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Diesel 2011 F-450 XLT 4×4 Crew Cab Long Wheelbase Dual Rear Wheel — Towing 24,000 pounds
After towing the 9,900-pound trailer, we hopped in for a ride along in the mighty F-450 pickup with a 24,000-pound gooseneck trailer hanging off its back end. That's almost three times the weight of the truck, and it requires a commercial driver’s license to legally move on highways.
Photo by: Sam VarnHagen/Ford Motor Co.
Up front, the F-450 is unique in the Super Duty pickup lineup. It features a larger and wider Dana 60 axle, beefier coil springs, and stronger linkage arms and knuckles that give it better maneuvering capability than an F-350 with the stock Class 3 twin-coil narrow-track front suspension.
Before we headed up Yarnell Grade, we cycled through the gooseneck-towing checklist in the trip computer. It provided instructions to check that the hitch was properly latched, the trailer landing gear was up, all of the connectors were secure and any wheel chocks were removed so the trailer could roll forward. The trip computer also was set up to keep track of how much mileage was on the trailer — helpful for maintenance later.
The truck started out slowly, but once it got going it maintained a steady rhythm up the hill. Coming down wasn't a problem, either. All the same tricks we used in the smaller Super Duty were applied to keep the F-450 in check.
We'll have to save our hands-on impressions of the F-450 for a thorough test later this year.
Gasoline 2011 F-250 XLT 4×4 Crew Cab Long Wheelbase Single Rear Wheel — Hauling 1,000 pounds
The next truck we steered was one trim level below the F-250 we used for the hill climb. It was equipped with the new 6.2-liter V-8 gas engine, a 3.73 rear axle and carried 1,000 pounds of concrete mix in its cargo box.
Photo by: Sam VarnHagen/Ford Motor Co.
The single-overhead-cam 6.2-liter V-8 is built solely for truck applications. It features two spark plugs per cylinder and dual, equal variable cam timing. It's also E85 flex-fuel compatible.
For now, the 6.2-liter V-8 is shared with the F-150 SVT Raptor, where it's rated a higher 411 hp and 434 pounds-feet of torque because the light-duty version uses a slightly different camshaft for its heads and it's under 8,500 pounds GVWR. Even with just two valves per cylinder, there's still enough airflow to make 62 hp per liter compared with 58 hp per liter in the four-valve 6.7-liter diesel.
The 6.2-liter V-8 works at modest 9.8:1 compression ratio to help keep the combustion chamber cool when it's running hard. It's an attempt to strike a balance between loaded and unloaded mileage. A higher ratio would cut into fuel economy because the spark timing would have to be retarded to prevent knock as heat built up at wide-open throttle, such as when you're towing a trailer up a mountain.
In contrast to the four final-drive ratios available for the diesel, there are only two available for the 6.2-liter V-8 — 3.73 and 4.30. Before buying the gas engine, you're going to need to think a bit harder about how the truck is going to be used over its lifetime so you can balance fuel economy against pulling performance. There's a 3,000-pound spread between the maximum fifth-wheel towing amounts depending on the ratio. It's 12,700 pounds with the 3.73 and 15,700 pounds with the 4.30.
Like the diesel, the 6.2-liter V-8 has been tested extensively. According to Ford V-8 engine chief Mike Harrison, more than 5 million miles of testing has been done on the engine before going to production. It's also been race tested in Raptor during the Baja 1000 and the 2009 Best in the Desert off-road racing series.
Photo by: Sam VarnHagen/Ford Motor Co.
As we expected, the 6.2-liter V-8 felt much stronger than the old 5.4-liter V-8, but we're still big fans of the diesel-like performance of the 6.8-liter gas V-10 that continues only in the Super Duty Chassis Cab trucks for 2011.
The 6.2-liter packed plenty of power when we lit up the truck at wide-open throttle from a full stop to merge onto a highway. Approximately 80 percent of peak torque is available at a low 1,000 rpm and 90 percent is available at 2,000 rpm.
After driving the diesel most of the day, it was quite a change to hear the V-8 roar as the RPMs spun much higher and faster (around 5,000 to 5,500 rpm) than they ever would in the 6.7-liter truck (around 1,800 rpm to 2,600 rpm).
The 6.2-liter engine seems to be a good start to a motor that can only improve over time. Since it's an overhead-cam architecture, new cylinder heads could be swapped in with four valves per cylinder, dual overhead cams and twin independent variable cam timing to improve fuel economy a few percent and increase power over 455 hp, according to Harrison.
Gasoline 2011 F-250 XLT 4×4 Crew Cab Long Wheelbase Single Rear Wheel — Towing 9,000 pounds (This section written by Kent Sundling for PickupTrucks.com)
The low 3.97 first gear in the six-speed got the 6.2-liter gas V-8 F-250 and 9,000 pound trailer off to a smooth start with a 3.73 rear axle. That's not a final drive ratio that we'd normally use to tow a moderately heavy trailer. A 4.30 rear end is optional.
Climbing the 7 percent grade, the 6.2-liter V-8 howled pulling the trailer near its 6,000 rpm redline. Without a trailer, the 6.2-liter has as nice low torquey throttle sound, but under load the engine is louder in the cab than the new diesel.
Photo by: Sam VarnHagen/Ford Motor Co.
It wasn't easy to evaluate the gas engine right after flying up the hill using the powerful diesel. The all-new 6.2-liter gasser felt stronger than 5.4-liter V-8 gas engine it replaces, with some of the performance improvement credited to the new 6-speed automatic transmission's more efficient gear spacing.
6.2-liter throttle response is good with a trailer, but it's not the old 6.8L V-10 gas engine that's still available with the DRW cab and chassis but only with last years five-speed 5R110 automatic transmission.
Overall, towing a 9,000 pound trailer with 3.73 rear axle ratio at close to 4,500 feet elevation and side winds wasn't fast but it provided acceptable acceleration for uphill towing.
