylinder-equipped trucks happen to trickle down to the performance sedan, future owners could see quite the performance gain in the future. Sadly, GM tells us that it doesn't have anything to share about future products, but it is excited for its pickup customers to experience this torquey engine.

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