For the first time, GM has put the Denali trim level in their Sierra truck. In this particular instance, it also happens to be a 2500-series Heavy Duty Crew Cab with a standard 6’6’’ box and the new 6.6-litre Duramax diesel.
Translated into everyday language, this truck is big enough to need the chrome tubular running boards to make getting in and out easy. It also means that the most luxurious truck this side of an Escalade has a towing capacity of 9,843 kg (21,700 lbs).
Denali-equipped vehicles have a couple of distinctive traits on the outside that will let you know what you are looking at. Up front is a distinctive four-bar grille, and along with that, the bumpers are body-coloured while the door handles are chromed. An added feature is that the wheel rims (18- or 20-inch on the 2500) are chromed as well.
Roughing it in luxury
Inside, the Sierra Denali has just about everything you need as standard equipment. Very comfortable, power-adjustable, leather-covered bucket seats with multi-level heaters are standard for both driver and passenger. The 60/40 flip-up rear seat is equally comfortable, with as much foot room and knee room as those in the front enjoy.
Instrumentation is highly visible and complete, with trip computer readouts in the bottom portion of the instrument cluster. Things like power-adjustable pedals are standard, as is a new, built-in electronic trailer brake and trailer sway control. The steering column-mounted shift lever has the new “smart brake” (which is an exhaust brake) control mounted on it.
Woodgrain trim, a large centre console, rear-seat climate control, XM radio and navigation are the start of the modern electronic comfort age. Add in Bluetooth wireless connectivity as well as a USB port with iPod integration, and you will be able to have any tune you want to listen to at your fingertips. To make sure the sound comes out properly, GM uses a top-of-the-line stereo which has more speakers than I could find!
The 6.6-litre Duramax now uses Piezo injectors running at 2,000 bar or 30,000 psi to have better control of the injection moment and improve fuel economy. In addition, changes to the intake exhaust and block make the engine quieter, run better and improve performance. On the emissions side, these changes have reduced NOx emissions by 63% over last year.
Exhaust gas regeneration has been a contentious subject due to the frequency of regeneration and the detrimental effect it had on fuel economy. GM reports that the new system has improved by 75%, now running once every 1,100 km or so. DEF or Diesel Exhaust Fluid (a urea-based formulation) will now last about 8,000 km before needing to be topped up.
Changes to the frame have stiffened the front by about 25%, allowing any Sierra model to be equipped with a snow plow. In addition, changes to everything from control arms to the urethane bushings in the front end provide an improved, positive steering feel at all speeds.
Changes to the rear include larger asymmetrical leaf springs and a two-stage design (three on the 3500), which improves ride quality at various levels of load capacity while increasing that load capacity by up to 14% (depending on what you order).
When you redesign the engine and improve its power, you need to redesign the transmission, and the Allison 1000 is no exception. First on the list was an improved “spin loss” rating where improvements in fuel economy and power transmission come from getting more power to the drive wheels.
The horsepower and torque capacities had to be improved to handle the new 6.6 Duramax’s output. Other electronic wizardry has improved 0 to 100 km/h and quarter-mile times by 0.3 and 0.9 seconds respectively. For a truck of this size, those are huge improvements.
Driving Finesse
With all this power under foot, GM has chosen to use a long throttle tip-in so that customers that stab the throttle don’t head for orbit or worse yet, tear the tires off when pulling a heavy load. With a 10,000-lb load on behind, it is possible to spin the tires if you do something foolish like floor it when coming off a standing start. Sometimes, the tires even chirp when the transmission goes into second gear.
Using the Denali 2500 in town on a regular basis requires patience that most car drivers will never know. It takes a level of finesse that most car owners will never achieve just to parallel park, if it will even fit in the space. Angle parking is a bit easier, but get used to the last metre or so sticking out of the space.
On the road, rest assured that you can feel the potholes in our streets, but for the most part, they are of no concern. In town, you have great visibility and can plan your moves well in advance, while having the power to make those moves as long as you remember to put the throttle down far enough!
The Sierra 2500HD Denali starts at $59,345, and our tester, including the diesel powertrain and other options, is priced at just under $75,000.
In the world of political correctness, the Denali 6.6 Duramax can also run on 20% biodiesel, so do the politically-correct thing and put this truck on your shopping list.
Review and Photo By Charles Renny
Auto123
