Chevy vs. Ford in Heavy-Duty Rumble in the Rockies

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Photos courtesy of Diesel Power, General Motors

Over the summer, we published the results of our nine-truck Heavy-Duty Shootout, where we selected the Chevy Silverado 2500 HD and GMC Sierra Denali 3500 HD as our two top picks in the three-quarter-ton and one-ton diesel categories. But our readers raised two important points.

The first point was that we didn't test Ford’s "Job 2" engine calibrations for the all-new 6.7-liter Power Stroke V-8. The free powertrain software update for 2011 diesel Super Dutys boosts the ratings from 390 horsepower and 735 pounds-feet of torque to an astonishing 400 hp and 800 pounds-feet, eclipsing GM’s 6.6-liter Duramax V-8 rating of 397 hp and 765 pounds-feet. We didn't test the re-rated Ford trucks because they weren’t available at test time.

The second concern was about the quarter-mile and hill-climb acceleration tests, where we measured performance over relatively short distances pulling 10,000-pound and 12,000-pound trailers. The tests were enough to provide consistent evidence of the strength of GM’s powertrain, but some thought Ford’s diesel and new six-speed would have beaten the Chevy and GMC if the distances were greater.

Specs

We didn't disagree with these two points and wondered about both ourselves, even though we know our Shootout comparison tests are the most rigorous exams you’ll find to judge pickup truck capability.

The challenge

Then, in late September, Chevrolet challenged Ford to a real-world showdown in the Colorado Rockies, similar to the Mike Rowe head-to-head towing competitions that Ford has used to promote the capabilities of its F-Series pickups. Ford declined, but the bowtie boys decided to press forward and invited PickupTrucks.com and Diesel Power magazine to witness the test.

We agreed with a few conditions: Chevrolet had to use test trucks purchased off the lot from Chevy and Ford dealers and the Super Duty had to have the 400/800 power ratings. They couldn't come from GM's captive test fleet and the trucks had to be as "apples-to-apples" as possible when it came to features and equipment. While Chevrolet originally wanted to test three-quarter-ton HD pickups — the heart of the HD market — we had to use one-ton trucks because that was the only way to match equivalent rear axle ratios of 3.73. We also had to drive and instrument the trucks to measure the results ourselves. Chevy reps would be along for the ride.

Chevrolet met those conditions, and we picked up two brand-new dealer-bought HD pickups in Detroit. The 2011 Chevrolet Silverado 3500 LT four-wheel-drive crew cab came from Mike Savoie Chevrolet in Troy, Mich., with 8 miles on the odometer and 0.9 hours on the engine meter. The "Job 2" 2011 Ford F-350 Super Duty XLT four-wheel-drive crew cab was sold at Harold Zeigler Ford Lincoln in Elkhart, Ind., and driven to Detroit by a third-party fleet service. Two Diesel Power staffers drove the trucks 1,250 miles to Denver.

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How equivalent were the trucks? They were probably the most evenly matched HD pickups we've tested. Besides the same rear axle ratios, the $54,805 8,440-pound Ford was just $65 and 220 pounds more than the $54,740 8,220-pound Silverado. Both lacked fancy equipment such as leather seats, navigation systems and sunroofs.

The location and the load

We knew we needed a real-world place to test both trucks, so we chose the eastbound ascent from Dillon, Colo., to the top of Eisenhower Pass on Interstate 70. It’s perhaps the toughest stretch of road a loaded truck will encounter on a major cross-country highway – call it the Nürburgring of pickup trucks because nearly every bit of towing and braking hardware is stressed to its max for multiple miles at a very high altitude.

The grade starts at about 5 percent for two miles and increases to about 7 percent for the remaining six miles, to the entrance to the Eisenhower Tunnel, the highest vehicular tunnel in the U.S. Despite that lofty elevation, an average of more than 30,000 vehicles crossed in both directions each day last year, according to the Colorado Department of Transportation.

We also needed a heavy trailer that the trucks could share. Chevy lined up a 6,500-pound gooseneck with three 4,140-pound pallets of flagstone lashed to the flat bed for a grand total of 18,920 pounds. That brought the gross combined weight rating for the Chevy to 27,140 pounds before four adult males jumped in and added another 800 pounds, for a grand total of 27,940 pounds, or 96 percent of the Silverado’s maximum GCWR. The total for the Ford F-350 was 28,160 pounds, or 94 percent of the Super Duty’s maximum GCWR.

