(6.4L V8 Twin-turbo Diesel 6-speed Manual 8.2 ft. Bed)
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Dominating the heavy-duty towing market
Dan Edmunds, Director of Vehicle Testing
When it comes to sales, Ford's F-Series truck has been the dominant force in the U.S. truck market for quite some time. And if you want to know why, the new 2008 Ford F-450 Super Duty pickup stands as a prime example.
Sure, most people will never need a truck with the sheer brute strength of the 2008 Ford F-450 Super Duty pickup with its 6.4-liter PowerStroke diesel and 24,500-pound towing capacity. But that's not the point. The point is that some people -- especially snowbirds with huge fifth-wheel trailers -- have shown a need for the ultimate towing machine.
Making their own bed
In the past, if you wanted an F-450 dually that didn't look like an industrial appliance, you had to convert a commercial-grade F-450 cab-chassis, the unfinished one that comes with naked frame rails behind the cab. Several companies make a tidy living from grafting standard F-350 8-foot beds (or even fiberglass replicas) onto the back of cab-chassis combinations. Unfortunately there are major problems involved.
First, a commercial chassis usually features a narrow standard frame with straight rails just 34 inches apart. A conventional civilian pickup actually employs wider-spaced frame rails because it doesn't have to be compatible with moving-van cargo boxes, tow-truck setups and other industrial gear. Bolting a typical pickup bed to a narrow cab-chassis frame requires hand labor and fabrication.
And then there is the wheelbase issue. An F-450 crew-cab cab-chassis measures 176.2 inches, while the equivalent F-350 spans only 172.4 inches. When an 8-foot box is adapted to the commercial chassis, there's a 4-inch gap behind the cab that has to be bridged with an obvious filler panel.
Ford solves both problems at once by making the F-450 Super Duty pickup in-house. For the back half of the frame, F-350-dimensioned rails bring the frame-spacing, bed mounts and wheelbase along with them. An 8-foot pickup box drops straight on, and the unsightly cab-gap is history.
Load handling redefined
Up front, the F-450 is all commercial grade. The 4x2 and 4x4 alike employ a radius-arm suspension setup to locate what Ford calls a "wide-frame monobeam," a very wide solid axle with coil springs. This design not only affords massive load-carrying capacity but also 45 degrees of steering lock.
As a result, the F-450 pickup has a tighter turning radius than comparable F-350 and -250 designs, some 51.5 feet versus 56.5 feet. During a side-by-side parking lot comparison between the two, the benefit is immediately apparent.
As expected, the components underpinning it all are mighty rugged. The F-450's commercial-grade 225/70R19.5F Continental tires are unsympathetically stiff and need to be run in the neighborhood of 80 psi. In order to regain the lost ride comfort, the progressive, multistage rear-leaf springs are 8 inches longer and have been carefully tuned to combine a reasonably comfortable ride with good load-carrying capacity.
It all adds up. The F-450 pickup, sold only with dual rear wheels, can pull up to 24,500 pounds with a gooseneck or fifth-wheel hitch, or 16,000 pounds with a conventional setup. An equivalent F-350 (a leader in towing capacity in its own class) manages 18,800 pounds and 15,000 pounds, respectively. Meanwhile, the F-450 shares the F-350's 6,000-pound payload.
After driving an F-450 pickup with and without a trailer, we're sure that while the unladen ride is better than it might otherwise be with a true commercial cab-chassis, it's still not ideally suited to daily driving. Considering the F-450's towing capability, this is totally understandable.
A magical transformation results when a 20,000-pound fifth-wheel trailer is clamped on, as was the case during our test-drive in Nevada. Not only does the truck's laden horizon remain parallel to the real one, the ride smoothes out and body motions are quite subdued.
Diff'rent power strokes
Motivating so much truck and so much payload takes some serious grunt. To that end, Ford has thoroughly reworked the PowerStroke V8 diesel. In fact, the camshaft is the only carryover part from the previous version.
A larger bore results in a displacement increase from 6.0 to 6.4 liters, and a forged crankshaft now spins in larger bearing journals and is connected to sturdier connecting rods. Four-valve cylinder heads sandwich multilayer steel head gaskets.
For this new V8, Ford employs common-rail direct injection and Piezo-electric injectors. Because the fuel is administered in up to five metered spurts per combustion cycle rather than all at once, reliability is improved, air emissions are reduced and the engine even runs quieter.
Twin-sequential turbochargers deliver 42 psi of boost. At low rpm, the smaller variable-geometry turbo spins up quickly to help with getaways from a stop. In the midrange of the V8's power band, a larger fixed-geometry unit joins in, eventually taking over at the top end of the power band. The exhaust exits through a flow-tuned particulate filter that screens out almost 97 percent of the diesel particulate emissions.
As a result, the 6.4-liter V8 delivers 350 horsepower at 3,000 rpm and a massive 650 pound-feet of torque at 2,000 rpm. While this is an impressive improvement over the 6.0-liter V8's 325 hp and 570 lb-ft, it merely levels the playing field. Chevy's 6.6-liter Duramax diesel V8 makes 360 ponies and 650 lb-ft of torque. And it's mated to a six-speed automatic, while the Ford's F-450 still has a five-speed automatic.
After we drove the F-450 for several runs up a sinuous 5-to-6-percent grade climbing out of Laughlin, Nevada, it was clear that the 20,000-pound load we were dragging wasn't leaving our mount breathless. Unencumbered, Ford claims a 1.0-second improvement in zero-to-60-mph time for the F-450 over last year's PowerStroke F-350. Based on our 2006 Heavy-Duty Truck Comparison Test, this performance suggests the F-450 will get to 60 mph in about 8.5 seconds, much like our Silverado 3500 Duramax.
But there's more to towing 24,500 pounds than horsepower and torque. Commercial suspension aside, the F-450 pickup trumps the Chevy by employing 4.88:1 final-drive ratio.
A large-capacity cooling system keeps the big diesel happy in its work. There are no fewer than six heat exchangers and a radiator that's 33 percent larger than last year. To ensure good airflow to the radiator, a new nose for the bodywork accommodates a grille with lots of openings, while the front bumper has been repositioned to ensure it doesn't obstruct airflow.
More options to choose from
The F-450 is not only massive on the outside but also massive (in design spirit, anyway) on the inside. A brand-new interior features a dash that carries lots of heavy-duty design themes, although it looks a bit overstated. On the plus side, the controls on the center stack are familiar and work well. And there are useful storage compartments everywhere.
For the first time, the new F-450 pickup cabin can be appointed with the full array of regular F-Series Super Duty options. It wasn't previously possible to get a cab-chassis conversion with factory-installed goodies like rear-seat entertainment, an auxiliary audio input jack and, of course, the King Ranch trim package. Now your ultracapable tow rig can be well-appointed, too.
If you don't need the towing capacity of the F-450 chassis, the F-250 and F-350 benefit from the same revamped interior and exterior styling, and both can be equipped with the new 6.4-liter PowerStroke diesel engine.
But if you're considering retirement in a three-axle fifth-wheel travel trailer with dual-sliders and granite counter tops, and want a leather-lined tow implement with all the trimmings to yank it about, the new 2008 Ford F-450 Super Duty pickup is the one to look at hard.
With 24,500 pounds of towing capacity, the 2008 Ford F-450 might well be the only factory-built, heavy-duty choice that you have.
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