Full Test: 2008 Ford F-450 Super Duty

Don't buy the 2008 Ford F-450 Super Duty because it looks like a badass truck. If all you need to tow is your ego, then a light-duty pickup is for you. Instead, this F-450 Super Duty with its PowerStroke 6.4-liter V8 turbodiesel is meant to be hitched up to a trailer.

For those hauling heavy loads — whether it's an extended horse trailer, a part-time home for recreation in remote areas or even a pair of hobby cars — your steed has arrived. The 2008 F-450 Super Duty is the best thing to happen to towing since the fifth-wheel trailer.

We tested an F-450 Super Duty 4x4 Lariat as a dually crew cab setup with a PowerStroke 6.4-liter V8 turbodiesel under the hood, and we hooked it up to a trailer as soon as we could. Anything less is for weenies.

It starts under the hood
Towing places a huge demand on a truck's powertrain. It requires a powerful and torquey engine, a decisive transmission and enough cooling capacity to embarrass the Fonz. Above all, it needs to be reliable.

A common-rail diesel fuel system and piezo-type injectors have been adopted for the new International Harvester-built diesel V8, measures meant to sidestep the troublesome durability record of fuel systems in previous PowerStrokes and also help assert more precise control over air emissions. Apparently IHC isn't out of the woods yet with its newly designed engine, as a handful of F-450s equipped with the turbodiesel had an issue with flames spewing from the exhaust and Ford has recalled a number of trucks to reflash the programming for the engine controls.

The jury might still be out on the new PowerStroke V8's durability, but this engine didn't hiccup once during its time with us. And we weren't gentle with it. We borrowed the largest, heaviest trailer we could find, added more weight, hooked it up to the F-450 and then hauled it up a steep 11.5-mile grade in dry, desert heat.

Running with the devil
To test the F-450's chops as a towing machine, we targeted its load at 80 percent of the F-450's 33,000-pound Gross Combined Weight Rating (GCWR). Fleetwood Enterprises of Riverside, California, loaned us the beefiest trailer in its GearBox series, a 39-foot, three-axle "Wide Body" toy hauler.

Strapping our 3,840-pound Hyundai Azera long-term test car into the hauler as ballast gave us a total trailer weight of 17,140 pounds. Once we factored in the F-450's 9,360-pound as-tested weight plus occupants, the entire rig checked in at 81.4 percent of the truck's GCWR.

Not only is this a hefty load to lug, but the hauler's billboard-size 111 square feet of frontal area induces considerable aerodynamic drag at speed. Ford warns that a frontal area that exceeds 60 square feet significantly degrades towing performance, meaning our rig is a helluva burden. Think of it as a luxury-lined parachute filled with lead shot.

Making the grade
Our test loop's aggressive grade represents some of the toughest towing conditions that owners are likely to encounter. It's hot, long, and averages a nearly 6.0 percent grade for 4 of its 11.5 miles. We set the cruise at 60 mph in the 90-degree-F conditions and let the grade do its work.

We expected the F-450 to labor under these conditions, but it soldiered up the grade with little protest. In this environment the F-450's turbodiesel V8 excels. The engine's 350 horsepower and 650 pound-feet of torque are well matched to the five-speed automatic transmission and the short 4.8:1 rear-end ratio. A hovercraft-grade auxiliary cooling fan easily regulated the engine's coolant temperature and kept us in chilly, air-conditioned comfort during the climb. We didn't observe any hunting between ratios by the transmission.

Under these conditions, the F-450 averaged 50 mph over the entire 11.5-mile grade and touched a low of just over 40 mph at the road's steepest pitch. This is no small feat, considering we breezed past an open-windowed Dodge Ram towing a much smaller trailer at the crux of the climb.

On the open freeway, there was little to indicate the F-450 was towing at all. The tongue weight settled out the ride quality, though the rig's fifth-wheel hook-up no doubt damped most of the tail-wagging-the-dog effect. The powertrain just hummed along, seemingly oblivious to the small house leeched to its backside. Our fuel economy over the course of towing 520 miles (including our hill sprints) averaged 6.3 mpg.

Flooring it from a standstill revealed only a brief flat spot in the V8's power delivery before the twin turbos, routed in series, spooled up to a max of nearly 40 psi. We clocked the F-450 at 10.8 seconds from zero to 60 mph at the track, a performance that slipped to 32.6 seconds while towing. This is still rapid enough to merge into freeway traffic without getting sweaty palms.

Not just for grimy jobs
You never forget you're driving a machine whose sole reason for existence is to haul loads, but the F-450 sans trailer rides better than its Herculean tow rating suggests. Credit the new, longer rear leaf springs. At full steering lock, the F-450's front wheels also turn a full 45 degrees, delivering an unexpected level of maneuverability.

Ford has revamped the interior for the new F-450, and it's a substantial improvement over that of the F-350 King Ranch we tested last year. The F-450's seats are vastly more comfortable and they're a welcome improvement over the balloonlike ones in the older truck. Meanwhile, wind and road noise within the cab are notably subdued, and diesel clatter is suppressed better than in the Duramax-equipped Chevy Silverado, itself a very refined turbodiesel pickup.

Serious truck guys will appreciate the new cab's factory-fitted controller for the trailer brake as well as dual power-extending mirrors with large spotter's mirrors. The functional improvements accompany an overdone "tough truck" styling theme for the interior, complete with blinding chrome bezels and corrugated plastics apparently inspired by a bedliner.

No test of the F-450 would be complete without mention of the deployable tailgate step. On paper, this struck us as a bit silly. One look at the F-450's high-bustle tail in person, though, and the step makes perfect sense.

Like Binaca for diesel
A few years ago, the diesel community was up in arms over the stringency of the upcoming emissions standards, which threatened to be the death knell of diesel. Ford addressed these concerns with an oxidation catalyst, particulate filter and a precise fueling strategy. Together, these measures are instrumental in making the PowerStroke turbodiesel stinkless.

The caveat is that these emissions control devices require ultralow-sulfur diesel (ULSD) fuel in order to remain healthy. The EPA reports that 85-90 percent of the diesel pumps in the U.S. currently dispense ULSD, and those pumps must carry a sticker saying so. There's no guarantee, however, that the dusty pump in the middle of nowhere dispenses ULSD.

At $56,920, the Super Duty is a serious commitment to towing. Considering the ease with which it tackles loads that would tax lesser rigs, it's money well spent.

The manufacturer provided Edmunds this vehicle for the purposes of evaluation.