GM putting XFE and hybrid models on fast track

General Motors is serious about keeping its profitable full-size pickup and SUV business going even as gasoline prices remain at historic highs, and one way to do that, the automaker believes, is to improve these vehicles’ fuel economy.

For 2009, that means introducing new gasoline-electric hybrid versions of the Chevrolet Silverado and GMC Sierra pickups, as well as offering new XFE ("Xtra Fuel Economy") gasoline-only models of the Silverado and Sierra, as well as the Arlington-built Chevrolet Tahoe and GMC Yukon full-size sport utilities.

The XFE models arrive first, this fall, followed by the new hybrid pickups, which GM says will go on sale "during the first half of 2009," although no exact on-sale date has been announced.

GM introduced the XFE concept on special models of the 2008 Chevrolet Cobalt sedan and coupe, as well as the ’08 Pontiac G5 coupe, giving both of those vehicles higher fuel economy than their non-XFE counterparts.

For example, the Cobalt XFE equipped with a 2.2-liter four-cylinder engine and five-speed manual transmission is EPA rated at 25 miles per gallon city/36 highway, compared with 22/31 for the Cobalt with a four-speed automatic and the 2.2-liter engine.

The improvement in fuel economy for the big pickups and SUVs won’t be quite as dramatic, but will be significant nonetheless.

"The vehicles use a combination of mechanical, aerodynamic and mass-reducing enhancements to deliver a 5 percent increase in EPA-estimated highway fuel economy and more than 7 percent improved mileage in city driving," GM said in announcing the new models.

For the Silverado and Sierra, as well as the Tahoe and Yukon, the EPA ratings for the XFE models will be 15 mpg city/21 highway versus 14/20 for the regular models, using a 5.3-liter V-8 engine and six-speed automatic transmission.

"We are pulling out all the stops to deliver a more-efficient package for customers who need the capability of full-size pickups and SUVs and want the very best fuel economy," said Gary White, GM’s North America vice president and vehicle line executive for full-size trucks.

"Our pickups and SUVs are already the fuel economy leaders of their respective segments, but our engineers knew greater efficiency was achievable. We fast-tracked the XFE models to get them into dealer showrooms as quickly as possible."

The XFE pickups will be available only with two-wheel drive and in the crew-cab body style, GM said. The Silverado XFE will be offered in the LT trim level, while the Sierra XFE will be sold in the comparable SLE trim level. Most of the options available on regular Silverado and Sierra models will be offered on the XFE versions, as well.

With the SUVs, the Tahoe XFE will be offered in LS and LT trim levels, and the Yukon in the similar SLE and SLT trims. Both will be available in two-wheel drive only. Four-wheel drive almost always uses more fuel.

The increased fuel efficiency does not affect the performance or capability of the vehicles, GM said. Tow ratings for the Tahoe and Yukon remain the same in the XFE versions, but the Silverado and Sierra models actually have higher tow ratings – 7,000 pounds. The rating for the regular models is 6,600 pounds.

GM attributed the increase towing capacity to the new six-speed transmission and a high-capacity engine-cooling package.

The 5.3-liter engine has a lighter aluminum cylinder block and heads, and is rated at 320 horsepower and 340 foot-pounds of torque in all four of these vehicles.

Also helping is a fuel-saving 3.08 ratio rear axle, exclusive to the XFE models. Other enhancements for fuel efficiency include lightweight aluminum wheels and low-rolling-resistance tires operating at higher pressure.

The pickup XFE models also will have a soft bed cover, front lower air dam, lowered suspension and revised chassis tuning to improve aerodynamics. To decrease weight, the trucks will have aluminum lower control arms and wheels, including the spare. An automatic locking rear differential is included as well.

Tahoe and Yukon models will have most of these same aerodynamic and weight-reduction features.

The enhancements are designed to make the Silverado and Sierra XFE models "the most aerodynamic full-size pickups in the industry," GM said. Their coefficient of drag, the measurement of how easily the vehicle moves through the air, will be 0.412.

The Tahoe and Yukon hybrid have the same enhancements, and are the most aerodynamic full-size SUVs on the market, GM said. They have a 0.349 coefficient of drag.

All of the XFE vehicles will carry special badges.

They will go into production in early fall, GM said, then will begin arriving at dealerships shortly thereafter.

Already, GM has hybrid versions of the Tahoe and Yukon on the market. Those offer a 50 percent improvement in city fuel economy over the basic gasoline models. The Tahoe and Yukon hybrids are EPA rated at 20 mpg city/21 highway (two-wheel drive).

The hybrid pickups will use the same technology and drivetrains as the SUVs, and will offer up to 25 percent overall increased fuel economy and a more than 40 percent increase in city mileage, GM said.

The automotive columns of G. Chambers Williams III have appeared regularly in the Star-Telegram since 1995. Contact him at 210-250-3236; chambers@ star-telegram.com.