WEST PALM BEACH, Fla. — Volvo Trucks has added a 455-hp rating to its XE13 powertrain package, which through a concept dubbed downspeeding, allows the engine to run slower, thus saving fuel.

The XE13 (exceptional efficiency) package was introduced last September and at that time was only available in a 425-hp rating. The new rating provides some extra pulling power while still allowing the engine to cruise at a low 1,150 rpm at 65 mph, Volvo officials announced.

“At cruise, it will drive exactly the same as the 425-hp rating,” said Ed Saxman, Volvo Trucks product manager, powertrain. “For those who want a little more power – maybe they operate in the Rockies with long pulls and steep grades – they’ll have 30 more horsepower.”

Volvo officials said the XE13 package allows the truck to operate in a lower rpm range at a given vehicle speed, typically turning 200 rpm slower. Customer data has indicated trucks with the XE13 package consistently operate in the engine’s sweet spot of 1,050 to 1,500 rpm, with up to 70% of their operation in the most efficient range of 1,100-1,200 rpm.

“Operating in this range yields about a 1.5% fuel efficiency improvement for every 100 rpm of downspeeding, so the XE13 package with the 455 hp rating will deliver about a 3% fuel efficiency gain,” Saxman said.

Integral to the XE13 is Volvo’s I-Shift automated transmission and a set of specifications including: a D13 engine with 455 hp and 1,750 lb-ft of torque; the I-Shift with a 0.78:1 ratio; axle ratios of 2.64-2.69; and the proprietary software that makes it all work.

“It does require a limited array of options,” Saxman acknowledged. “You get one size, but it works well.”

Saxman said the first trucks spec’d by customers with the XE13 powertrain package are now in production.

“Orders are just now starting down the line,” he said. “We’re excited with the results we’ve got, which are evenly split between customer orders and dealer stock. Things look really good.”

Volvo expects its new powertrain package will have a broader appeal with the additional horsepower availability.

“Our first introduction of the XE13 concept focused on exceptionally fuel-conscious fleets that spend considerable time cruising at highway speeds,” said Ron Huibers, Volvo’s president of North American sales and marketing. “The new 455 hp rating is aimed toward the higher performance demands of long-haul fleets.”

Truck News took a drive in a Volvo VN with the XE13 package last fall. You can read that report here.