GMC Sierra Hybrid
Test Drive
By Noel Adams

On February 29, 2004 I attended the GM Auto Show in Motion event held at Hollywood Park in Inglewood. This event gives drivers the opportunity to test drive a variety of GM vehicles and compare them to the competition.

Towards the end of the event I wondered over to the Truck section and was surprised to see that they had a Hybrid GMC Sierra Pickup there. I was even more surprised to find out that they would let me take it for a spin.

The HEV version of the Sierra pickup is powered by a 5.3 liter Vortec V8 supplemented by a 42V Lead Acid (PbA) battery connected to a motor generator that provides auto stop and start. GM claims that this boost fuel economy from 15mpg to 17mpg for the four-wheel drive version that I test-drove. The system is a mild hybrid; the electric motor does not provide additional power for starting and acceleration, it only shuts down the motor when the truck is stationary.

The first thing I noticed about the car was that although the fit and finish seemed quite good and the inside was well appointed, the crew cab doors needed a good slam to close them properly. The front seat was roomy and the all-way adjustment on the seats made it easy to get comfortable. The rear seats weren't exactly roomy but were big enough for children or to get a crew to the work site.

Creeping forward in the line for the test track I noticed that when I trod on the brake lightly the engine kept running. Applying a little more pressure caused the engine to cut out. As I lifted my foot off the brake the engine started up again seamlessly.

Acceleration off the line was quit acceptable and handling through the curves was surprisingly precise. While slowing for curves there was no apparent drag from regen braking. The test track was too short to really push this truck so I wasn't able to see how well the brakes worked in an emergency stop but they seemed fine for general driving. The ride was rough, as you would expect from a pick-up truck.

The big selling point for this vehicle is going to be the power outlets. The 42V PbA battery is boosted up to 110V and rectified so that it will provide 20amps through 2 power outlets. This is plenty of juice to run power tool or provide power for a campsite.

The GMC sierra hybrid will find plenty of buyers who need the ability to generate their own power but whether the modest 2mpg gain will be worth the extra cost to the average truck buyer remains to be seen. According to the GM rep I talked to, expect to see the Sierra HEV in showrooms in the fall.

(Contact Noel)