First Look: 2008 Chevrolet Tahoe Hybrid 2 Mode

Changing the Rules Never Looked so Easy

Mark Williams
Nov 26, 2007
Photographers: The Manufacturer
In the automotive world, the term "hybrid" didn't even exist 10 years ago. Now, it's practically defined by the success of Toyota's homely Prius. From Leonardo DiCaprio to John Q. Public, driving a hybrid has come to show that you care about the environment--maybe more than other people do. But there's one more thing it says about its buyers: They're perfectly happy compromising on all of their towing and hauling needs (and we can't remember the last time we've seen more than two people in a Prius). Enter GM. As if to squelch the voices of SUV-haters, GM brought out its long-awaited two-mode hybrid system in the full-size Chevy Tahoe (and GMC Yukon; see sidebar) and this could be the game changer.
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First seen in huge diesel/electric buses, the system was produced in partnership with BMW and DaimlerChrysler (now The New Chrysler). The Tahoe's version of the system is reported to improve city-driving fuel economy by as much as 40 percent and highway driving up to 25 over a comparably equipped 5.3de and out; and they've carefully integrated all the systems to work together.
When listening to GM Hybrid leaders tell their story, you get the sense every excruciating detail was discussed and deliberated. "This is a strategy we've had in place for quite some time. We've always had the means to make a one-off specialty vehicle, but we wanted a bigger footprint, something that could make a huge impact," says Mary Sipes, vehicle line director, Full-size Truck Group. "That's why we started with the GMT900 platform--we wanted to get big numbers on a big-volume product."
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With the GM bigwigs in town with a new Chevy Tahoe Hybrid 2 Mode, the first here on the West Coast, we went for an entirely too short drive around Southern California. To fully test this vehicle's claims, GM engineers and I drove through the jammed side streets of Santa Monica, Los Angeles, and Beverly Hills in the heart of early-morning rush hour.
The Hybrid looks sportier than a regular Tahoe, thanks in large part to the lowered stance and larger, color-matched front bumper and air dam. The front end has been reworked to eliminate drag-causing bumper gaps, tow-hook holes, or rough seams. The key is to move oncoming air around the vehicle as quickly and smoothly as possible. Even the sidesteps are aerodynamically tucked behind the front tires and under the door panels. Beyond that, the only visual giveaways on the outside are a small set of side- and tailgate-mounted "Hybrid 2 Mode" badges. Behind the wheel, the interior dash is almost identical to the conventional full-size SUV, with the exception of a small "economy" gauge on the dash. On the nav screen, an easily accessible animated screen charts power flow and direction.
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As we started our cruise, I monitored flow from the battery packs to the driveline to the rear wheels. The only detectable sound came from the rear as a small fan cooled the battery pack under the second-row seats. Electric drive took the SUV to about 20 mph, but there was a slight vibration in the seats as the icon on the information screen showed the 6.0eter indicated the engine had shut off, and the regenerative brakes were channeling power back into the battery packs. The ride itself felt rough, as if the shocks were a tad too stiff. No doubt the low-rolling-resistance tires have something to do with that as well. And it wouldn't surprise us if the tire pressures were up.
Overall, the system drives like that of a Toyota Prius, but seems to lack the style, function, or power trade-offs. The Tahoe looks normal, hauls like a Tahoe should, and when you want to flatfoot it to pass someone, you get all 320 horses from the all-aluminum 6.0uel economy," says Mark Cieslak, assistant chief engineer for Chevy Tahoe Hybrid, from the passenger seat.
Watching the gauges to see what kind of fuel economy we could get became something of a game as we navigated the clogged arteries of Westwood near UCLA. Much of the time the engine was either in full electric mode or V
The heart of the system, inside the conventionally shaped transmission bellhousing, consists of two electric motors and four stationary gearsets that distribute the flow of power. The engine and motors transfer torque to a series of gears in the transmission back and forth between two modes so smoothly it's impossible to detect any shifting. A 300V), and a special converter produces 12e're told the transmission is so smart and strong there wasn't any need to include a pushbutton Tow/Haul mode. That remains to be seen. We didn't get much highway driving time, either, but the fact that the Tahoe has 3.08:1 gears, a more aggressive V
It looks like GM's going to be cautious with the rollout, making only a small number of the Hybrid 2 Modes in its Arlington, Texas, plant, as GM carefully gauges demand. Chevy and GMC will get the hybrids first, but expect Cadillac and Hummer to be close behind. Although prices haven't been released yet, we can't imagine Chevy or GMC will let the Hybrid 2 Mode be the most expensive model in their respective lineups. The Chevy should cost around $40,000 and the GMC $45,000. It makes sense that a game-changer should be somewhat affordable, especially one that allows you to carry seven people and haul a 6000
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How GM Engineers Reduced Mass
• All-aluminum hood and liftgate
• Aluminum front and rear bumper beams
• Most of the driveshaft made of aluminum
• Almost 10 pounds removed from each seat; (however, third-row option still identical to all other full-size GM SUVs)
• Much smaller, lighter 12-volt battery
• New aluminum wheels on all hybrids
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GMC Yukon Hybrid
The Chevy Tahoe 2 Mode will be sold only in midlevel trim, but the GMC Yukon Hybrid 2 Mode will offer a higher trim-level package, yet its price is said to fall well below the Yukon Denali option package. Chevy pricing will be about $40,000, with the GMC equivalent able to garner around $45,000. Some reports have GM willing to take a $7000 hit for the first year or two before it can get a tighter handle on specialty manufacturing costs. For now, only one plant is producing the variants, but the system is flexible enough to spread to other full- or midsize SUV and truck plants when needed.
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Remember the Pickup Hybrid?
Astute truck aficionados know this isn't GM's first foray into hybridland. In fact, just last year (as a 2007 model), Chevy and GMC offered a hybrid truck as a contractor's special. The word "hybrid" confused some because the Parallel Hybrid Silverado and Sierra never ran on electric power but did have an electric starter generator and an engine shutoff mode. Reportedly providing an eight- to 10-percent fuel benefit and four 110d never caught on, and GM has since frozen the pickup version. As you might imagine, the new 2 Mode system seems tailormade for a much better, more practical pickup application--if GM builds a Hybrid 2 Mode pickup, it could arrive for the 2010 model year.
What's Inside and Underneath?
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01: •6.0-liter V-8 uses current-gen V-4 and V-8 management system
02: •Because 100 percent of torque's available at zero rpm, Hybrid uses 3.08:1 gears
03: •300-volt energy storage system housed under second-row seats
04: •Two electric motors and four fixed gears inside a regular trans housing
05: •Brake system uses regenerative and hydraulic technology
06: •Specially designed harder-compound tires for low rolling resistance
07: •First full-size SUV with electric power steering

