Words by Mike Levine, Mark Williams and Kent Sundling, Photos by Ian Merritt
We carefully chose a combination of real-world and closed-course locations to test the trucks. We used our own GPS-based Racelogic VBOX test kit to record performance and geographic data.
A significant part of our testing involved comparing all three trucks head to head at wide open throttle, with and without the heavy trailers. Why would we do that? HD pickups aren’t muscle cars, after all.
At wide open throttle, we can measure the trucks at 100 percent of their maximum power ratings, something we can’t usually do for more than short periods when we’re on extended drive routes over public roads. It’s also one of the only ways to empirically separate the trucks’ performances from each other – which, you’ll see, is measured in the tenths of seconds.
We traveled to Chrysler’s Arizona Proving Grounds (formerly owned by Ford) in Yucca, Ariz., about halfway between Kingman and Lake Havasu City. There, we set up camp on a multiple-acre stretch of flat tarmac. It's perfect for determining time and speed performance over a fixed distance, unloaded and loaded.
What's the point of running heavy-duty pickups through the quarter-mile? Isn't the job of a one-ton rig simply to deliver a heavy load or haul a trailer from Point A to Point B? You'd be correct, except for the one circumstance where the quarter-mile test almost always comes in as a handy measurement: merging into highway traffic.
Because of strong winds, we measured zero-to-50-mph times while towing trailers and zero-to-60 times when the trucks were empty.
There were headwinds from the south gusting 15 mph to 25 mph. To account for this, we ran each truck six times – three sets of back-to-back runs in north and south directions. We averaged each north-south pair to calculate the acceleration times and are presenting the time and speed of the fastest sets.
Weather conditions recorded at Chrysler's Arizona Proving Grounds on July 13, 2011. The blue lines indicates each truck's testing start time.
For all testing, the same driver sat behind the wheel. Traction control was turned on and air conditioning was off, for maximum performance. Tow/haul mode was on when the trucks were loaded and off when they were empty. The exhaust brakes on both the Ram and GM trucks were also enabled when loaded. The Ford’s exhaust brake is automatically enabled when the truck is in tow/haul mode. Towing mirrors were at full extension or in the trailer-towing position when we towed and retracted or folded down when empty. Acceleration runs started by lifting the right foot off the brake pedal and pressing the accelerator instead of holding the brake down to build up engine rpm before launching.
Even though we had three identical new trailers behind the trucks, only one trailer was used for testing to reduce variables.
The Ford F-350 was the fastest truck through the quarter-mile when pulling a trailer, but just barely. It ran 1,320 feet in 25.63 seconds at 55.13 mph, almost a quarter-second faster than the GMC Sierra 3500, even though the Sierra finished with a higher speed of 56.75 mph. The speed and time charts show why.
The Ford F-350 carried a higher speed through the first 600 feet before the Sierra 3500 started to outpower it, but by then it was too late. The Sierra couldn’t close the gap between the two, even though the gap was shrinking.
The Ram 3500 demonstrated a consistent pattern throughout all of the acceleration testing, which we could also feel by the seat of our pants. Hitting its peak torque at 100 rpm sooner than its competitors and its 4.10 rear axle helped give the Ram fast starts off the line – usually first or second through the first 400 feet – but its lack of horsepower seemed to hurt the Ram over the full quarter-mile. It finished the distance in 26.39 seconds at 53.46 mph. Overall, the Ram stuck very close to the Ford and GMC one-tons.
The Ford Super Duty’s coolant temps ranged between 208 and 219 degrees, and transmission temps hovered around 207. The F-350’s transmission was able to shift to 4th gear, finishing the runs at about 2,900 rpm, about 100 rpm above peak horsepower. We didn’t encounter any rear axle hop like we have in the past, but we could feel a surge of power move from the front of the truck to the rear as it launched in wide open throttle. In general, the Super Duty’s six-speed had the smoothest shifts of the trucks – something we also saw in performance tests and highway driving.
The Sierra’s coolant temp stayed a consistent 210 degrees while transmission temperatures rose from 158 on the first run to 189 at the end of the third. A cooling fan kicked in whenever coolant went above 210 degrees until that target temp was reached. The Sierra held onto 1st gear the longest of the trucks, holding it until 3,000 rpm before upshifting to 2nd. It was the only truck that made it to 5th gear at the quarter-mile mark, upshifting at 3,200 rpm in 4th and immediately dropping to 2,300 rpm in 5th.
The Ram HD’s coolant ranged between 204 and 222 degrees, but the truck’s fan turned on in the low 220s and efficiently lowered the temperature to 210 in a few moments. Gearbox heat ranged from 199 degrees during the first run to 215 after the last. In general, rpm numbers from the Ram’s inline-six were lower than its eight-cylinder competitors. The Ram made it to 4th gear in the quarter-mile. There were occasional hard upshifts.