GM Has Apparently Canceled its Rumored Turbo Straight-Six Truck Engine

2022 Chevy Suburban Diesel Image: Chevrolet

The auto industry’s transition to electric vehicles hasn’t exactly stopped gasoline engine development. Even though the future may be electric, gas engines will still be around for a long time, and automakers are still trying to develop new, more efficient internal-combustion powerplants Apparently, at least one of those has gotten the axe: GM Authority reports that General Motors has canceled development of an all-new turbocharged straight-six engine that’s been rumored for some time.

Last year, it was reported that this new straight-six engine was in the planning stages. It was suggested that it would be built from the 2.7-liter turbocharged inline-four currently used in certain trims of the full-size Chevy Silverado / GMC Sierra as well as the all-new Chevy Colorado and upcoming next-gen GMC Canyon. That engine makes 237 hp in basic tune, or 310 hp in high-output trim in the Colorado.

This straight-six apparently would have made those numbers pale in comparison. Sources say that GM was shooting for 500 hp and 500 lb-ft of torque. Those numbers would have outgunned both of GM’s small-block V8 truck engines, the 5.3-liter and the 6.2-liter. As the rumor goes, the straight-six would have seen duty in GM’s full-size pickups as well as their SUV variants, namely the Tahoe, Suburban, Yukon and Escalade.

When reached by Jalopnik, a GM representative would not confirm that the turbo straight-six had ever been under development, and would not comment on the rumor that it had been canceled.

If the rumored engine has truly been axed for good, GM may come to regret that decision. Competing trucks and SUVs from Ford, Stellantis and Toyota have all added turbocharged six-cylinder options lately. The Toyota Sequoia currently offers a twin-turbo hybrid V6; Ford has been using Ecoboost V6s in the F-150, Expedition and Navigator for years; and Stellantis offers the Jeep Wagoneer with a new 3.0-liter 510-hp twin-turbo straight six.

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Buyers wanting something new or different in their GM body-on-frame models may now have to wait until the General unveils its next generation of small block V8s, or go with the company’s 3.0-liter Duramax turbodiesel. In a way, it’s a shame — with those rumored specs, GM’s straight-six engine could have easily been competitive with the best boosted sixes on the market today.