2008 Ford F-Series Super Duty Review

When the engineers at Ford sat down to design the 2008 F-Series Super Duty, you can bet that beads of perspiration formed on their foreheads relatively quick. Maybe it was as if they could feel the unrelenting steely gaze of hundreds of thousands of workin' folk peering over their shoulders as they began the redesign of the quintessential workin' man's pickup truck. The pressure must've been immense to make relevant, functional changes without compromising the integrity of the Super Duty name.

Well, their work is done, and we recently had the opportunity to drive the entire new F-Series Super Duty family of trucks in the Texas hill country. Here's what's new with the four-wheel-drive models.

Enio Gomes, Manager of the North American Diesel Power Stroke Program, notes that the only major parts shared between the previous 6.0L Power Stroke and the new 6.4L Power Stroke are the oil pan and camshaft. We also heard that Ford was far more hands-on with engine supplier Navistar International during the development of the new engine than they were in the development of the previous 6.0L engine. The new 6.4L Power Stroke V-8 is optional ($6,895) on the F-250 and F-350 and standard on the F-450. Ford says it's the most powerful Ford pickup diesel engine ever. It generates 350 hp at 3,000 rpm and a whopping 650 lb-ft of torque at only 2,000 rpm. It's important to note that thanks in part to new high-pressure common-rail fuel injection with micro-precision piezo-electric injectors, 100 percent of its torque is generated at that low 2,000 rpm figure. The engine features a cast-iron block, heads, and bedplate (the one-piece bedplate locks down the crankshaft) that are proven to stand up to the combustion forces of a hard-working diesel engine. This cast-iron construction also helps dampen noise and vibration, adding to the 6.4L's refinement. Further, the new engine features a bigger crankshaft, powder-forged connecting rods with stress-fractured bearing journals, oil-jet piston cooling, a larger radiator, a greater flow-rate water pump (doubles the flow rate from the previous engine), and a high-capacity oil pump.

One of the 6.4L's most fascinating features is the new dual sequential turbos. These two turbos work in tandem. The small, electronic-controlled, smart remote variable-geometry turbocharger comes on at low rpm to provide extra boost at take-off. As rpm increase, the larger fixed low-pressure turbo joins the smaller turbo to boost power through the middle of the torque curve. As speed is increased, the larger turbo takes over. The result is virtually no turbo lag and smooth power throughout the rpm band. Ford says this system is one of the reasons why the 6.4L engine's zero-to-60 times are more than a second faster than the 6.0L's.

The driving force behind the development of the new 6.4L engine was ever-tightening emissions regulations. To meet these stringent new regs, the engine was designed with a number of high-tech tweaks including the aforementioned high-pressure common-rail fuel-injection system (26,000 psi helps make a cleaner burn, thus reducing emissions) as well as a new exhaust-gas recirculation system (pumps burned gases through two 440mm coolers, which, combined with other steps, help limit the formation of nitrogen oxides) and a one-piece self-cleaning, self-diagnostic diesel oxidation catalyst and diesel particulate filter that removes nearly 97 percent of the diesel particulate.

When it comes to gearboxes, a toughened-up TorqShift five-speed automatic transmission is standard. The two-speed transfer case is available with either manual or electronic shift.

The F-250 and F-350 continue to use the '05-introduced Dana 60 axle up front, and it still features 35-spline outers and Warn-supplied hubs. The front sway bar is now mounted differently due to the fact that the front of the Super Duty frame has been lowered 7 inches. In the rear is the familiar Ford 10.5-inch axle, but it has been fitted with a new finned aluminum diff cover to help dissipate heat. The dual rear-wheel F-350 gets a Dana 80 rear axle. The rear leaf springs on these models have been lengthened 8.25 inches from the center of the axle forward to improve ride quality. These models also have new shock tuning designed to improve ride and braking performance. The steering box is still supplied by Visteon, but the internals have been modified to provide finer control and smoothness in steering. The new F-450 Crew Cab dual rear-wheel pickup rides on a frame specific to this model and it's different than the frame under the F-450 cab/chassis model. Up front, the F-450 pickup has a Dana Super 60 axle, and in the rear it rolls on a beefy Dana 110 axle. The F-450 also has different spring packs with thicker leaves. These things combine to produce a rig that can carry up to a whopping 5,720 pounds of cargo or tow up to a 19,000-pound 5th-wheel trailer.

The front of the new Super Duty looks vastly bigger than the outgoing model because it is. The hood height is 4 inches taller and the bumper has been lowered. Adding to the tall look are the headlamps, which have been lowered by 3 inches and stacked under the turn signals. Pat Schiavone, Design Director of Trucks, SUVs, and CUVs, explained that the headlamps were lowered so that they didn't shine directly into the rear window of passenger cars. The front bumper was lowered to keep it more in line with the bumpers on passenger cars. The large grille ensures good airflow to the radiator, and the new front step bumper has a semi-truck look. Speaking of the grille, it is now mounted to the hood instead of the frame. While this may seem inconsequential, it actually is a big thing because it allows for a tight, consistent tolerance gap between the hood and the grille instead of the 12mm gap and visible seal found on the previous-generation Super Duty. Other optional new exterior enhancements worth noting: a stowable bed extender, PowerScope trailer tow mirrors, and a unique tailgate step.