Ford Super Duty: Heavy Capability with Heavy Power
Ford Motor Company has been building one of America’s favorite pickup trucks for 60 years. And it stands to reason the new Ford Super Duty is going to be a challenging lead to follow. For 2008, the Ford Super Duty truck lineup and the 6.4-liter Power Stroke diesel motor offer stump-pulling power and innovative improvements that may not be emulated by other light-truck manufacturers for some time to come. It comes down to one word: capability.
Within the Super Duty series that are relevant to members of The Enthusiast Network and Ford Truck World.com, we paid close attention to the Power Stroke Diesel powered F-250, F-350, and F-450 Super Duty pickups. Most of our readers either own or want to own a ¾-ton or 1-ton pickup if diesel power is a criterion. So we’ll stay focused on these two trucks. But the Ford F-450 is in a class by itself and shares all of the attributes discussed in this review.
In our full day of testing these vehicles at the Michigan Proving Grounds, we towed maximum trailer weights and in-bed payloads. It was raining all day, so wet weather traction and performance was real. Mud? There was enough deep mud, and mud-choked off-road trail ruts to make a water buffalo bellow, buck, and die. We four-wheeled these trucks (un-laden) through slick, narrow, and steep trail sections with suspension and tire setups available straight off the showroom floor.
Without question, Ford has been making ranch and work trucks long enough to know how to make a solid four-wheel drive vehicle, but one thing really stood out when it comes to four-wheelin’ with diesel power. It’s a flipping tractor. Regardless of the terrain or consistency of the soil, diesel-powered trucks, and in this case, Power Stroke diesel power, put out so much torque at low rpm’s that the tires just churn and pull the weight of the vehicle. With stone-stock tire tread design and tire-size, the F-250 Super Duty we tested confidently handled the muddy, rut-gouged, Michigan forest roads with steep inclines and sharp drop-off’s. In deep sand, even from a dead stop, the same high torque, low rpm, pulling power of the diesel motor kept the tires, and truck, moving forward. In running-board-deep mud, that same, tractor-like, pulling power stood head and shoulders above gasoline powered performance in similar terrain settings. That said, there is no drain-hole on the front differential housing for replacing the differential fluid. We were told there’s no need for one. Okay! But any person who trudges through the kind of terrain these trucks are capable of navigating might consider this an oversight.
So what makes the 2008 lineup of Ford Super Duty trucks stand out? Take the drive-train for example. Several years ago, when the Ford teams where planning for the 2008 Super Duty, they asked their loyal commercial fleet-buying customers for their feedback, good and bad, on what Ford could do to make a superior pickup truck. Well, from what we understand, Ford engineers got an ear full, and then some. Ford engineers decided to listen to their customer’s, and implement improvements from what they heard, not just from what they wanted to hear.
From the professional, large-fleet, Ford customers, the Ford design and engineering teams created unimaginable. They developed performance, durability, and reliability criteria and product evaluation tests that would torment every component of the new Super Duty trucks beyond a mere three or four expected product life-cycles. Components from motor mounts to bearing sizes, bolts, metal and other materials, were hydraulically drawn-and-quartered, along with counter parts from competing light-truck manufacturers, to develop the most rugged components possible. These tests would be scientifically simulated and statistically analyzed, but the mechanical methods were brutally medieval, yet effective. The Ford folks relentlessly tested their components, and their competitor’s components, to utter failure. Then they built something a little tougher…a little Ford Tougher.
POWER STROKE 6.4L
What resulted was a clean-slate redesign of the Power Stroke diesel motor, a change from the 6.0-liter to the new 6.4-liter motor (350 HP@ 3,000 rpm and 650 lb.-ft. torque @ 2,500 rpm), and more than 500 design improvements to the drive train as a unit. A big target mandate was meeting the new EPA emission regulations for environmentally cleaner operating diesel power, and that goal would be achieved along with many of the improvements, some of which we’ll visit in this session.
TWIN TURBOCHARGERS
Twin turbochargers! It’s more than cool, it makes sense. For the new 6.4-Liter Power Stroke V-8 diesel engines, the “Twins” are referred to as Series Sequential Turbocharger. A low-pressure turbocharger engages at low engine speeds and load. The first-stage (low-pressure) turbocharger gets the Ford Super-Duty rolling, then hands off the baton to the high-pressure turbo charger. The high-pressure turbocharger is controlled by the Turbocharger Actuator which controls the infinitely variable vanes inside the turbine housing, from open to closed positions. An example of when the high-pressure turbocharger vanes are closed is when the outside air temperature is cold. In cold conditions, the Turbocharger Actuator will close the turbine vanes; therefore engine exhaust back pressure builds up and creates more heat, thus warming up the engine quicker. However, from the seat-of-the-pants, you will simply feel smooth throttle response and power throughout the power range. There’s no waiting for the turbocharger to kick in. The “Twins” kick in from a dead stop right up through highway speeds; no lagging. The new turbo system can deliver up to 42 pounds of boost.
