Power Pullers --The Ultimate Tow Test: Part Two

Level Ground Testing

Mike Levine
Feb 22, 2008
As you'll recall from Part I, we gathered up the entire crop of 2007 heavy duty pickups for the ultimate Power Pulling Tow Test. Dodge, Ford, and General Motors provided us with three gas engine, single rear wheel, three-quarter-ton trucks, plus three diesel engine, dual rear wheel, one-ton trucks, and Ford's ultimate F-450 one-and-one-half-ton Super Duty.
Photo 2/35   |   power Pullers Part Two Three Quarter Ton Ford Vs GMC
The first round of testing performed by our team of truck journalists and independent data collectors, hired from Ricardo Engineering, was level ground loaded and unloaded runs at Milan Dragway, just outside Detroit. The track features an IHRA sanctioned 1/4-mile dragstrip. It's perfect for determining time and speed performance over a fixed distance.
Some may ask, what's the point of running heavy duty pickups through the 1/4-mile? Isn't the job of a three-quarter or one-ton rig to simply deliver a heavy load or haul a trailer from point A to point B? You'd be absolutely correct except for one circumstance where the 1/4-mile test almost always comes in as a handy measurement - getting on the freeway.
Photo 3/35   |   power Pullers Part Two one Ton Trucks Dodge Vs Chevy
The tests we performed represent a reasonable scenario for those drivers interested in learning how quickly they can accelerate up to 60-mph plus to join the flow of traffic on a freeway, without holding other drivers up behind them or causing an unsafe situation in a slow moving vehicle towing a trailer.
All the runs at Milan were carried out at wide open throttle (WOT) in the normal 1/4-mile direction, using the right hand lane, starting from the regular start line. Every run was initiated by following the staging and countdown lights on the Christmas tree from a dead stop.
To make Milan a bit more interesting, we invited all the manufacturers to send as many PR and engineering folks as they wanted to observe the testing first-hand. Chrysler, General Motors, and Ford Motor Company all took us up on that offer and had at least one person onsite during the races.
Photo 4/35   |   power Pullers Part Two one Ton Trucks Ford Vs Chevy
In the pictures that accompany this story, you'll see the trucks racing each other. However, our data collectors only gathered metrics and information from one truck at a time using a $50,000 Oxford Technical Solutions.
All the tests were conducted in 4 wheel drive (high range mode) with tow-haul engaged when towing, and disabled when not towing.
A minimum of three runs was carried out in each configuration tested. The fastest runs are presented in the results.
We didn't have time but an interesting test would have been to have done these runs for three days, to see how the adaptive computer programs would have changed acceleration and shift points in the transmissions. Though under load, such as a trailer, we may have been close to our top parameters.
Tests
Three-Quarter-Ton 1/4-Mile Assessment
One-Ton 1/4-Mile Assessment
One-and-One-Half-Ton DRW Crew Cab 4x4 Diesel Pickup
Three-Quarter-Ton 1/4-Mile Assessment:
Out of the three-quarter-ton trucks, it's GMC's new 6.0-liter Vortec Max V8 / 6-speed heavy duty transmission combination that has the best setup for the level 1/4-mile. The gear ratios perfectly match the engine's torque curve.
What's interesting, though, is Dodge Ram's 5.7-liter HEMI transmission gearing. Both our Ram and Sierra had 3.73:1 final drive ratios, but check out second gear (see transmission ratio chart). It's much higher in the Ram, 1.67:1, than in the Sierra, 2.36:1. There wasn't much of a time difference from 0 to 40-mph between the trucks unloaded, but as soon as the 10,500-pound trailer was hooked up the 0 to 40-mph delta grew to almost a full second. The HEMI fell behind because it lugged against that 1.67 ratio. We think the results would have been much closer if the HEMI had the same, or near-identical, spacing as the Vortec Max's cogs. By the way, Dodge is the only truck of the three that uses the same transmission with their gas engines in 1500, 2500 and 3500.
Photo 5/35   |   power Pullers Part Two Three Quarter Ton Dodge Vs Ford
When we compare the V8 powered GMC Sierra 2500 against the V10 powered Ford F-250, the 4.30 final drive ratio in the Super Duty handicapped the truck unloaded but materially helped it while towing - at least at the start of the run. The GMC and Ford trucks swapped the lead with each other twice, up to around 50-mph, before the GMC's six-speed transmission and its excellent gear spacing once again proved decisive - enabling a V8 to beat a V10.
Photo 6/35   |   power Pullers Part Two Three Quarter Ton Ford Vs GMC
Towing a trailer tells a different story with transmission gear spacing and final drive ratios - which is the reason final drives are lower in three-quarter-ton and one-tons versus half-tons.
When you buy a heavy duty today, one of the few performance decisions still under your control is determining the final drive ratio - particularly for a gasser. There isn't a dramatic difference in fuel economy between a 3.73 and a 4.10, but towing acceleration and less transmission downshifting are going to make the 4.10 a better choice for a gas truck. If you're purchasing a diesel, it's not going to be as important.
Photo 7/35   |   power Pullers Part Two Three Quarter Ton Ford Vs GMC
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Photo 9/35   |   power Pullers Part Two Three Quarter Ton GMC Vs Dodge
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Photo 13/35   |   power Pullers Part Two Three Quarter Ton GMC Vs Dodge
One-Ton 1/4-Mile Assessment:
In contrast to the three-quarter-ton gas trucks, Dodge had a better story to tell with its six-speed 6.7-liter Cummins inline six diesel.
Photo 14/35   |   power Pullers Part Two one Ton Trucks Dodge Vs Chevy
With the earliest torque curve among the one-tons (1,400-rpm versus 1,600-rpm in the Duramax and 2,000-rpm in the Power Stroke) and a 4.10 rear axle (versus 3.73 in the Ford and Chevrolet) the Ram owned the unloaded quarter mile. What's interesting to see in the results though is that by the very end of the run the other two trucks were really putting pressure on the Ram. The Dodge was the slowest of the three as it crossed the finish line. So, while the 4.10 definitely helped the Ram 3500 win the quarter-mile, the other two trucks were just coming into their own at the checkered flag.
The towing quarter-mile started out much the same way, but in this scenario the Ford and Chevy caught the Ram and were able to out muscle the Cummins-powered pickup before the end of the drag.
Photo 15/35   |   power Pullers Part Two one Ton Trucks Dodge Vs Chevy
During the summer, GM invited us out to their Milford Proving Grounds to compare their full size pickups head to head against competitors in each of the full size truck segments. One of the bouts pitted a Silverado 3500 and an F-350 against each other in a hill climb. We saw the same pattern from that contest repeat itself on level ground. The Duramax's lower torque peak (1,600-rpm v. 2,000-rpm) and its higher second gear (1.81 v. 2.22) helped the Chevy initially out-power and out-hustle the Power Stroke down the track from 0 to 50-mph. But look at the final quarter-mile times and speeds, the Power Stroke made up for lost ground and was almost able to close the gap against the Duramax.
Photo 16/35   |   power Pullers Part Two one Ton Trucks Dodge Vs Chevy
But what's most amazing of all, and this was something echoed by the OEMs on hand at Milan, was how close in performance all the diesels were to each other versus just a few years ago at the turn of the century. Now it takes electronic GPS devices to measure the pecking order - it's that close. Good news for any consumer regardless of what pickup you buy.
Today reliability, dependability, and cost of ownership should be the major determining factors when purchasing a diesel.

