First Test: 2007 Chevrolet Tahoe LTZ
Priming the Pump: Running almost on empty, GM digs deep with its new full-size truck platform--and strikes it big
It was 24 short months ago when GM pulled the GMT900's production schedule forward almost six months for a January 1, 2006 on-sale date. Most companies delay introductions due to unforeseen plant problems or technical difficulties; the reverse is often risky. Beyond showing confidence in the team that put these trucks together, it reveals that GM is pinning hope on the new platform that spawns the Tahoe and Suburban, along with GMC and Cadillac variants. Can a single SUV architecture save a company's profits at a time when its most viable segment is shrinking?
A first-drive smack-down test on the track and in the field reveals that GM brought game.
The old Tahoe was about as aerodynamic as a brick, so major work went into this area. There's a noticeable change in proportions: The windshield glass has more slope, the front end is reshaped, and the grille and bumper now work as a single aero-designed unit with few panel gaps. Likewise, changing the rear-end aero, smoothing out the mirrors, and lowering the airdam improved the overall drag of the full-size SUV by almost 12 percent--that means increased fuel economy. But fuel ratings have been bettered in other important ways, too.
GM is touting its Gen-IV 5.3-liter V-8 small-block as the most fuel-efficient engine in its class, with unadjusted combined-average fuel-economy ratings in two- and four-wheel drive above 20 mpg, due in large part to Displacement On Demand, the high-tech cylinder shutoff system. Move your foot on and off the throttle and watch the information display center, which indicates V-4 or V-8 mode. In addition to DOD, the new 5.3-liter engines (an all-aluminum version for 2WD models and a cast-iron block version for 4WD models, able to run E85 fuel) give the Tahoe more horsepower than any other vehicle in its class. However, both have less torque compared with Ford's 24-valve Expedition and Nissan's 32-valve Armada.
Look for the 4.8-liter GM small-block V-8 to become an option midyear 2006, with the possibility of a Tahoe SS version using the 400-horse, 6.2-liter V-8 that'll also power the new Escalade.
Around town, our 4WD cast-iron 5.3-liter V-8 proved more than adequate for moving through traffic and passing slowpokes. The electronic throttle ramps in power smoothly, while the four-speed transmission is quick to downshift, making energetic test loops along the Angeles Crest Highway exceptionally fun: Reeling in the cars ahead, passing when safe. At the track, our test unit ran 0-to-60 mph in 8.6 seconds (0.2 second faster than the last Tahoe we tested), with a run down the quarter mile in 16.6 seconds at 82.9 mph--slightly slower than the previous, nearly 500-pound-lighter Tahoe.
The new frame--49 percent stiffer due to newly hydroformed front and rear sections--is widened by three inches in the front, an inch in the back. This, along with an all-new front suspension (goodbye, torsion bars; hello, coils) and rack-and-pinion steering, allowed suspension engineers to improve ride and handling characteristics. The steering has a soft spot on center, but then provides more progressive feedback as cornering forces build.
The Tahoe's rear five-link/live-axle suspension also has been retuned with new bushings and shock valving. Standard on LTZ models is a new Autoride shock setup, which can adjust in real time to modify stiffness for a smoother ride on well-paved straight-line highways, as well as provide a firmer setting for lively cornering or when carrying heavy loads. For additional style, GM offers 20-inch polished-aluminum rims, and, to offset added weight, GMT900 SUVs have aluminum lower control arms. All Tahoe models use a four-channel, four-sensor traction-control system that includes a rollover mitigation component, designed to thwart a tip-up situation.
The Tahoe's suspension, steering, and frame improvements translate into better slalom numbers. While the prior Chevy darted through the cones at 56.8 mph, the 2007 model finished at 57.2 mph. During slalom testing, with stability control turned off, the new software algorithms proved much less intrusive than in previous systems--StabiliTrak actually stayed off when it was shut off.
