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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.



It looks like they are learning nothing. 320 HP? Maybe for the guy with Nascar fantacies, but there is no need for that much power. A 1977 Corvette had 170 HP.

Lou Grinzo

A certain metaphor about deck chairs and a famous sinking ship simply leaps to mind when reading this article.


In a world of squeezing fuel economy, we should improve our units a little. This article claims that the fuel economy was improved 7% HWY from 20 MPG to 21 MPG. In my math, 20 to 21 is 5% improvement. However, it could be that it improved 20.0 to 21.4 which would, in fact, be 7% improvement.

IMO, the EPA needs to start listing fuel economy with at least three significant figures.

Also, GM should have done these things a long time ago...


Small steps are better than none.
Less horsepower would be pointless.
A smaller engine might get another 1 or 2 % and make the non-buyers happy but would not sell.
Less is more; but only when it's the other guys truck.
I assume these engines do not (yet) have Active Fuel Management or variable valve timing?
Again, a 6% reduction in a large fuel bill is good.


Hi ToppaTom, It's good to increase economy, but GM could have done much better. There is no need for 320 HP. The huge garbage truck that wakes me up in the morning only has 270 HP. If GM would use a smaller engine the internal friction losses would be less. A 4.3 liter 6 cylinder has less ring friction than a 5.3 liter V8. I have owned 3 trucks in the past, and none of them have had more than 185 HP. I never had the need for more power when towing, though bigger brakes would have been nice.


In theory yes. But the 4.3 has seen limited development in recent years and the engine family that includes the 5.3 has better brake specific fuel consumption. I think the 4.3 still has cast iron heads. She's an oldie.

For GM trucks, the 4.3 is currently a cost reduction option, not an efficiency option.

What's frustrating is that you always hear, "Auto companies spent x amount of millions to make sure that cars get the best fuel consumption within the current limits of technology."

Well... Looks like at least 5-10% is still ripe for the taking. I think all cars should have the XFE treatment. But I suspect that marketing and competition trump the need for those extra gains. A "deep chin spoiler" probably ads a couple bucks to the cost of a car or truck for a 1-2% highway mileage advantage. In the pre $4dollar/ gallon environment, most companies would take the per vehicle cost reduction instead of the efficiency gains, slap themselves on the back and move on.

Hopefully the new efficiency minded market mentality will stick, and the competition will sway to ad those things back.


If we look over at Europe, we'll see that most large trucks there don't even come with eight cylinder engines. A 2.5-3.0 liter turbodiesel engine is considered adequate for large vans such as the VW Transporter (once the Eurovan over here), the Sprinter, which we now are lucky enough to have over here, and several other large vans from the Italian and French manufacturers. All of these full size vans get better fuel economy than GM's XFE trucks.

A note on Darren's comment: I agree we need to be more precise on the fuel economy ratings. Other people have mentioned, and I would agree with them, that we should switch to gallons per 100 miles, like Europe has liters per 100 kilometers. With a few decimal points, this would not only allow us to have a more accurate picture of every car's fuel economy, but it would make the savings of fuel consumed (or lack of savings) more transparent.

stas peterson

When will you guys learn that the EPA does not have, nor does it set, mileage standards. The Window sticker is nothing more than an arbitrary "estimate" of the mileage that a vehicle can obtain. It is no more valid then your eyeball estimate.

The NHTSA tracks the CAFE standard, measures every vehicle for mileage using a standard method that has been unchanged, since the Original CAFE back in the 1970s.

These vehicles are all 15-20% better than the very best mileage vehicle of the 1970s era.

We have actually come that far.

The very best vehicle measured with the same measuring stick back in the 1979s got 16 mpg combined. These all rate by NHTSA measurements, better than 22.7 mpg and have to, by law. Some such vehicles as these, may be as high as the mid 20s by the constant, unchanged, and legal, CAFE measuring method.

Progress happens incrementally, until a wholly new technology is implemented.


It is interesting to know that now, the average fuel economy of vehicles in the UK is almost 70% higher than that of the USA:
UK: 38 miles/US gallon
USA: 22.4 miles/US gallon

kum dollison

Pathetic - Where's the new Ecotec engine with vvt, di, and variable turbo?