Eisenhower

For our test, we used a stretch of I-70 that started in Dillon at 8,776 feet and ended at exactly 11,000 feet, rising 2,224 feet over 7.6-miles (approximately 40,000 feet).

But we didn’t just time the trucks up the grade. We also evaluated their exhaust-brake performance while heading the opposite direction back to Dillon with the nearly 19,000-pound trailer pushing these monster HDs downhill. An exhaust brake saves on brake and transmission wear by clamping down the engine’s turbo vanes, creating back pressure to engine brake the truck. It also reduces the potential for brake fade during long descents, increasing downhill safety while towing and overall wheel brake life.

Where’s Ram?

If you were wondering where the Ram 3500 is in all of this, it wasn't included because these weights exceeded its 24,500 maximum GCWR by more than 2,500 pounds. It wouldn’t have been safe or responsible to test the truck in these conditions.

To help manage these astonishing weights, which we couldn’t have imagined a decade ago, we used a professional driver with a commercial driver’s license paid for by Diesel Power Magazine. Please see Diesel Power for the driver's bio.

Hill-climb test

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Each truck was run up the grade in Tow/Haul mode starting in four-wheel drive for max traction in the cold conditions and switching to two-wheel drive at approximately 30 mph. The fastest time was used for the comparison.

We ran the Ford four times. The first two runs were with only three adult males to offset the Chevy’s 220-pound curb weight advantage, and the last two runs had all four of us in the trucks. The fourth run was Ford’s fastest time. Two-hundred-twenty pounds doesn’t matter much when you’re pushing almost 15 tons against gravity.

Temperatures ranged from 5 degrees to 18 degrees, according to the trucks’ outdoor temperature readouts. It was so cold that neither truck’s fan turned on, though the next day, at just 35 degrees, both trucks’ fans turned on frequently to cool the engines.

The trucks were at a dead stop before each run. The driver ran wide-open throttle from start to finish. We didn’t encounter any traffic on the road during the late-night climbs.

We used our own GPS-based Racelogic VBOX test kit to record performance and geographic data.

The Ford F-350's best time up the grade was 10 minutes, 46.8 seconds at an average speed of 42.41 mph. The top speed was 58.5 mph, and it happened just before the point where the grade increased from 5 percent to 7 percent.

Time-comparison

This chart shows each truck's speed climbing the 7.6-mile grade against the clock. The Silverado reached 11,000 feet in 518.2 seconds and the Ford finished in 646.8 seconds.

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Distance-comparison

This chart shows the speeds of both trucks relative to each other over the 40,000 foot (7.6 mile) run to 11,000 feet in elevation. Note how similar the speed patterns are for each truck as the grade changes throughout the climb.

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Average speeds

The Chevy Silverado was significantly faster. It finished more than two minutes ahead of the F-350, in 8 minutes, 38.2 seconds. Average speed cruising up to 11,000 feet was 53.63 mph, 11.22 mph faster on average than the Ford. The Chevy’s top speed was 67.38 mph for a few seconds before the grade changed from 5 percent to 7 percent.

The Chevy and Ford had similar performances at the start of their runs. The Ford clicked off the quarter-mile in 31.25 seconds at 45.13 mph, and the Chevy ran the same distance in 28.93 seconds at 50.3 mph. But the Chevy was already coming on like a freight train at that point. It took the Silverado 28.56 seconds to go from zero to 50 mph, while it took the Ford 42.02 seconds.

Both trucks ran the first part of the grade in 4th gear and dropped down to 3rd gear for the rest of the climb.

Exhaust brake test

For the exhaust brake test, we exited Eisenhower Tunnel westbound and set both trucks’ speed to 55 mph in 4th gear. The Silverado has a push-button-activated exhaust brake that can work in or out of Tow/Haul mode, while the Ford’s exhaust brake is automatically enabled when the truck is in Tow/Haul. Unlike the Duramax, the Ford’s exhaust brake can't be turned off by the driver.

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We wanted to see which truck required the least amount of wheel brake application, so when speeds reached 60 mph, the driver applied his left foot to the brake to slow down the truck to 52 mph to start the cycle again.

The difference in exhaust brake performance (echoing the much shorter test performed in the HD Shootout) was starker than the difference towing up the hill.