The technological advances are compelling--but the Tahoe's most critical changes are to the interior. Cabin materials are significantly improved, with softer surfaces and tighter gaps and tolerances on all panels, the center stack, and gauges. The gauges have a more upscale look with LED backlighting and chrome details that highlight but don't overpower. The dash panel is now moved forward and down almost six inches, increasing real and perceived room and visibility.
Front passengers are protected by dual-stage airbags, available roof-mounted head-curtain airbags for rollover protection, seatbelt pretensioners, and enhanced body protection. StabiliTrak is standard, OnStar is standard for one year, and GM expects the Tahoe to get five-star ratings when government crash tests are completed. GM calls this strategy a "360-degree safety perimeter."
It's just not enough to get to the party on time anymore--you have to get there ahead of schedule and with more goodies than anyone else. To that challenge, the new Tahoe delivers. The platform will be available in two wheelbases, 116 and 130 inch; the shorter version will be released first as the Tahoe--the core model as well as the highest-volume sibling. The other GMT900-based models, including the Suburban, will be phased in over the next 12 to 18 months.
So it's encouraging that GM can create a vehicle line that moves to the head of its class right out of the gate instead of just blending in with existing offerings, only to be trumped when the other team comes out with something newer.
Has GM hit a gusher? Probably too soon to say, but the Tahoe is exactly what GM needed--a bigger, stronger, safer, more fuel-efficient sport/utility with a clean interior--finally. Next up? Another high-profit, high-volume, but risk-filled segment: full-size pickups. GM knows the drill.
|2007 Chevrolet Tahoe LTZ|
|Drivetrain layout||Front engine, 4WD|
|Engine type||90° V-8, iron blk/alum heads|
|Valvetrain||OHV, 2 valves/cyl|
|Displacement||325.0 cu in / 5328cc|
|Power (SAE net)||320 hp @ 5300 rpm|
|Torque (SAE net)||340 lb-ft @ 4200 rpm|
|Weight to power||18.3 lb/hp|
|Axle/final/low ratios||4.10:1:1 / 2.87:1 / 2.72:1|
|Suspension, front; rear||Control arms, coil springs, anti-roll bar; live axle, coil springs, load-leveling shocks, anti-roll bar|
|Brakes, f;r||13.0-in vented disc; 13.5-in disc, ABS|
|Wheels||20 x 8.5-in cast aluminum|
|Tires||275/55R20 111S M+S Bridgestone Dueler H/L Alenza|
|Track, f/r||68.2 / 67.0 in|
|Length x width x height||202.0 x 79.0 x 77.0 in|
|Ground clearance||9.0 in|
|Apprch/depart angle||17 / 22 degrees|
|Turning circle||39.0 ft|
|Curb weight||5840 lb|
|Weight dist, f/r||52 / 48 %|
|Towing capacity||7700 lb|
|Headroom, f/m/r||40.3 / 38.5 / 38.2 in|
|Legroom, f/m/r||41.3 / 39.0 / 25.4 in|
|Shoulder room, f/m/r||65.3 / 65.3 / 61.7 in|
|Cargo Vol behind f/m/r||108.9 / 60.3 / 16.9 cu ft|
Acceleration to mph
|Passing, 45-65 mph||4.5 sec|
|Quarter mile||16.6 sec @ 82.9 mph|
|Braking, 60-0 mph||133 ft|
|600-ft slalom||57.2 mph avg|
|Lateral acceleration||0.72 g avg|
|MT figure eight||29.9 sec @ 0.53 g avg|
|Top-gear revs @ 60 mph||1900 rpm|
|Base price||$37,000 (mfr est)|
|Price as tested||$48,000 (mfr est)|
|Airbags||Dual front, front side, f/m/r curtain|
|Basic warranty||3 yrs / 36,000 miles|
|Powertrain warranty||3 yrs / 36,000 miles|
|Roadside assistance||3 yrs / 36,000 miles|
|Fuel capacity||26.0 gal|
|EPA city/hwy econ||15 / 21 mpg|
|MT fuel econ||14.2 mpg|
|Recommended fuel||Regular unleaded|