What is It?
GM 4.2-liter Vortec inline-six 275 horsepower/275 pound-feet 4L60-E four-speed automatic
What We Like
The General's spunky I-6 has a near-linear torque curve, once the rev counter crests 3000 rpm. From a standing start, initial acceleration's a bit soft, a direct opposite from the hammer blow delivered by the Jeep's Hemi V-8. Inline-sixes are generally smooth runners, and this power head is well balanced from idle throughout the powerband. The transmission has smooth, yet positive shifting, and gear-holding on grades was near perfect.
What We Don't Like
With its competition running an additional two cylinders, the editors expected a larger spread in EPA numbers, but the Envoy bettered the competition by only a couple mpg. Maximizing pulling torque requires high revs, and the 4200 Vortec gets buzzy at the upper end of the tach. Manually downshifting the tranny on downhill grades, the 4L60-E is a bit slower to engage than we prefer, and GM could step up to the plate with an extra cog for better flat-freeway fuel economy.
How It Works
Introduced on the Chevrolet TrailBlazer and GMC Envoy in 2002, this powertrain was a departure from the then-standard V-6 fare. Inline-six engines have been around for decades, and, for the most part, are powerhouses for their displacement. The 2400 Vortec is no exception, providing velvet smoothness with refined power and offering better fuel economy over V-8s. GMC offers a 5.3-liter V-8 option on the XL edition of the Envoy, one we'd vote to have available on the standard model. As the saying goes, there's no substitute for cubic inches, and when towing or carrying a heavy load, the Envoy would benefit from two additional cylinders.