ROAD TEST | Denali Diesel’s Big Boys Are Only Good If They Work Out Every Day

DALLAS – More than two years later, I was finally on my way to a privileged diversion, the Dallas Auto Show.

Yes, I like to look at pretty and shiny things.

COVID has changed so much. New cars cost over $45,000, used cars over $30,000, and people wait weeks for them. The conclave of cars and vans at the Griffin Street Convention Center in downtown Dallas is now called the North Texas Auto Show, and a third of the cavernous room was empty, the space filled with mini drives in a handful of electric vehicles that looked lovely but far from ready to conquer the planet.

One thing remained the same, my luck. It was one of the weeks where I didn’t know what I was driving until I looked out the dining room window – much like a child on Christmas morning – to see what car the fairies had. delivered.

Two days before my trip to Big D, a ginormous shiny black over $70,000 diesel-sucking pickup, a 2021 GMC Sierra HD Denali 2500, dropped into my driveway like the Pillsbury Dough Boy trying to fit into a Little Ducky inner tube.

Powered by a 6.6L Duramax V-8 turbo-diesel bolted to an industrial-grade 10-speed Allison automatic, this beast develops 445 hp, 910 lb-ft of torque and can drag 18,510 lbs. behind.

Shit, and I left my cruiser in my other garage.

As prodigious as these numbers may seem, the most important, from my point of view, was this number: $5,094. That was the price of a single gallon of diesel fuel in Texarkana the day I left for Dallas.

A quick run showed Black Behemoth had 12.2 mpg in the city. I dug a little deeper into the onboard fuel monitor and found it had averaged 15.5 mpg over the previous 1,657 miles. It would have to do better than that if we were to go 370 miles round trip and then spend the remaining five days of the week.

Filling a 36 gallon fuel tank at $5 per person was NOT on Dad’s agenda. It’s enough that he had to take the day off, eat on the road and pay for a hotel. (The Sova, one of those micro-hotels, is a quiet, clean place if one’s comfortable sleeping in a walk-in closet. Price: $112, plus $12 parking.) Sigh — we guess that there are more expensive hobbies.

On the way there and back, I tried something drastic. I drove below the speed limit. Stop screaming. The world is not coming to an end. It just stopped, well, spinning, for a day or two. There’s no doubt that the concept of your true 73 in a 75 had a negative cosmic pull and probably delayed spring by about a week, but we all seem to have survived.

The net effect was that fuel economy improved to 16.8 mpg – an 8.4% increase – and I was able to drive to and from Dallas, drive home, do groceries, going to work and even doing a weekend at the lake, and that little amber fuel light didn’t come on until the morning the nice guy came to pick up his big truck.

Of course, it cost General Motors $180 to bring it back to Dallas. Also, DEF, that expensive liquid that has to go into diesel tanks every few tanks, was getting low.

To be honest, that little voice in the back of my head keeps telling me that I should have driven my hybrid Highlander at big D. Not only would it have achieved twice the fuel economy, but at my expense, but diesel engines also emit 25 to 400 times more mass of black carbon particles and assorted organics per mile; so that was a lot of pollution to dump into the atmosphere just for the privilege of sitting high and acting like I was someone important.

Pretty cool

This brings me to the only relevant point that I am likely to make today. These rugged pickups only make sense if you’re towing something huge on a daily and weekly basis, and not just because they’re bouncy and uncomfortable without something heavy in the back. Today’s quarter-ton pickups have plenty of towing power and much better fuel economy.

GMC’s Duramax diesel will tow 18,500 pounds. Ford’s F-2550 diesel will haul 22,800 pounds. and Ram’s 6.7L Cummins® Turbo-Diesel will haul 20,000. Those are big numbers. A four-horse trailer, on the other hand, weighs between 4,200 and 8,400 pounds. Add four horsepower up to 660 lbs. by, and the weight is still less than the capacity of a competent quarter-ton truck.

Surprisingly, GM’s 3.0L Duramax only pulls 9,500 pounds, but Ford and Ram both offer quarter-ton diesels that haul over 12,500 pounds. Ford will give you around 27 mpg and Ram over 30 mpg.

Motor Trend has a nice cover of these issues. I’ve pored over payload and towing capacity charts for over four decades and this year I found the biggest surprise yet. Ford and Toyota manage to drag over 12,000 pounds. mating hybrid systems to twin-turbo V-6 configurations. My friend Tim Esterdahl, a pickup truck expert, is of the opinion that the new Tundra has the best fuel economy of any light-duty pickup ever.

Beyond that, the GMC Denali still leaves a lot to be desired. Although it has tons of cool features, including a camera system that finally rivals Ford’s, the interior still has a cheap, plasticky feel. Still, it has tons of storage slots, cubbies, cup holders, and power outlets. Pickup truck drivers, who tend to favor practicality and versatility over aesthetics, will find what they’re looking for.

An available 8-inch infotainment screen is remarkably smaller than the 12-inch screens that have been available on Ram for two years.

In addition, important elements of driver assistance technology are not available. I understand that van drivers tend to be conservative so demand probably isn’t high, but a truck’s ability to stay in its lane and a safe distance behind vehicles ahead seem more important when we drag 10 tons from the stern.

Who buys a $70,000 vehicle? Financial advisers say that an automobile purchase should not represent more than 35% of gross income. Let’s see… 0.35X = $70,000. Divide both sides by 0.35. Oh, that’s $200,000 a year, right? Less than 7% of the American public does this.

You would think that the top 7% would be more demanding.

Test Drive is a self-review column written by Bill Owney.


2020 GMC Sierra HD Denali (Photo courtesy of General Motor Co.)



Maria D. Ervin