Mack reveals next-gen 13-L engine platform for EPA 2027

Mack Trucks' next-generation MP13 engine is a 13-liter redesign that fully meets EPA 2027 requirements while offering gains in efficiency, responsiveness, and overall performance.

“Mack trucks will have a fully compliant engine for EPA 2027 regs,” Govi Kannan, Mack Trucks’ SVP of global products, told media at the Advanced Clean Transportation Expo in Las Vegas. “This is going to be our strongest and most powerful 13-liter that we have built, at 540 horsepower and 1950 lb.-ft. of torque.”

One big change with the next MP13 diesel engine block is that it will be composed of a new compacted graphite iron to increase strength and reduce weight. While the block itself is lighter than its predecessor, overall weight of the engine will likely still increase slightly, not due to the new material but the addition of new components.

“The graphite iron brings durability, but it’s also lighter than the prior block,” Fernando Couceiro, VP of highway trucks for Mack, added. “Because you’re adding other components, [the block's] kind of offsetting a little bit of the weight increase.”

Performance and efficiency gains come from a few combustion and hardware upgrades, according to Kevin West, senior product manager for vehicle propulsion at Mack.

“With the new MP13, we have a higher compression ratio,” West said. “We go to a 20:1 compression ratio now and have a new turbocharger that improves efficiency and responsiveness.”

A high-pressure fuel pump increases cylinder pressure, while a redesigned turbocharger with ball-bearing wastegate and optimized vane geometry will improve airflow, efficiency, and throttle response.

Fuel atomization has also been improved through a seven-wave piston bowl design for a faster, more complete burn, helping reduce soot and particulate.

Like with Volvo’s new D13, engine braking sees a significant increase as well, rising more than 20% to up to 630 braking horsepower using a pre-turbine throttle, compared to the previous 505-hp rating.

“When you’re in a loaded dump truck going down a 30 percent grade and it just walks you down, it's impressive,” West continued. “I believe it is one of the best engine brakes we’ve ever had.”

The redesign is based on the same core platform that powers Volvo’s trucks, but Mack has tweaked the torque and horsepower curves to better meet customer needs.

How MP13 improved fuel efficiency, emissions

There are also fuel economy improvements. In the Mack Granite, the new engine delivers up to a 3% gain in fuel efficiency, driven by the new piston design and enhanced downspeeding. Mack also attributes these gains to the cleaner and more compliant combustion supported by updated aftertreatment systems.

“We have introduced the wave pistons,” Kannan said. “With extra pressure, we are going to get a cleaner burn, and hence the fuel economy when it comes to the engine.”

Peak torque is now available as low as 900 RPM, improving drivability and supporting downspeeding. To complement the engine changes, Mack has also updated its automated manual transmission to deliver quicker, smoother shifts, according to the OEM.

When it comes to emissions, Mack reports a reduction of almost 75% in NOx, achieved through a combination of in-cylinder improvements and aftertreatment enhancements. A heating system was also added to support catalytic efficiency under low-temperature operating conditions.

The next MP13 will also be compatible with R100 renewable diesel and biodiesel blends up to B20, up from the previous MP13’s B10.

When and where will the new engine be available?

The engine will be available for order starting August 2026, with production timed to model year 2028 vehicles. It will be offered in the Mack Pioneer, Anthem, Keystone, and Granite.

Mack’s LR + TerraPro will use the new X10 by Cummins in place of the MP7. The company is discontinuing the 11-liter MP7 but will continue offering natural gas and electric powertrains across select models.