After four runs in the Ford, we had to manually slow the truck between 11 to 14 times during each descent to keep it from exceeding 60 mph. Ford’s exhaust brake seemed to have minimal effect slowing the rig and keeping our driver from getting that “white knuckle” feeling you don’t want to have when your 15-ton rig is rolling down a hill. Ford’s six-speed transmission did a nice job downshifting from 4th to 3rd gear after the foot brake was applied to help slow things down.

The Chevy was a superhero on the descent. It was like Superman digging his feet into the pavement to stop a runaway locomotive. In three downhill runs, we averaged one to two manual brake applies. That’s it. It consistently hung in at a steady 58 to 59 mph and stayed at that speed for miles. When we applied the foot brake after the first time, the Chevy downshifted from 4th to 2nd gear near redline at 52 mph and kept shedding speed until we tipped into the throttle to get back into 3rd and started picking up speed again. We never shifted down to 2nd gear in the Super Duty, slowing the truck to 52 mph.

At the turnaround point in Dillon to start each test cycle, the most telling aspect of our exhaust brake test was the strong smell of hard-worked brakes in the Ford and the absence of that smell in the Chevy. That doesn't just save on brake wear. It saves on frayed nerves as well.

Summary

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In short, the Chevy Silverado's performance surprised everyone, given Ford's higher stated power figures for the 6.7-liter Power Stroke. Finishing two minutes ahead of the Super Duty over a 7.6-mile grade at more than 90 percent GCWR is nothing short of a dominant showing for Chevy. The exhaust brake performance is perhaps even more telling and welcome news for frequent heavy towers.

What accounts for the significant performance differences between the Chevy and the Ford in this comparison? We originally thought it might be a gap in the Power Stroke's high altitude engine calibrations, which optimize combustion performance based on driving conditions, but now we think its part of the nature of the 6.7's unique single sequential turbo.

Ford's turbo features a single turbine and two compressors placed back-to-back. It's possible that Ford's siamese compressor design is losing some efficiency the higher it climbs.

For braking, both trucks depend on variable geometry fins that surround the turbine. They clamp down to restrict exhaust flow and create back pressure in the engine to slow the truck down. The Duramax appears to be able to clamp down more strongly than the Power Stroke.

Interestingly, Honeywell subsidiary Garrett is the same turbo supplier for both diesel engines. 

Regardless of the cause of the performance gap between these two incredibly capable HD pickups, we reaffirm the results of our 2010 HD Shootout in the real world. There’s no question that GM's latest diesel pickups are the performance leaders in the class. Chevy doesn't just run deep. It runs high as well.

For more information and a second take on this test, be sure to check out Diesel Power.

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All of the data we collected during the Rumble in the Rockies has been provided to Ford and General Motors for their review. PickupTrucks.com and Diesel Power Magazine paid for our own travel and lodging expenses associated with this test. We were not compensated for any part of our participation by GM.

Comments

Great work! Next I'd like to see a fuel economy comparison between similar trucks towing hefty loads, maybe from Denver to Grand Junction for a nice mix in terrain. Perhaps trim a little off the loads used in this test so the Dodge can play too!

Well congrats to GM,
An although it's a tow comparison, people only buy these trucks for towing. Yea right!

The Government motors thing sure does get old! Suspension this, and altitude that....

Really, as everybody knows, people will still buy what they want. You can never overcome either manufacturers "old wives tales" when it comes to their cars or trucks performance numbers.

People keep calling this a "drag race" to the top of the hill, but this was nothing of the sort. Flooring these vehicles to the top of this steep hill is a necessary evil to maintain a decent speed! Obviously, those that argue differently have never experienced a hill like this. This climb is no joke.

As far as HD Diesel pickups are concerned, neither truck is a grand slam. The GM has an inferior interior (opinion). The Ford has the weaker engine and drivetrain, as this test proved.

What is Mike to do about all the hating? Just keep reporting the facts! Thats all you can do.

Better luck next year to Ford, as I am sure they will figure this out.


@ Mike Levine: Great test Mike, love the methodology of these comparisions, you guys are really covering the bases in terms of a fair test. One question I had is about transmissions temperatures. I know it was very cold during the test but out of curiousity, do you recall what the highest trans temps were for boths truck for the ascent with the trailer along with the downhill test. I know the Silverado has a trans temp guage (I own an HD), but not sure if the superduty has one if it did not come with the productivity screen).

