2008 Chevrolet Tahoe HybridPosted on July 25th, 2008
Full-sized sport-utility vehicle gets a green connection
By Nina Russin
Can a full-sized sport-utility vehicle achieve the same fuel economy as a mid-sized passenger car? The new Chevrolet Tahoe Hybrid can: average fuel economy for the two-wheel drive model is 21 miles-per-gallon.
A gasoline/electric powertrain developed jointly by General Motors, Chrysler and BMW has more horsepower than the 4.8-liter and 5.3-liter V-8 engines available in other Tahoe models.
Since electric motors develop peak torque at extremely low engine speeds, the hybrid has exceptional low-end power. The Tahoe Hybrid tows up to 6000 pounds.
The V-8 gasoline engine runs on 87 octane fuel. A nickel-metal-hydride battery pack supplies power to the electric motors.
The battery pack recharges on the go using regenerative braking. Batteries are located under the second-row seat: the pack doesn’t interfere with tumble-and-fold seat configurations.
Two mode system
Engineers use two strategies to maximize fuel economy. Electric motors run the truck’s accessories when the gas engine shuts off at idle, and boost engine power when the vehicle is moving. A cylinder shut-off system cuts power to half the engine cylinders when power demands are low, so the six-liter V8 has the fuel economy of a four-cylinder.
The transmission operates in continuously variable mode to maximize fuel economy during normal driving. It also has four fixed gear ratios, to enhance engine power when the truck is accelerating hard or towing a trailer.
The nicest thing about all of this technology is how invisible it is to the driver. The only noticeable difference between the hybrid Tahoe and it’s gas powered cousin is that the hybrid engine shuts off at stoplights.
Despite a five mile-per-gallon difference in fuel economy, there is little cost benefit in buying the hybrid versus other Tahoe models. Base sticker price for the Tahoe hybrid is $49,590, as compared to $35,530 for the base Tahoe with the 4.8-liter V8, or $39,935 for the more powerful 5.3-liter engine.
Assuming the average driver travels 15,000 miles annually and pays four dollars per-gallon for regular unleaded gasoline, the hybrid owner will pay $2857 for a year’s worth of gas, versus $3529 to fuel the V8 models listed above. It will take almost fifteen years for the hybrid owner to make up the price difference between his car, and the Tahoe with the 5.3-liter V8.
Though buyers pay a premium for the hybrid technology, the biggest reason for the price difference is content. The Tahoe Hybrid comes with standard equipment that is optional on most other grades, including the third-row seats, navigation system, three-zone climate control, a Bose premium sound system, rear backup camera, and XM satellite radio.
It’s the same pricing strategy that Toyota and Lexus use for their hybrid sport-utility vehicles, the Lexus RX 400h and Highlander Hybrid. Simply put, the hybrids are only available as fully-loaded vehicles.
How the technology works
A digital display in the gauge cluster tells the driver which mode the gasoline engine is operating in. At start-up, the engine operates in “open loop”: it has to reach operating temperature before computer controls take over. During this period, the engine runs on eight cylinders.
The point at which computer controls take over is called “closed loop: the computer uses readings from the exhaust stream and other electronic sensors determine engine load. When power demands are low, the Tahoe runs on four cylinders. The electric motors augment the gas engine’s power, so it can stay in four-cylinder mode in some high-speed driving situations.
During hard acceleration, when towing or driving uphill, the engine runs on all eight cylinders. Electronic controls have the ability to detect minute changes in driving conditions,, to minimize the amount of time the engine runs on full power. As a result, the hybrid averages two miles-per-gallon more than gas-powered Tahoes on the highway.
The mileage difference is much greater in the city: about seven miles per gallon. The engine rarely shifts out of four-cylinder mode during low-speed driving. It shuts off at idle, and electric motors supply power for the truck’s accessories.
The Tahoe Hybrid has an electronic air conditioning compressor. It doesn’t run off the gas engine like conventional air conditioning systems, so it can keep the car cool when it’s stopped at a light.
Interior designed for active lifestyles
The Tahoe’s interior is designed for people who spend a lot of time in their cars, and carry a lot with them. Three rows of seating hold up to eight passengers. Second and third-row seats tumble forward to produce a long cargo floor. Tumbling the third-row seats forward creates enough space in back for a road bike with the front wheel removed.
Front-row passengers get two-stage heated seats with power adjustments. A three-zone climate control system has separate controls for the driver, front passenger, and second-row passengers. Three ceiling vents circulate air through the back of the car. An optional power sunroof ($995) adds more ambient light.
The Bose premium audio system includes an AM/FM radio, MP3 plug-in, CD player, and a three-month subscription to XM satellite radio. An optional rear-seat DVD system ($1295) keeps kids in the back entertained on long road trips.
There are plenty of cupholders to accommodate eight passengers: the front doors also have bottle holders molded into the map pockets. There are five, 12-volt power points: on the center stack, in the center console bin, behind the center console, and to the right of the liftgate. A 115-volt inverter on the center stack lets the front passenger plug in a computer.
A screen in the center stack displays audio settings, maps for the navigation system, and a wide-angle camera view to the rear when the car is in reverse. The rearview camera assist system makes it easy to back the Tahoe into a parking space.
The Tahoe hybrid comes standard with four-channel antilock brakes, stability and traction control, front and side curtain airbags. Standard OnStar automatically notifies police and medical personnel if the airbags deploy.
The Tahoe Hybrid is built at Chevrolet’s Arlington, Texas assembly plant.
Likes: Exceptional fuel economy for a full-sized sport-utility vehicle with no sacrifice in performance.
Dislike: The hybrid is only available as a fully loaded vehicle. It’s $49,590 MSRP puts it out of the reach of many buyers.
Model: Tahoe 2WD Hybrid
Base price: $49,590
As tested: $52,780
Horsepower: 332 Hp @ 5100 rpm
Torque: 367 lbs.-ft. @ 4100 rpm
Antilock brakes: Standard
Side curtain airbags: Standard
First aid kit: N/A
Bicycle friendly: Yes
Fuel economy: 21/22 mpg city/highway
Comments: MSRP doesn’t include a $900 delivery charge.
One response to “2008 Chevrolet Tahoe Hybrid”
Fixed gear bikes are great, but they are not for everyone.
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