It's Amazing What a Difference the Right Engine Can Make

From Road & Track

This is the truck I was looking for. This is the truck I want. Not one with a 2.5-liter four-cylinder and not one with a 3.6-liter V6. When it comes to GM's midsize trucks, the diesel is the sweet spot.

I recently spent a week with the GMC Canyon diesel, and rarely have I found a better example of a good vehicle that has been transformed into a great one solely by the choice of engine. With the newly available 2.8-liter Duramax turbo-diesel, the GMC is the midsize truck many of us have been hoping for.

Note that while I haven't had the chance to test drive the Canyon's Chevrolet twin, the Colorado, it shares the same mechanicals. So I'd expect the same happy result.

Engine choice has always been important, but these days there are few that outright suck. Many are just fine. Like so-so, meh-to-middling, I-can-live-with-it fine. But often there's another engine choice offered on the same vehicle that makes it fabulous. So it's a shame if you buy a car and get stuck with the former.

Notably, the more expensive option is not always the better choice. Cadillac's 2.0-liter turbo four-cylinder, for instance, is my pick over the aging, naturally aspirated 3.6-liter V6. Both are available on the new CT6. The turbo is less expensive and delivers more torque lower in the rev range, which gives a readier response in a significantly less nose-heavy package.

The best way to avoid the wrong powerplant? Test drive all of the options. I'm amazed how many people are loathe to actually test drive their prospective buys at a dealership. So if you're doing it anyhow, try out every engine. Go ahead and dedicate the extra 30 minutes per powerplant and annoy the salesperson. Because the difference in something like the oil-burning Canyon and its gasoline brothers is a big one-and may well impact how much you do or don't love your shiny new automobile.

Perhaps your truck needs are similar to mine. You don't tow stuff, but you do need to haul wood and rocks and garbage cans, and you're likely to use your truck every day to commute or run errands. You want to be able to fit the damn thing in your garage. So a midsize is the right size for you.

But your first thought probably wouldn't be diesel. "A lot of people probably never considered one before," says Anita Burke, the chief engineer of GM midsize trucks. "But since its release four months ago, the order rate for the diesel has been very strong. People get in and drive them and they love them. You don't feel the bumps and bumps of the old diesels. This is not the diesel of old."

Burke says the company opted to wait for the second year to release the diesel to give themselves ample time to make sure everything was right. The company says that the Duramax is the cleanest truck diesel that it has every released. Like many new diesels, it uses urea to scrub nitrogen oxide from the exhaust, and GM recommends refilling the tank when you change the oil.

The engine that I thought I'd most enjoy in the Canyon, the 305-horsepower V6, just wasn't as smooth, responsive, or lovely as I'd envisioned. Torque isn't impressive at 269 lb-ft, and the six-speed automatic too often is on the hunt for a happy gear. And while the 2.5-liter four-cylinder seems like a progressive idea, its 200 hp and 191 lb-ft of torque lacks the real-world punch you want to live with. (At least the smaller engine is available with a six-speed manual.)

Compare those numbers with the livability of the turbo-diesel's 181 hp at 3400 rpm and 369 lb-ft of torque at 2000 rpm. That's 100 more lb-ft of torque than the V6, which doesn't reach its 269 lb-ft peak until 4000 rpm. And the diesel is even within spitting distance of the Chevy Silverado's 5.3-liter V8, which makes 383 lb-ft.

GM's aim was to create a diesel that produced none of the uncomfortable rumble or tremors common to the powerplant, and engineers were almost German in their over-engineering. Burke says that a "centrifugal pendulum vibration absorber" was designed into the transfer case, basically a mechanical damper that evens out the irregularities that transmit into the truck. All Canyons and Colorados come with hydraulic engine mounts, which help, and the diesel models get additional acoustic materials with more density.

It all results in a truck that is rewarding to both drive and ride in. No rough idle or uncomfortable shudders transmitting into your bone marrow. The engine lends a constant thrum of competent power, sweeping the truck up highway ramps and ably allowing merges into fast traffic. It also scoots around mountain roads. Big hills are no problem, and it's always fun to look down and watch the rpms steadfastly stick below 3000. You sweet, refined oil-burner, you.

And this time, GM's six-speed transmission doesn't need to do much at all. It's like the Maytag repairman in the commercial, just kinda hanging in the background looking for something to do.

The diesel is a $3730 option, and it only comes as a crew cab. And yes, diesel is more costly, but I still don't care. It makes 22 city, 31 highway, versus 18/26 for the two-wheel-drive V6. The four-cylinder, meanwhile, only manages 20/27 for the rear-wheel.

"Most midsize drivers use their vehicle every day, and the diesel's range is phenomenal," Burke says. "It really fits a lot of people who want that fuel economy and the low-end torque in a really drivable form. It makes my heart sing."

One expects the chief engineer to cry her vehicle's praises. But in this case, I don't disagree. The diesel Canyon left my heart feeling pretty glad, too.

Jason Harper, a contributing editor to Road & Track, has tested and written on cars for two decades. His scariest drive was a rally race in an original Lancia 037, his first drive of a supercar was the Porsche Carrera GT, and the only time he's gotten a speeding ticket was in a base Mini Cooper. His column, Harper's Bizarre, runs every Wednesday.