The real winner in this test and the previous shootout for that matter is us the consumer. With Chevy and Ford competing this strongly for our business, producing pickups that can do what only medium duty trucks could do 15 years ago we all can buy more capable, harder working, more advanced trucks. I just bought a Ford F250 Power Stroke which is the 2nd Ford vehicle that I've owned and i had great luck with the first truck too. I just traded in my Chevy which was the 5th GM truck I owned and the only thing I ever did to any of the last 3 GM's was add gas, change oil and replace tires so my GM's were all great too. I feel very fortunate to know that I was able to shop Ford and Chevy and buy the truck that was the best price because both of them were able to do the job that I needed done competently. I hope that GM will have a baby Duramax powered Tahoe on the market when my F250 is paid off and I can own a Ford Pickup and Chevy SUV, both powered by diesels.

Where are Lou and Frank HA HA. GM is kicking some butt.

To you flatlanders complaining about this test, give me a break, this type of test is the only place in America that can give these trucks a challenge. Great work PICKUP-TRUCKS.COM!!!!

I have always been a Ford man, but I would love to own a 2011 duramax. When the duramax first came out in 2001 it was all right, but it really wasn't a powerhouse until the LBZ verson came out in, I believe, 2006. It took GM 5 years to really get it tuned just right. The 6.0 powerstroke, and common-rail cummins could out pull the duramax until then. From LBZ, to LMM, and now the LML, the duramax is a powerhouse! Now that the Duramax/Allison combo finally comes in a much beefier chassis for 2011 I think GM has a real winner. As much as I hate to admit it, great work GM!

Ford, how does that crow taste?

Good job Government Motors on finally getting more PR per taxpayer dollar and this is what you need for your ad campaign, not just alot of talk!!! I"ll still take the Super Duty.
Posted by: x007 | Nov 15, 2010 9:19:59 AM
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x007 well said. This is only part of the story,unfortunately there is more to a truck than just power-train. All you GM lovers should look under these trucks and see how a real truck is built. Yes for my tax dollars I would prefer to put them to better use than to fund somebodies dream of what use to be.

@Riders_89. What is looking under these trucks going to prove? That GM has a fully boxed frame, or that there is an Allison under there? Or that the Ford has an SFA and the second best drive-train? Whats your point. Don't hesitate to use your engineering degree to explain yourself.

To all you guys who think that GM is doing a great job with the Duramax and Allison Transmission need to start rephrasing. It's Isuzu who does a good job with Duramax. GM can't seem to engineer a good motor on their own, they need the Japanese to do it for them. Ford and Navistar International Corporation used to build the Power Stroke as one but Navistar couldn't hold it together and Ford had to start building the Power Stroke in house, but the Power Stroke has always been engineered and built by Americans unlike Duramax. Same thing goes with the transmissions. GM has to outsource and Ford doesn’t. Ford can tow more, has a bigger payload is safer and has all the features and goodies people want.

I think that’s why you see the Super Duty used as snow pushers, farm trucks, emergency vehicles, construction trucks, boat haulers, tow trucks, ect more then GM and Dodge.

Congrats to GM! All this hoobla about IFS or SfA is a bunch of crap. I have owned gm trucks for years on our ranch in south texas and have not had any problems with its performance. Its given me the same performance as ford or dodge but with a better ride and 4X4 traction. Hadnt had problems with torsion bars or saggy front end either. And at least my front tires didn't slant in like the fords did, i think they have corrected that problem though. Its just funny to have people go from one thing to the next on ford or gm. GM beats ford in the 2 shootouts and now the GM's front end is suddenly the target again along with taken bailout money. I bet u all have money in banks that have taken bailouts but you still bank there or a new bank that took bailout money. People are funny creatures, glad we all have different personalities.

Where was the damn Mahindra truck during this test.

Ouch I'm hurt. Its called durability. Top Dog all that this showed is HP and Braking maybe you should look underneath these trucks and see for your self looks like they used parts off of the 1500. Its just like going to a book store to buy a book hum they all look the same tell a story. Once you open the cover to see whats inside that's when you see the real story. Take these trucks up to Fort Murray,AB. where they use these truck for real everyday work over rough terrain and not just pulling up mountains. and drag racing up a mountain which everybody does everyday.

