DETROIT - General Motors plans to give its 2007 mid-sized pickups and the Hummer H3 SUV more powerful engines.
The current 3.5-liter, five-cylinder in-line engine in the 4,700-pound H3 is rated at 220 hp. GM says the 2007 H3 coming in the fall will get a 3.7-liter version of the in-line five-cylinder engine. Horsepower will jump to 242.
The GMC Canyon and Chevrolet Colorado pickups also will be available with the 3.7-liter engine as an option. And the base models of the mid-sized trucks will get a bump in power from a slightly bigger engine. The 175-hp 2.8-liter four-cylinder is being replaced by a 185-hp 2.9-liter version of the four-cylinder engine.
Sales of the two trucks have plummeted. The Canyon's sales of 8,625 units through May are off 41.8 percent; the Colorado's sales of 36,208 through May are down 35.5 percent.
Both new versions of the four- and five-cylinder engines have bigger pistons, redesigned cylinder heads, larger valves, a redesigned oiling system and other improvements.
The increase in displacement and engine size won't hurt fuel economy, says Tom Sutter, chief engineer of GM's in-line four-, five- and six-cylinder engines.
"Our goal here has been to increase performance without compromising fuel economy. We've been able to do that with some of the technology we have in the engine," Sutter said.
For example, the bigger valves help the engine breathe better, which means it runs more efficiently. As a result, the 2007 EPA fuel-economy ratings of the H3, Canyon and Colorado will stay the same.
The H3 is rated at 16 mpg city and 20 mpg highway with a manual transmission.
Reviewers have criticized the H3 in its first year on the market for its lackluster acceleration. But sales have been strong, with about 23,000 units sold through June.
Sutter said the engine upgrades didn't come about because of consumer complaints but were part of GM's plan to continually upgrade products.
You may e-mail Richard Truett at [email protected]