Powertrain manufacturer Detroit, part of Daimler Truck North America, this week revealed its Gen 6 lineup of heavy-duty truck engines designed to comply with EPA 2027 standards, including the new low-Nox rule. Company leaders say the upgraded DD13, DD15, and DD16 engines for Freightliner and Western Star trucks deliver efficiency and reliability gains in a familiar package, while also boosting performance in multiple applications, including bulk transportation.
In the tank truck sector, where revenue is linked to every pound of payload, engine displacement and weight-to-power ratios are the primary metrics for competitiveness. And, historically, reaching the 500-horsepower threshold required jumping to a 15-liter displacement engine, which incurred a significant weight penalty. But Detroit’s new DD13 rating—505 hp and 1,750 lb.-ft. of torque—fills the gap, providing heavy-haul power in 13-liter footprint, DTNA reported.
For more on the compliance and efficiency gains in Detroit’s Gen 6 engines, see the coverage from our FleetOwner affiliate. And for more on the technical and maintenance aspects, read this report from Fleet Maintenance.
“If it is a weight sensitive application, they’re probably already using the DD13,” Steve Collins, DTNA director of field sales engineering, told Bulk Transporter during a Feb. 17 media briefing. “And so adding in that 500-hp rating is a nice sweet spot for them. They’ve got additional power and torque without having to jump up into a higher displacement engine.”
Detroit’s enhanced engine platform also features newly optimized asymmetric turbocharger technology with a ball-bearing design that spools faster, enabling on-demand delivery of increased airflow. And a new wastegate design provides consistent performance across a wider range of operational parameters, especially at higher altitudes, DTNA said.
“When you’re maxed out at gross load or in heavy-haul applications and pulling up the hill, effective throttle response, and the turbo being able to keep up with that demand, is important,” Collins said. “So, there will be drivers in those applications who notice those improvements.”
Aggressive downspeed power
Additionally, the Gen 6 DD15 boasts two new power ratings—425 hp and 455 hp at 1,900 lb.-ft. of torque—that improve total cost of ownership for bulk haulers, DTNA indicated. The new ratings are designed to facilitate aggressive downspeeding, allowing fleets to operate the engine at lower RPMs to maximize fuel economy. And by delivering 1,900 lb.-ft. of torque, the Gen 6 DD15 enables the use of “super-fast” rear axle ratios, such as 2.05, meaning the engine can work harder at lower speeds without sacrificing the gradeability tank truckers require.
“That’s the most torque we’ve ever produced out of the DD15,” Collins said.
The DD13 and DD15 engines will be available beginning in January 2027. Gen 6 DD16 production will follow in January 2028, DTNA noted.
“This is exciting for us,” said David Carson, DTNA senior vice president of sales and marketing. “We love to launch trucks, but launching an engine is even more special. It’s the heartbeat of the truck, and it’s super important for customers in terms of innovation, efficiency, and reliability.
“With our customers in the current freight market, they’re being very discerning. They want a return on their investment, and we’re fully prepared with our engine launch for 2027 and the emission requirements. But this is not just a launch for an emissions change. We are bringing additional value and innovation to this engine. We’ve been involved in the engine business here in North America—in this particular location [Redford, Michigan]—for nearly 90 years.
“We’ve been producing the best diesel engines in the commercial vehicle space, and we intend to maintain that position in 2027 and beyond.”
About the Author
Jason McDaniel
Jason McDaniel, based in the Houston TX area, has more than 20 years of experience as an award-winning journalist. He spent 15 writing and editing for daily newspapers, including the Houston Chronicle, and began covering the commercial vehicle industry in 2018. He was named editor of Bulk Transporter and Refrigerated Transporter magazines in July 2020.