Ford’s second-generation 6.7-liter Power Stroke V8 turbo diesel now boasts 440 horsepower, up from 400 horsepower, and 860 lb.-ft. of torque, up from 800 lb.-ft., across all Super Duty models from F-250 to F-450.

The 2015 F-450 tops the F-Series Super Duty pickup truck lineup with maximum fifth-wheel/gooseneck towing capacity increasing to a class-leading 31,200 pounds, a gain of 6,500 pounds. The truck’s gross combined weight rating increases to a class-leading 40,000 pounds, a gain of 7,000 pounds.

F-350 increases maximum fifth-wheel/gooseneck towing capacity as well, to 26,700 pounds, from 23,200 pounds, and the gross combined weight rating goes up 4,500 pounds, to 35,000 pounds.

The improved ratings are a result of designing and engineering the truck as an integrated system. This approach has enabled Ford engineers to optimize performance across the full Super Duty lineup.

“Our chassis people work with our powertrain people to develop more than a great truck,” said Doug Scott, Ford Truck Group marketing manager. “This is a machine engineered for work.

“We’re the only manufacturer that develops and builds our own powertrains in this class,” Scott added. “When you combine that with a chassis that’s purpose-built for best-in-class power and torque, you can feel it in the way the new truck drives, especially when towing big loads.”

Power Stroke engine improvements
The 2015 Super Duty achieves best-in-class towing performance with a second-generation 6.7-liter Power Stroke V8 turbo diesel engine that has been further developed to provide more power, torque and efficiency.

“The 6.7-liter Power Stroke V8 turbo diesel was already a stout engine,” said Robert Fascetti, Ford vice president, Powertrain Engineering. “The improvements we’ve made essentially give Super Duty customers an engine that is also designed for our larger F-650 and F-750 medium-duty trucks. They may not realize how tough this engine really is.”

Key innovations on the 6.7-liter Power Stroke are its compacted graphite iron engine block and reverse-flow layout. This segment-exclusive design places the exhaust inside the engine’s V-shape with the air intake positioned on the outside, resulting in a variety of advancements:

• Shorter airflow from the exhaust system to the new, larger turbocharger sitting between the engine’s cylinder banks improves turbo responsiveness – key to providing torque quickly to truck customers when they need it most
• Positioning the turbo inside the engine’s valley helps isolate the engine’s hottest temperatures, improving performance and efficiency while also reducing noise, vibration and harshness to enhance driver comfort

Other upgrades include a larger turbocharger for increased airflow, resulting in more power. The compacted graphite iron engine block is stronger yet lighter than cast iron, is more wear-resistant, and has enhanced sealing properties.

“The designers of the original 6.7-liter Power Stroke V8 turbo diesel predicted it would eventually need to be upgraded for higher output,” said David Ives, Ford Power Stroke technical specialist. “They made it easier to add a larger turbocharger, increasing airflow and creating more power for dramatically improved performance, and yet we haven’t lost any efficiency.”

A further benefit of the larger turbo is improved engine braking, manually controlled by a push-button switch on the dashboard. Extra braking power helps reduce wear and tear on wheel brakes and requires less manual brake application from the driver, especially on downhill grades.

New injector tips spray a higher flow of atomized fuel into the cylinders, which helps provide additional power, a more complete burn and reduced noise, vibration and harshness. Other benefits include lower emissions and less fuel deposit buildup on the intake valves over time.

Chassis improvements
F-350 Super Duty is available with a high-capacity towing package that includes new front springs and a wide track axle, increasing the gross combined weight rating with the 6.7-liter Power Stroke engine from 31,900 pounds to 35,000 pounds.

Improvements to F-450 that allow it to handle the increased tow rating include commercial- grade 19.5-inch wheels and tires, upgraded rear U-joints and suspension components with new leaf springs, front and rear stabilizer bars and shocks. The steering system has stronger gears and linkages and the fifth-wheel/gooseneck has increased towing capacity. The brakes, shared with Super Duty chassis cab models, are larger and feature new antilock calibration for enhanced performance.