I just have say congrats to GM. They have a great powertrain combination, and this proves it.

About the bail outs, how many of you complaining about GM taking goverment money actually work as an automotive supplier. If you did you would realize that a huge number of suppliers would have gone out of business if GM did. That in turn would have disrupted the supply chain to nearly every vehicle sold in the US. It is a huge domino effect that many people do not understand.

In 2007, Ford did take loans. Companies have been taking goverment loans since the great depression. It is no different that taking out a mortgage or a car loan.

@Bryan. Yawn. Why reinvent the wheel with transmissions? Allison is the best, and GM uses them. You should do some research on where the current generation Dmax's are designed and built. Heck, at least Ford and GM trucks are assembled in the US. Well, at least after Ford gets their all new, in house designed (wink) Powerstroke shipped up from Mexico to the US truck assembly line.

I have seen every vehicle you mentioned in GM and "Ram" trim as well, so what is your point?

@riders_89. PS, I have looked under both trucks. Even set em side by side. They both have high, and low points. Nothing I wouldn't trust from either manufacturer.

I live and work on a "mountainous" USAF installation, so I get to see all these trucks in action in their fleet form. Please, spare me the "durability" claims, as most of the stories, along with my own, are like old wives tales. Every manufacturer has plenty of them.

I recently watched a Border Patrol episode where the Agent claimed all 3 manufacturers can't make a vehicle that holds up in extreme conditions. I believe him because he may have had to get into or out of a few hairy situations. Other than that, yours (and my) durability claims are just here-say.

Hilarious!!!! All the talk about fords new powerstroke. More like power"choke"!!! Call GM what u want but they sure kicked some ass!

Congrats GM! Knew you could do it! On another note, congrats to Ford as well! If it weren't for Ford pushing the limits, GM would still be stuck with the 6.2 and 6.5.

Great test of two great trucks. I have been a gm fan since I was 14, but I have the utmost respect for all the hard-working trucks on the road. Once again, congrats GM, and Ford, great job as well.

@Top Dog:
My point was that you see more Fords then GM's and Dodges as these type of vehicles. I know for a fact that the Power Stroke is built in Huntsville, Alabama. Thats what it's says on the engine crate when received at KTP. You need to get your facts straight and stop talking out your a**. Isuzu is the #1 truck and diesel maker in Asia and Europe, so GM had to get the best to try and beat the best. Duramax might be made in Moraine, Ohio but was designed and engineered in Asia. Ford uses it's own name in the old 5-speed and new 6-speed which is cheaper then outsourcing. GM can’t build a transmission worth a damn so they charge the customer extra for a more dependable name brand.

Mike, you and the guys at Diesel Power should just come out and ask GM to lend you these two trucks again (and trailer) and take them somewhere closer to sea level and do the whole thing over. I'm sure GM would be up for it.

No danger that Ford will want to do anything like this. The only way they do comparisons is at their proving grounds, with their engineers, their drivers, and their hired mascot (Mike Rowe) as a witness. But of course that makes it more legit then a third party organization doing the testing.

I guess Ford will start including a footnote with every 6.7 Power Stroke diesel sold now that goes like this:

Most capable HD trucks on the planet*

*except while towing uphill, or at any elevation.

@Bryan. Face-palm. The 6.7l is built in the Fords Chihuahua Mexico plant.

Yes, we all know the original Dmax was designed by Isuzu/GM. Its isn't anymore, and hasn't been in a while.

Again, Allison makes a superior transmission, and GM knows this. Why design a new one?

Understand that Fords transmission designs are just as questionable as GMs.

GM didn't "try to beat the best"...It just happened, again.

Surely you must be hand counting all the vehicles mentioned in your OP, and you can back your claim with actual numbers.

Everyone. Thanks so much for reading this story and being so incredibly enthusiastic about each truck's performance.

Bottom line: You can't go wrong with either truck and that's a victory for both Chevy and Ford owners. The Ram HDs are great trucks too.

We've got more tests planned. Maybe even Davis Dam head-to-head. Maybe. But know this - whatever truck we test, we'll try to do the most thorough and transparent job possible. It's why we're here.

In the meantime, I've got to close this thread. It's run its course and everyone has had their say. I can't keep moderating it and work on the next story at the same time.



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