Photo 17/35   |   power Pullers Part Two one Ton Trucks Dodge Vs Chevy
Photo 18/35   |   power Pullers Part Two one Ton Trucks Dodge Vs Chevy

Photo 19/35   |   power Pullers Part Two one Ton Trucks Dodge Vs Chevy
Photo 20/35   |   power Pullers Part Two one Ton Trucks Dodge Vs Chevy
Photo 21/35   |   power Pullers Part Two one Ton Trucks Ford Vs Chevy
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Photo 26/35   |   power Pullers Part Two one Ton Trucks Dodge Vs Ford
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One-and-One-Half-Ton DRW Crew Cab 4x4 Diesel Pickup
Like we said in Part I - this truck is in a class all its own.
We're pretty sure that the Ford F-450 and its 45-foot, 20,000-pound fifth wheel is the longest and heaviest vehicle ever to run the quarter-mile at Milan.
If you've run a bigger, weightier rig down Milan faster than our scores below, let us know. We'll buy you a burger and the first round of drinks at Miller's Bar in Dearborn next time we're in Michigan. Just don't embarrass us by ordering a salad!
As you can see from the time and speed data, we came pretty close to the F-450's gross combined weight rating (GCWR) and the truck was able to hit a reasonable freeway entry speed within a quarter mile. You'll have to fend for yourself though trying to figure out how to wedge the 45-foot trailer into traffic. Better flick the turn signal on early!
Check back soon for Part III, as we head for the hills for some tough incline testing.
Photo 31/35   |   power Pullers Part Two one And One Half Ton DRW Crew Cab 4x4 Diesel
Photo 32/35   |   power Pullers Part Two one And One Half Ton DRW Crew Cab 4x4 Diesel
Photo 33/35   |   power Pullers Part Two one And One Half Ton DRW Crew Cab 4x4 Diesel
Photo 34/35   |   power Pullers Part Two one And One Half Ton DRW Crew Cab 4x4 Diesel
Photo 35/35   |   power Pullers Part Two one And One Half Ton DRW Crew Cab 4x4 Diesel

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