Tahoe Hybrid Provides Silent Operation

Light & Medium Truck, Apr 2008 by Galligan, Jim

A week of driving a 2008 Chevrolet Tahoe Hybrid in Northern Virginia turned up few noticeable differences from that of a standard Tahoe, something General Motors probably likes to hear.

The 2008 HybridTahoe features GM's dual-mode powertrain system - a 6.0-liter V-8 gasoline engine in tandem with a battery pack and two electric motors in the transmission.

The first mode is a typical hybrid system, in which the electric motor and engine work together or independently. In the second mode, motor and engine work together to produce higher speeds and handle heavier loads.The electric motor runs almost constantly, allowing the 8-cylinder gasoline engine to run on just 4 cylinders with electric assist.

The powertrain operated smoothly and quickly, moving seamlessly and, in most circumstances, unnoticeably back and forth among engine, hybrid and battery power. Most of the time, the only way the driver notices changes is glancing at the dashboard display to see which mode is active.

The Tahoe XLT model is quiet anyway, and the hybrid test model seemed even quieter.The most noticeable difference between it and one with engine-only power is the silence when running under battery power or when stopped, such as at stop lights, when the auto mode kicks in. It is easy to get used to the quiet.

There was no hesitation when accelerating from a stop, and the battery powers the motor in soft startups up to about 10 miles per hour when the engine or hybrid system takes over.

The truck has plenty of pickup and power, something that is needed for a 7,100-pound truck with a towing capability up to 6,200 pounds. But that power will cost you plenty of fuel if you don't have the patience to accelerate gradually. Fuel performance plummeted to anywhere between 3 miles per gallon to 7 mpg on fast startups, according to the instant fuel economy readout. However, it also rose to the 20s - and higher, depending on different factors - when cruising in V-4 mode. GM rates the 2008 Tahoe Hybrid at up to 21 mpg city and 22 mpg highway.Ten days with one model may be too short a time to attest to that, but after more than 330 miles, with about 200 on country routes, the average fuel economy was 19.4 mpg, again, according to the fuel economy readout.

The hybrid offers most of the same features as the XLT model but with the larger, 6.0-liter V-8 engine. Some of those features include active fuel management, which cuts out four of the eight cylinders when cruising, Stabilitrak electronic stability control and Ultrasonic rear parking assist. This feature includes a rear camera that comes on when the truck is put in reverse and provides a dashboard display and an audio signal that beeps when the bumper is about one foot from an obstruction.

The manufacturer's suggested retail price for the 2x4 2008Tahoe Hybrid starts at $50,490, a 46% premium over the MSRP of the standard 2008Tahoe.