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GM Offers XFE Models of Full-Size Pickups and SUVs

General Motors is introducing new XFE (Xtra Fuel Economy) versions of its 2009 Chevy Silverado, Chevy Tahoe, GMC Sierra and GMC Yukon full-size pickups and SUVs. The vehicles use a combination of mechanical, aerodynamic and mass-reducing enhancements to deliver a 5% increase in EPA-estimated highway fuel economy and more than 7% improved mileage in city driving. GM introduced an XFE version of the Chevy Cobalt compact car earlier this year. (Earlier post.)

GM’s more efficient full-size pickups and SUVs are powered by a 5.3L FlexFuel V-8 (LC9) engine that’s built with a mass-reducing aluminum cylinder block and heads. The engine is rated at 320 horsepower (238 kW) and 340 lb-ft of torque (461 Nm) in Tahoe and Yukon and 315 hp/235 kW and 338 lb-ft/458 Nm in Silverado and Sierra. The engine is backed by a Hydra-Matic 6L80 six-speed automatic transmission (with high-capacity cooling on Silverado and Sierra).

Aero enhancements make Silverado XFE and Sierra XFE models the most aerodynamic full-size pickups in the industry, with a “Best in Class” 0.412 coefficient of drag (cd). The pickups join the Tahoe Hybrid and Yukon Hybrid as the most aerodynamic full-size SUVs at 0.349 (cd).

A rear axle equipped with a fuel-saving 3.08 ratio is also standard on all XFE models. Lightweight aluminum wheels and low rolling resistance tires (with higher tire pressure) also are included on all models.

The new XFE models achieve 15 mpg US (15.7 L/100km) city and 21 mpg US (11.2 L/100km) highway mileage ratings versus comparable non-XFE models’ 14/20 ratings. Towing ratings for the Tahoe and Yukon are unchanged, while the Silverado and Sierra increase from 6,600 pounds (2,994 kg) to 7,000 pounds (3,175 kg) due to the new, six-speed transmission and high-capacity cooling package.

All models carry the XFE name badge and are offered in the LT trim for Silverado and LS and LT trims for Tahoe. Sierra XFE comes with SLE trim and Yukon XFE is offered with SLE and SLT trim. Most regular-production options for all models are available. Silverado XFE and Sierra XFE are offered in 2wd crew cab body styles only. Production begins this fall.

In addition to the XFE models, GM already offers two-mode hybrid versions of the Tahoe and Yukon that achieve up to a 50% improvement in city fuel economy and coming in the first half of 2009 are the Silverado (earlier post) and Sierra (earlier post) two-mode hybrids . The hybrid pickups offer up to 25% overall increased fuel economy and greater than 40% improved mileage in city driving.

Other unique content and features for Silverado XFE and Sierra XFE include:

  • Soft tonneau cover (improves aerodynamics)
  • Extended front lower air dam (improves aerodynamics)
  • Lowered suspension and revised chassis tuning (improve aerodynamics)
  • Aluminum lower control arms (reduce mass)
  • Aluminum spare wheel (reduces mass)
  • Seventeen-inch aluminum wheels (reduce mass)
  • Automatic locking rear differential
  • Trailering package
  • Low rolling resistance tires

Other unique content and features for Tahoe XFE and Yukon XFE include:

  • Lowered suspension and revised chassis tuning (improve aerodynamics)
  • Aluminum lower control arms (reduce mass)
  • Aluminum spare wheel (reduces mass)
  • Eighteen-inch aluminum wheels (reduce mass)
  • Automatic locking rear differential
  • Trailering package
  • Low rolling resistance tires

“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. 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.

—Gary White, GM North America vice president and vehicle line executive for full-size trucks.

GM has seen combined sales of the four brands (Tahoe, Silverado C-K, Sierra and Yukon) drop 25% to 441,946 units for the first seven months of the year compared to the same period last year. Pickup truck (Silverado and Sierra) sales represented 81% of those combined 2008 sales to date, with the Silverado alone accounting for 60% of the sales of the four (264,309 units January-July 2008). The four brands accounted for 24% of all GM vehicles sold January-July 2008, down from 26% of all vehicles sold for the same period the prior year.


Dan A

Andrey Levin:
At least for the Chevy impala, their V-6s have cylinder deactivation. It's 4 cylinders that can't do cylinder deactivation (due to vibration issues).

Brian P

I don't think the Impala V6 has cylinder de-activation (the V8 does). But, Honda uses it in selected versions of the V6 in the Pilot and Odyssey - but only in conjunction with a fancy noise-cancelling system that uses the audio system to somehow offset the vibration in the powertrain!

The 3.6 "high-feature" direct-injection V6 might - and I stress MIGHT - do better on fuel, but who's going to pay for that. Likewise with the hydraulic (or otherwise) hybrid. Lots of base model trucks are "contractor specials" for which the only sales consideration is the lowest possible price. GM's cylinder de-activation has the advantage of not costing much to produce.


Honda does have cylinder deactivation on their four cylinder hybrid Civic, and it works well ( I wonder if the inertia/power of the electric is what makes it balance so well). I doubt GM has evolved much from their 8-6-4 Cadillac fiasco in the 70's ( once bitten they rarely believe they can do it right).On demand turbochargers or superchargers can make any small engine perform at superman levels ( much like nitrous turns a smogger into a dragster).
The fact that big truck sales have gone into the dumper is a clue that not everyone wants a big engine in a truck. And there is a business case for putting small engines in big trucks so sales continue instead of closing truck building plants for 3 months whenever the unsold inventory exceeds 120 days.Even GM's bean counters should be able to figure that one out ( maybe the union could tell them 90 day vacations at 90% salary is not a good business practice, LOL, asif).

Andrey Levin


Civic hybrid deactivates all four cylinders on engine over-run, to cut on pumping losses (engine braking) while vehicle is coasting.

Any way, 5-7% fuel efficiency gain from cylinder deactivation does not worth all troubles of torsional vibration on crankshaft due to intermittent delivery of power, when only three cylinders are operational.


Hey, I'll give them some credit for the XFE program effort. Will it save a huge amount for one driver? Maybe a little. Will it save a huge amount overall for the fleet? Who knows. It depends on how many models it's fitted as standard on, and how many people buy them. Truck sales are in the toilet anyway. GM is full of good engineers, and I'm sure they know what the best solutions to raising truck mileage are, i.e. small diesels like in Europe, more 4-cyl options, etc. But their hands may be tied by the economics involved, production constraints, etc. Who knows. So they have to go with the 'less-than best' options -- which arguably should have been done a long time ago. I mean look at the moribund mild-hybrid "Greenline" programs at Saturn/Chevy. How's that whole deal goin.... It would be nice to bend the ear of a GM insider over a cup of coffee.


I have to use a truck quite a bit for work. The question I have is why don't they give us a durable, efficient mid-size pickup, like a Tacoma, Ranger or S-10? The current mid-sizers have too light of suspensions and just don't seem to hold up like their bigger siblings. A contractor-specific mid-size model would sell like mad.

Keep the big trucks big so they work for pulling 10,000 lb loads, and make a mid-size so it can do daily duty pulling 5k and hauling a load of lumber. A 150 hp turbo diesel like they have in the Sprinter would be ideal, and we could get some pretty good mileage numbers on a highly practical vehicle.

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