2008 GMC Sierra 1500 Performance
Despite having very good power and handling and numerous engine and suspension options, the 2008 GMC Sierra falls toward the middle of the class for its performance. Nevertheless, Kelley Blue Book reports, "Sufficient power and surprising ride comfort are two hallmarks of the GMC Sierra."
In a performance-based comparison test, Car and Driver found that, "GM's new baby matched the Nissan (full-size Titan) in steering precision, transitional grace and engine smoothness. Indeed, both on the road and on the course, the GM trucks garnered unanimous praise."
Acceleration and Power
When referring to the Sierra 1500's power, reviewers unanimously agree that the Sierra is a success. In fact, Consumer Guide reports that "acceleration is more than adequate at all speeds." adds, "While driving up a steep hill, out of curiosity, I floored the accelerator pedal and was amazed at how quickly it picked up speed." While the says, "Acceleration is good, meaning that the GMC Sierra 1500 has no problems entering freeways or changing lanes."
All this praise can be accredited to the GMC Sierra 1500's wide variety of engine platforms, all of which were found to provide sufficient power. The base-engine is a Vortec 4.3-liter V6, which makes 195 horsepower and 260 pound feet of torque. The next engine level is a Vortec 4.8 liter V8, which generates 295 horsepower and 305 pound-feet of torque. Kelley Blue Book writes "The 4.3-liter V6 and 4.8-liter V8 should be more than adequate in work truck applications." And when reviewing the standard cab version with the base model 4.8-liter V8 engine, MarketWatch states, "With a zero-to-60 time of just over eight seconds, the GMC is in line with its rivals."
The next powerplant upgrade is the buyer's choice of a selection of three different 5.3- liter V8s, all of which produce 315 horsepower and 338 pound-feet of torque. two of the three are available as either an iron or aluminum block; the iron block allows for great towing and hauling capacities because it can withstand the greater heat associated with extreme use. For the environmentally conscience driver, GMC offers a FlexFuel version of the 5.3-liter V8, which can run full-time on E85. Kelley Blue Book reports "For dual-use work and pleasure driving we recommend stepping up to at least the 5.3-liter V8 engines."
At the top end of the 1500's engine options is the Vortec 6.0-liter V8 (only available on the Crew Cab or Extended Cab), which makes 367 horsepower and 375 pound-feet of torque. Car and Driver reports, "Not surprisingly, acceleration was particularly impressive with the top-grade 6.0-liter V-8."
The 5.3-liter and 6.0-liter V8s also come standard with GM's Active Fuel Management System, which strikes a balance between necessary power and desired fuel efficiency. Active Fuel Management technology only uses four cylinders in less demanding driving conditions while seamlessly engaging all eight cylinders when necessary. The driver information center on the dash shows whether you are in four- or eight-cylinder mode; yet, theand others would prefer a "light in the instrument panel flash on when in 4-cylinder mode so you wouldn't have to take your eyes off the road to see you are conserving fuel." Regardless of the display format, the stated, "The upshot is a full-size, four-wheel-drive truck that can complete a 400-mile round-trip journey, including several side-road diversions, with 120 miles worth of regular unleaded gasoline left in its 26-gallon tank."
The Environmental Protection Agency (EPA) estimates that the V6 gets 15 miles per gallon (mpg) in the city and 20 on the highway, while the 4.8-liter V8 gets 14 mpg in the city and 19 on the highway. The 5.3-liter V8 gets 15 mpg in the city and 20 on the highway, while the Flexfuel version of that engine gets 14 mpg in the city and 20 on the highway when using gasoline, and 11 mpg in the city and 15 on the highway when using E85. The 6.0-liter V8 gets 13 mpg in the city and 18 on the highway.
All Sierra engines are mated to a four-speed automatic transmission. While the great majority of reviewers were just as impressed with the Sierra's transmission as they were with its powerful range of engines, some had their reservations. Consumer Guide reports the "smooth-shifting transmission kicks down quickly for more passing power," but the writes, "The four-speed automatic transmission should be replaced by a more fuel-efficient five-speed or six-speed model."
Handling and Braking
Test drivers seem generally pleased with the 2008 GMC Sierra 1500's handling abilities. In fact Kelley Blue Book reports, "The big pickup truck is surprisingly nimble and easy to maneuver." Car and Driver adds that they found the Sierra "smooth and quiet on the highway." However, one should not seek a car-like ride from the Sierra. The great majority of reviewers have found that the vehicle handles like a truck; yet, is not as stiff as previous generations. Though this is an improvement, it is in no way comparable to a sedan. The says that the Sierra "is a full-size pickup truck that rides and handles like a pickup truck. People desiring something gentle and sedan-like should shop elsewhere." Still, adds, "It took only a few miles to realize the expression "rides like a truck" has taken on a new meaning, but it's not a back-buster. Sierra was comfortable and would be a pleasure for long-distance motoring."
The Sierra's smooth-for-a-truck ride is the result of an all new hydro-formed, fully boxed chassis with additional cross-members and upgraded suspension components, which replaced the front torsion bars with coil-over shock absorbers and the recirculating-ball steering with a lighter, simpler and more precise rack-and-pinion system. Consumer Guide describes the steering system as "nicely weighted". MarketWatch adds, "The new rack and pinion steering enhanced our confidence on the back roads where handling was better than we would expect from such a heavy truck." The new suspension system also incorporates a rear-axle design that mounts the shock absorbers more upright for better control.
Different suspension options are available, and each is tuned for different performance strengths. The Z60 is tuned for best street performance, while the Z71 has a specialized suspension for off-roading. The smoothest ride is offered by the Z83 suspension. The Z85 and NHT suspensions offer enhanced towing capabilities. Consumer Guide describes the Z60 as making the ride "more jittery", thanks to its lowered stance and large wheels, and they also describe the Z71 as exhibiting "some choppiness over pavement cracks", and the Z85 as having "noticeable body lean in fast turns." Cars.com adds, "Of the suspensions, the Z83 offers the smoothest ride while the Z85 is slightly stiffer."
Most reviewers were enthused by the feel and performance of the brakes. New Car Test Drive reports, "One of the trucks we drove had its bed loaded with heavy cargo and the brakes were good enough that nothing dramatic happened when we had to make a hard and fast stop." The Sierra can tow a trailer weighing up to 10,500 pounds and a payload capacity of up to 2,160 pounds, depending on the truck's configuration.