Is this another GM joke?

Brian P

Few things here from someone who actually deals with the automotive business.

As far as I know, cylinder de-activation is now standard on the 5.3 V8. I could be wrong, but it would not make sense to make the "economy" version not have this feature.

Keep in mind that very tall axle ratios that bring engine RPM down, may reduce the amount that the cylinder de-activation can be utilized. What's better, 1600 rpm on 8 cylinders, or 1800 rpm on 4 cylinders. (Answer is "it depends".)

The 4.3 V6, as someone else mentioned, is a very old engine design. The 5.3 V8 uses less fuel in this application.

Regarding the power rating, the full size truck still has to do the things that a truck is expected to do. Modern engine and transmission designs can achieve high power ratings (at high engine revs) while still maintaining decent efficiency (at low engine revs). A high-winding 4-cylinder that has to work hard to make the truck move, isn't necessarily going to be any more efficient.

I don't dispute that engines and vehicles are smaller in Europe, that's obvious. North American buyers have the choice, for example, of buying a 4-cylinder Chevrolet Colorado, if that suits their needs.

GM has to make vehicles that will actually sell. Truck buyers (at least until now) have been reluctant to accept small, high-revving engines.

I have been in a truck with the 5.3 V8 with a trailer in tow through the mountains. The endless gear-shifting caused by the transmission wanting to go into economy mode while the cruise control demands more power to get up the hill was NOT very pleasant. And, if you tow a trailer like this with (for example) a Honda Ridgeline, it will not even get into top gear except when coasting. And some of you want GM to put an Ecotec 4-banger into a full size truck?

What this truck really needs is the "baby Duramax". They have it coming soon ... not soon enough, but such is how it goes with introducing new powerplants.


Well stated Brian.

Unfortunately - it doesn't do much good to engineer a hyper-efficient vehicle if few people buy it. Small improvements on high volume vehicles does more good than extreme efficiency on niche vehicles.

I may want all consumers to buy only the very best technology - but the reality is that each consumer will balance needs, wants and costs.

Why can't GM be praised for moving in the right direction? - Getting incremental (low cost) changes into service quickly and at high volumes.



I guess we'll see - between the high-cost two-mode hybrid option (large improvement, large cost increase) and this option (small improvement, small incremental cost)

The buying public will vote with their dollars on which is better.


Some people DO indeed need the horsepower (read towing capability) these trucks provide. Just because you don't, doesn't mean nobody does.

If you don't need one... don't buy one.

Bob Bastard

My question is, what ever happened to the OPTION of a 6-cyl or even, gasp, a 4-cyl engine? Remember the old Iron Duke 4-cyl engine Chevy used to offer in their trucks? I have an old 1-ton Chevy truck with a mildly modded 5.7 liter V8 with a Muncy 4-spd tranny, and I doubt it puts out any more than 200 hp. I am constantly using it to tow and haul extremely heavy (legality in doubt) loads, and I can tell you that that engine accelerates the truck, its load, and anything it is towing to a speed that exceeds a safety level that common sense would dictate. I guarantee the new Ecotec 4-cyl puts out better peak HP and torque than the old normally aspirated 350 in my truck. Just for reference, 270HP is a normal figure for heavy duty tow trucks. The horsepower numbers in new trucks, SUVs, and luxury sedans is nothing more than specsmanship. With modern technology, there is really no longer any real need for V8 engines in LDVs.


I think that OLD V8 5.7 liter GM engines were rated at
170 HP, at about 4000 or 3800 RPM, I don't know the torque, but probably more than 280 lb-ft.

Bob Bastard

Jorge, they made a ton of those engines and put them in many different apps, and the performance varied widely. I just looked up the numbers and for my year (82), it was 160 HP and 260 ft-lbs. I rebuilt my engine a few years ago, and while I was at it made some performance mods on things that needed to be replaced anyway. Although I've never had it dynoed, I'm sure it now puts out substantially more power than stock, although I doubt it puts out more than 200 HP, and my mods probably didn't do all that much for the torque. I've seen specs of 260 HP/ 260 lb-ft for the 2.0 liter turbocharged Ecotec.

