Zac Quinn 
General Motors recently updated the 3.0L Duramax turbo-diesel I6 engine to give it more power and efficiency. With revised pistons, raised compression, and increased power to 305 horsepower and 495 lb-ft of torque, it’s a heavily upgraded powerhouse. Placed within a 2023 GMC Sierra 1500 Denali, our friends at TFL have put the engine and the truck on the world’s toughest towing test—the Ike Gauntlet.
GMC 1500 Sierra With LZ0 Duramax: Ike Gauntlet
The Ike Gauntlet is the world’s toughest towing test due to its placement on a stretch of the I-70 Interstate that goes up to the top of the Colorado Rocky Mountains at 11,158 feet above sea level. It’s an 8-mile stretch of the grueling highway with a maximum of 7% grade. If that wasn’t harsh enough, remember that altitude results in power losses for an engine. As with humans, the higher you are, the harder it is to breathe, thus why you can find Boost Oxygen cans in almost every corner of Colorado; sadly, engines don’t get such treatment.
The new LZ0 version of the 3.0L Duramax turbo-diesel is found within the GMC Sierra 1500 Denali Ultimate for this test, the new top-of-the-line trim for GMC trucks. In addition, a Roamer1 off-grid and off-road luxurious camping trailer are loaded up to a total weight of 7,000 lbs, which significantly compares to other vehicles that have towed the camper up the Gauntlet.
Based on the results found in the video below, the new 3.0L Duramax turbo-diesel I6 is one of the most efficient trucks to take on the test. It showed 6.9-6.0 MPG during the climb, though its acceleration speed and downhill grade-shifting weren’t mind-blowing. The Sierra 1500 registered a suitable four brake applications on the way down, which is better than average but not the greatest. The truck also showed an 8-minute and 13-second climb. In simpler terms, the new turbo-diesel is ultra quiet, refined, and efficient, making it a great engine to keep on your list if you’re planning to tow a trailer over long distances.
