Making the move from a car to a full-size truck, like this GMC Sierra Denali, is usually perceived as a move to more of everything. More room, more power and more safety. But it also means less of some things, namely the highway agility and ease of parking that car drivers take for granted. At least it used to, until the engineers at GMC decided to even the odds.
Those ‘‘odds’’ have been evened with a handy new four-wheel steering system called Quadrasteer. And, this new take on an oft kicked around idea, has put the new 2002 GMC Sierra Denali, formerly known as the Sierra C3, on nearly equal ground with a compact car!
Engineered by parts giant Delphi Automotive, Quadrasteer works like this. Under the rear of the Sierra Denali is a steerable solid hypoid axle. A central electronic control module gathers information from front steering position and vehicle speed sensors, and feeds it to the electric motor that controls the rear axle steering mechanism.
This information enables the rear steering unit to operate in one of three phases. At low speeds, a negative phase, in which the rear wheels turn in the opposite direction of the front wheels, is in effect. This phase aids parking and tight maneuvering. At moderate speeds, the rear wheels remain straight, or in a neutral phase, just like a conventional pickup. At higher speeds, the rear wheels enter a positive phase, turning in the same direction as the front wheels. This phase improves the safety of lane changes and avoidance maneuvers. It does so by reducing the vehicle’s ‘‘yaw’’ or rotational motion. The 5 inch wider track at the rear helps too.
The driver can also manually select one of three driving modes with dash-mounted controls. Conventional two-wheel steer, four-wheel steer, as just described, or four-wheel steer/TOW mode, which changes the front to rear steering bias somewhat for easier towing.
The advantages in the Sierra Denali’s Quadrasteer are many. For one, there’s the obvious added zippiness to parking lot and other low speed chores. We can’t remember the last time we had this much fun taking a full size pickup truck through our low speed slalom. Our drivers noted there’s still plenty of front end push, and some wished the still numb steering was quicker. But the Quadrasteer system definitely accelerated the pace through the cones. Quadrasteer also reduces the Sierra Denali’s turning radius by over 20 percent. Cutting it from 46.2 to 37.4 feet, or now about the same as Saturn’s smallest sedan.
And for those who want to take advantage of the Sierra Denali’s now beefier 10,000 pound towing capacity, towing with Quadrasteer in action is like having a steerable axle mounted to the front of your trailer! And should any system failures be detected, Quadrasteer automatically reverts to two- wheel steering. But you’ll still have the added security of the Sierra Denali’s full-time all-wheel drive system which is also standard equipment on this premium pickup. And so is the ZX3 Ride Control suspension, with its two selectable modes of damping for the front and rear 46 millimeter shocks.
The Sierra Denali gets its thrust from GM’s renowned family of Vortec engines. In particular, the 6.0 liter, OHV, V8 Vortec 6000. In the Sierra Denali, this cast iron block/aluminum head powerplant generates 325 horsepower and 370 pound-feet of torque. All fed through a 4-speed automatic transmission with a tow/haul mode. At the strip, that was good for a neck-snapping run to 60 in just 7 seconds. The quarter mile passed in 15.4 seconds at 88 MPH. Our drivers noted that power seemed plentiful and bottomless, dropping off only slightly at the end of the quarter mile run. Apparently the weight penalty of the Quadrasteer’s rear axle is virtually meaningless when it comes to the Sierra’s get- up-and-go.
And the added weight at the rear certainly doesn’t hurt when it comes to braking. As the large 12 inch front, 13 inch rear discs with ABS brought the Sierra Denali down from 60 in an average 133 feet. Our drivers loved the truck’s stability and smooth pedal feel, as well as the only moderate feedback from the ABS system.
We heard mostly praises, too, about the Sierra Denali’s high level of interior comfort. As the Sierra Denali carries on the tradition of high lux premium trucking first established by its C3 predecessor. That means plenty of plush leather upholstery with power adjustable seats and heated seat bottoms and backs, and an adjustable leather-wrapped steering wheel with redundant audio controls, a programmable driver information center with premium Bose audio system with 6-disc in-dash CD changer, as well as separate audio controls for rear seat passengers. In fact, the Sierra Denali comes fully loaded.
And although pricing on the new Sierra Denali hasn’t been finalized, we don’t expect it to be a whole lot more that the $38,995 price attached to the current 2001 C3.
The story of the 2002 GMC Sierra Denali can best be summed up by saying, ‘‘Quadrasteer is here,’’ and it works! And while it’s for now only available on this top-of-the-line truck, GM promises it won’t be long before it appears on other models as well. But for now, the front seat of this powerful and plush pickup is the only place to experience this new piece of cutting edge technology. And from our vantage point, it’s a great place to be.
Engine: 6.0 Liter, Ohv, V8 Vortec 6000
Torque: 370 Lb Feet
0-60 MPH: 7 Seconds
1/4 Mile: 15.4 Seconds @ 88 MPH
60-0 MPH: 133 Feet