2008 Chevrolet Tahoe Hybrid 2 Mode
General
Location of final assembly Arlington, Texas
Body style 4-door, 8-pass SUV
EPA size class Special purpose
Drivetrain layout Front engine, 4WD
Airbags Dual front, side, curtain
Powertrain
Engine type 90° V-8, alum block/heads
Bore x stroke, in 4.00 x 3.62
Displacement, ci/L 364/6.0
Compression ratio 10.8:1
Valve gear OHV, 2 valves/cyl, VVT
Fuel induction AFM SFI
SAE horsepower, hp @ rpm320 @ 5200
SAE torque, lb-ft @ rpm 360 @ 4000
Transmission 2 Mode continuous electric ratio/4 fixed spds
1st 3.69:1
2nd 1.70:1
3rd 1.00:1
4th 0.73:1
Reverse Infinite to 1.70:1
Axle ratio 3.08:1
Transfer-case model MP 3023
Low-range ratio 2.68:1
Crawl ratio (1st x axle gears x low range) 30.9:1
Recommended fuel Regular unleaded
Dimensions/Capacities
Wheelbase, in 116.0
Length, in 202.0
Width, in 79.0
Height, in 75.0
Track, f/r, in 68.2/67.0
Headroom, f/m/r, in 41.1/38.5/38.2
Legroom, f/m/r, in 41.3/39.0/25.4
Shoulder room, f/m/r, in 65.3/65.3/61.7
Hiproom, f/m/r, in 64.4/60.6/49.1
Cargo vol behind 1st/2nd/3rd row, cu ft 108.9/60.3/16.9
Ground clearance, in 7.5
Approach/departure angle, deg 13.8/19.9
Base curb weight, lb 5870
Weight distribution, f/r, % 54.0/46.0
Max payload capacity, lb 1500
GVWR, lb 7300
GCWR, lb 13,000
Max towing capacity, lb 6000
Fuel capacity, gal 24.5
Chassis
Construction Ladder frame
Suspension, front/rear Independent, double A-arm, coilover/ live axle, coil springs, anti-roll bar
Steering type 42-volt electric
Turns, lock to lock 3.4
Turning circle, ft 39.4
Brakes, front/rear 13.0-in vented disc/13.5-in vented disc, 4WABS
Wheels 18x7.0-in aluminum alloy
Tires P265/65R18 Bridgestone Dueler H/T
Load/speed rating 112S
Performance
Acceleration, 0-60, sec 8.0 (TT est)
Braking, 60-0, ft 130 (TT est)
EPA fuel economy, city/hwy, mpg N/A
As-tested fuel economy, mpg (city only) 17.6
Price
Base price $35,000 (est)
Price as tested $40,000 (est)

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Chevrolet Tahoe

Fair Market Price
$43,383
Editors' Overall Rating
Basic Specifications
MSRP: $46,300
Mileage: 16 / 23
Engine: 5.3L V8
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