COMMON RAIL FUEL INJECTION
High-pressure common rail fuel injection system, housed inside the top of the cylinder head under the valve covers, is also new for 2008. Mounted between the cylinder banks, the high-pressure fuel injection pump pressurizes fuel to 26,000 psi, and then delivered to the combustion chambers through Piezo-electric injectors. Piezo-electric injectors fit into replaceable stainless steel injector sleeves that transfer heat from the injector to coolant passages in the cylinder head. New, four-valve, cylinder head and piston bowl design accommodates maximum cylinder pressures, up to five injections per combustion cycle further optimize throttle response, cold starting (down to minus 20-degrees F), and emissions control.
NO SMOKING!
Clean exhaust is another huge benefit you’ll enjoy with 2008 Super-Duty trucks. To meet new emissions standards, the Power Stroke exhaust system removes up to 97-percent of the particulates created by the diesel engine. Engine soot particulates (black smoke) are managed via the in the oxidation catalyst and diesel particulate filter, two components located in the exhaust system routing between the engine and the muffler. The diesel particulate filter (DPF) is self-cleaning. When the soot load builds up, a sensor activates a particulate burn-off, similar to a self-cleaning oven.
COOLING
By increasing the size of the radiator 33-percent, and using a larger water pump, coolant flow rate is enhanced from 75 gallons per minute to 140 gallons per minute. You’ll appreciate this fact as you tug your four-horse trailer over the Great Divide in Colorado next summer.
TRANSMISSION
When Ford engineers listened to their large commercial fleet buyer’s, one of the improvements that came out of the findings was to include how the transmission worked with the 6.4-liter Power Stroke in simulation testing. Testing the 2008 Power Stroke involved, for the first time, bolting the transmission to the engine during dynamometer testing. Ford engineers were able to study how transmission down-shifts and up-shifts affected the power train in simulated durability runs. One of the improvements that came out of this testing was a new transmission mounting system to reduce vibration and isolate the power train. Completely new gear sets were developed for the 2008, and three-plate, two-stage torque converter is now used.
TOW-HAUL
Getting the truck and payload moving is one thing. Slowing that pack of ponies down is another. If you are towing and running heavy loads in the truck bed, the Tow-haul gear selection in the Ford TorqShift five-speed automatic transmission is a marked benefit to safety and driver confidence. At the Michigan Proving Grounds outside Detroit, we hauled loaded trailers and loaded truck beds up and down as real-world road grades of the caliber likely to be found anywhere in North America. The tow-haul gearing changes shift points under acceleration, allowing the 6.4L Power Stroke to maintain higher rpm’s, stay up in the power range, and maintain gear selection as your rig crests the hill. On the downhill side, Ford’s TowCommand System works with the tow-haul transmission feature to downshift when the brakes are applied; allowing Ford’s true engine-compression braking system to slow truck and trailer, and maintain a steady speed downhill. In the actual “seat-of-the-Levi’s” experience, this capability was, perhaps, the most impressive benefit, along with the consistent power delivery of the dual turbochargers, position the 2008 Ford Super Duty truck as a class-leading work and fun truck.
 Electronically controlled telescopping trailer towing Powerscope mirrors are easy to adjust from the driver's seat, yet they fold back if you need the clearance. Here's one of the Michigan Proving Ground testing surface's, this one is designed to exponentially multiply the torment a Super Duty suspension and overall componentry will endure in several projected vehicle lifetimes. |  Deep sand puts a strain on any drivetrain. We tested from a dead stop, even speed, and tight turning. In each instance, the Power Stroke diesel and solid-axle four-wheel drive system kept the Super Duty trucks moving through the sandpit. |  We tested the Ford Super Duty F-250 and F-350's on the off-road test track at the Michigan Proving Grounds. The truck's were nimble. |
 Good ground clearance enables the Ford Super Duty pickups to handle most any off-road obstacle and retain safe on-highway stability. New for 2008, Super Duty is available with Rearview Camera System using the rearview mirror for image display. In addition to seeing what is behind the truck, the rear view camera makes lining up to a trailer hitch much more certain. Mounted in the tailgate handle, the camera activates when the vehicle is shifted to reverse. |  TowCommand System includes the TorqShift transmission with tow-haul mode and electronically controlled trailer towing mirrors. |  Full trailer loads and long decending hill grades were made for the new Ford Super Duty lineup of trucks. |
 Smooth, certain, power throughout the torque range can be attributed to the sequential turbochargers. |  Mud up to the doorsills, the low-end torque of the 6.4L Power Stroke Diesel and Ford's proven four-wheel drive system kept the tires churning through several passes in the pig poke. |  The Tow-Haul mode of the TorqueShift 5-speed automatic transmission changes shift points under acceleration, allowing the engine to maintain higher rpm's and stay in the power range. |