Brian P

The high torque rating of the older V8 engine is why it did okay with a trailer, even in the old days of 3 speed transmissions. Torque comes from displacement (or forced induction!) Still, the new trucks with more power WILL beat it up a hill ...

And I REALIZE a turbo Ecotec 4-cyl will make enough power and torque for what most people actually do with these trucks ... but how many people would actually buy one (particularly if you go back a couple of years to the development period of the GMT900 platform - it might be different now, but due to the time and cost of powertrain certification, you just can't turn around and start building something like that tomorrow).

Question that I don't know the answer to: Is the BSFC of a turbo Ecotec really any better than that of a non-turbo 5.3. Our family's experience with turbo 4-bangers (aside from diesels) has been that they are no more efficient than a non-turbo engine that's just bigger. YES, I know you can design turbo applications for efficiency rather than power, but the marketing department (in the time period that currently-available products were in design) wanted big horsepower numbers!

As for the old "iron duke" 2.5 pushrod engine, that was never available in the full size trucks. That engine's close cousin, the 2.2 pushrod 4-banger, had trouble getting a Cavalier out of its own way.

Trucks. Need. Diesels. Period.

Bob Bastard

I would have no problems pulling a nice big boat to the lake with a full sized Chevy truck with a 2.0 liter Ecotec and a nice manual transmission. In fact my friend and I pulled his 19' Bayliner to the river with his V6 equipped Trailblazer (not even a full-size) which I'm sure does not reach the performance specs of the Ecotec.


Sorry, but I cant get excited over a 1 mpg improvement on a dinosaur. Admittedly I am basing this on the 50% discounts off MSRP that the dealers in LA are doing to move these relics. Buying at half price will pay for alot of gas. Much like their mild-hybrids, its a little too late to say they are serious. All they did was some cheap bolt ons and adjustments, I am surprised they didnt take credit for a new paint polishing compound for aerodynamic improvement!
If they want to move these hippos, they need to put their sham hybrid tranny on it and buy Honda's cylinder eliminating technology. that should be good for 5 mpg in the city ( which is where these trucks typicaly spend 95% of their time). Follow that up later by dumping the iron boat anchor and replacing it with a turbocharged engine half the size, the torque will be as good with the boost and the mileage without the boost will make people ask why they didnt do it sooner.
Diesel would be better but GM would have to buy one from Europe to get something decent.


Brian P: Who said anything about putting a high revving four cylinder in a big truck? A nice low-revving, high torque six cylinder Diesel would do the trick very nicely. Well, maybe others did, but a six cylinder Diesel would like be more fuel efficient as well as a better puller.

As for towing a trailer through the mountains, why on earth would you ever engage the cruise control to do this? And if you don't like the way the automatic transmission shifts, there is a very simple solution; buy a stick.

When will Americans learn, as Europeans already have, that there is no such thing as a 6000 pound, 500 horsepower, 9 seater SUV with all wheel drive and an 8 speed automatic transmission that gets 50mpg? (and that nobody really needs one anyway). If you need a huge truck to tow your huge boat, buy a smaller boat and then buy a smaller truck too.

Brian P

I think we have been seeing that market shift. My argument is that a truck has to be able to do the things that a truck is supposed to do ... and I fully recognize that a lot of people who have been buying these things, don't need them nor even a fraction of their capabilities.

Who's been asking about 4-bangers in a full-size truck -> Not me, but see the 10th post (kum dollison) and 16th post (Bob Bastard).

I don't question that a turbo Ecotec would be capable of making the truck move. I do question whether enough people would buy it to make it worthwhile for GM to produce such a thing - even at today's fuel prices.

Andrey Levin

V6 gasoline engine on full-size pick-up is a goner. Cylinder deactivation (of one bank of cylinders) does not work well on anything less than 8 cylinders: torsional vibration and such. And V8 with cylinder de-activation is overall more fuel efficient than V6 without.

So, it is gasoline V8 with de-activation or 6-8 cylinder turbodiesel.


a hydraulic hybrid and a small aluminum v8 with cylinder deactivation is what they need.. the infinitely variable transmission will provide the needed torque to tow a big boat. Perhaps around 3liter displacement, perhaps turbocharged.. and definitely large hydraulic accumulators.

These trucks must be able to tow, otherwise they are useless.

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