New 4.9L SIDI V-8 and two-mode hybrid system
For the first time, GM’s rear-wheel-drive two-mode hybrid transmission is paired with a smaller-displacement version of the small-block engine. The new V-8 4.9L E85-capable engine powers the Denali XT with an estimated 326 horsepower (243 kW). It uses direct-injection technology to produce the power of a larger engine, but consumes less fuel and produces lower emissions.
Also, the functionality of GM’s Active Fuel Management system has been expanded through the use of hybrid technologies, enhancing the cylinder-deactivating feature to further improve fuel efficiency.
The Denali XT’s two-mode hybrid system is partnered with the 4.9L engine and uses an electrically variable transmission to enhance fuel efficiency in city and highway driving. In city driving, all-electric propulsion is used at low speeds; on the highway, fixed-gear operation enables efficient performance even when towing a trailer.

The specific characteristics of the Denali XT allowed the synergistic evolution of GM’s small-block V-8 and two-mode hybrid beyond the recently introduced in GM two-mode hybrid products, such as the GMC Yukon Hybrid and Sierra Hybrid. During this optimization process, additional powertrain technologies have been integrated, including Active Thermal Management, which transfers thermal energy from one driveline component to another to improve efficiency; and a high-efficiency axle configuration, which fundamentally reduces the losses normally associated with conventional axle configurations.
The integration of the advanced internal combustion engine technologies and two-mode hybrid system on the Denali XT reinforces GMC’s Professional Grade position as a brand that continues to exceed customer expectations.
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