Cummins X10 earns early praise in demanding on-road testing

With impressive power, strong fuel economy and high marks from drivers, Cummins’ new X10 diesel is earning early praise in some of trucking’s toughest applications.

Scheduled to launch in 2027, the 10-liter heavy-duty engine builds on the proven lineage of the company’s L9 and X12 engines while delivering greater power density, efficiency and versatility.

Thousands of hours and more than 2.5 million miles of on-road testing across challenging climates and terrain are putting those capabilities to the test.

“I was very impressed with it,” said Jeff George, production specialist at Altec Industries in St. Joseph, Missouri. “It’s got quite a bit of throttle response. When we went up the 25-degree grade, it had no issues and walked that hill like it was nothing. I think it’s going to be a gamechanger for us.”

The X10 also earned praise from Austin Hill, technical sales representative at Stoops Freightliner-Quality Trailer in Fort Wayne, Indiana.

“It feels good. It shifts right. I was really impressed on the hill,” Hill said. “About three-quarters of the way up, I got on it and it pulled right through. I’m really excited about it.”

Hill and George both drove a Freightliner 114SD equipped with the Cummins X10 and an Allison 4K transmission. With 450 horsepower and 1,650 lb.-ft. of torque, the flatbed truck handled a gross vehicle weight of 55,000 pounds.

Cummins Product Manager Tara Johnson said the X10’s versatility has been a key focus during nearly four years of extensive research and development across North America.

“We’ve tested the X10 across North America in a wide range of vocations, climates and terrain — from transit and regional haul to refuse, pickup and delivery, and mixers,” Johnson said. “That breadth of testing gives us confidence in the X10’s ability to perform across the diverse applications our customers operate every day.”

With the X10 positioned to succeed both the L9 and X12 in many applications, the engine has been developed to meet a broad range of fleet and driver expectations.

“The feedback we’re receiving from customers reinforces our confidence that the X10 is ready to meet the broad range of needs served today by the L9 and X12,” Johnson said. “Our focus has been on making that transition while delivering the performance and capability customers expect.”

Driver feedback has been another important part of the X10’s development, particularly in applications where performance, responsiveness and comfort can influence the overall experience behind the wheel.

“Positive driver feedback is important because the driver experience can have a meaningful impact on how a vehicle is operated and ultimately on a fleet’s overall experience with the product,” Johnson said. “When drivers tell us they appreciate the X10’s performance, responsiveness and refinement, that adds another important dimension to the value we’re working to deliver for fleets.”

Building on success

While the X10 is new to Cummins’ engine lineup, its development draws on decades of experience with engines such as the L9 and X12. Proven components and systems were retained where they made sense and evolved where opportunities existed to improve performance, efficiency and serviceability.

“The X10 builds on technologies and components with a proven track record in our existing products,” Johnson said. “Our approach was to retain what was working well while improving the areas where we could deliver additional efficiency, performance and value for customers.”

The same Cummins engineering organization behind the L9 and X12 took on the challenge of developing an engine capable of serving applications historically covered by both platforms. The result combines increased power density with improved fuel economy and the technologies needed to meet 2027 emissions requirements.

“The X10 builds on aftertreatment and EGR technologies that Cummins has developed and refined over many years,” Johnson said. “The architecture has evolved significantly, but the underlying technologies are well understood. We’ve continued to improve those systems to deliver the efficiency, performance and reliability customers expect from Cummins.”

Those improvements extend to fuel economy and maintenance. The X10 offers up to a 4% fuel economy improvement over the L9 and up to a 2% improvement over the X12. Oil drain intervals also increase from up to 50,000 miles with the L9 to as much as 75,000 miles with the X10, depending on duty cycle. Cartridge-style lube and fuel filters are designed to further reduce maintenance requirements and operating costs.

“Customers will be able to expect, from an L9 perspective, increased power and torque, extended maintenance intervals as well as fuel economy, and from an X12 perspective, you’ll get better fuel efficiency in a lighter package,” said Lyndon Jones, Cummins vice president of North American Sales and Customer Support.

As the X10 prepares to take on applications long served by the L9 and X12, X10 Program Leader RaNae Isaak said its impact will ultimately be measured by the work customers depend on these engines to perform every day.

“If you’re serving in a market about transit, it’s about people. It’s about reliability. It’s dump trucks that are hauling gravel. It’s cement trucks that are pouring concrete for your new home. You’ve got emergency vehicles,” Isaak said. “And if you look at many of those applications, you see an L9 or you see an X12. That’s where an X10 will be.”

With its 2027 launch approaching, millions of test miles and early customer feedback are providing a clearer picture of what the X10 can deliver. Soon, the engine will move from proving itself in testing to taking on the everyday work long handled by the L9 and X12.