Despite initially launching in just the Crew Cab configuration, the lineup of 2014 GMC Sierra and 2014 Chevrolet Silverado trucks will eventually grow to include three cab sizes and three bed lengths. Oddly enough, our first look at the Regular Cab bodystyle has arrived in a General Motors press release discussing the aerodynamics of the new truck, with an image showing a Sierra Regular Cab testing in the wind tunnel. GMC's website says that Regular Cab and Double Cab models will be available by summer.

While it really didn't take too much imagination to figure out what the two-door version would look like, this Regular Cab Z71 looks pretty sharp with its standard-length (6.5-feet) bed – a longer bed will also be offered. In regards to the aero tuning of the 2014 Sierra, these images show just how far GM has gone in maximizing the truck's fuel efficiency and reducing its noise, vibration and harshness (NVH) levels. Interestingly, the press release shows visual evidence that keeping the tailgate up is best for aero – there's always been some Mythbusters-level contention about such things –but GM also says that adding tonneau covers (preferably soft) and running boards can also help improve the overall aerodynamics. Scroll down for all of this aero info in the official press release.
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GMC Pickups 101: Busting Myths of Truck Aerodynamics

2014 Sierra gains fuel economy, quietness from time in wind tunnel


DETROIT – The all-new 2014 Sierra full-size pickup truck spent more development time in a wind tunnel than any GMC pickup before it, resulting in design changes that benefit both fuel efficiency and interior quietness.

To achieve improved airflow, aerodynamic engineers like Diane Bloch examined every millimeter of the truck to find areas of improvement, debunking some popular myths along the way.

To study the way air passes over, under and around the Sierra, engineers used General Motors' state-of-the-art Aerodynamics Lab, a 750-foot-long tunnel through which a 43-foot-diameter fan powered by a DC electric motor with the equivalent of 4,500 horsepower can generate winds of up to 138 mph. Aerodynamic advancement is one reason why the 2014 Sierra will be the most fuel-efficient V-8 pickup on the market.

"We can't stop air; we can only guide it through the path of least resistance. It's like electricity, without the shock," said Bloch, GM aerodynamic performance engineer. "The biggest misconception is that it's all about single components. But a certain side mirror design doesn't create a certain amount of drag, its interaction with the rest of the vehicle does."

For example, a new air dam below the 2014 Sierra's front bumper successfully reduces drag because it directs air toward the ground and away from the truck's rough underbody. And Sierra's ducted flow path between the grille and radiator prevents air from swirling inside the truck's front cavities.

Even the top of the Sierra's tailgate and the center high-mounted stop light are optimized to guide air cleanly around the truck. And because Bloch's team detected unwanted airflow between the cab and bed, new sealing has been added.

"We discovered that in the computational analysis we perform," said Bloch. "The most harmful air between the cab and bed was coming over the cab and down through the gap, so we paid the most attention to that specific area."

The pickup market has a great number of available aftermarket accessories, and Bloch says those have varying impact on aerodynamics. Add-ons like bug deflectors on the hood, wider tires or aftermarket bumpers can raise the drag coefficient, which is the measure of how air pushes on a vehicle as it moves down the road. The result: added noise and increased fuel consumption.

A long-disputed topic among truck owners is whether a tailgate raised or lowered is better for aerodynamics, but Bloch says a tailgate in the up position is more aerodynamically efficient. As air flows over the truck, it falls over the cab and pushes forward on the rear of the truck. With the tailgate down, the benefits of that airflow are diminished.

"Replacing the tailgate with an aftermarket net is worse than having no tailgate at all," Bloch said. "Imagine dragging a solid object and a fishing net through water. The net is going to require more muscle."

So what accessories can truck owners add to help aerodynamics? Tonneau covers for the bed help smooth airflow over the truck, and Bloch says soft covers are more beneficial than hard covers because they form to how the air wants to flow. Running boards can also help air flow smoothly down the truck's sides.

"Round, tube-style running boards can provide a minor improvement to the truck's drag coefficient," said Bloch, "Fully integrated, flush-mount running boards are even better."

GMC has manufactured trucks since 1902, and is one of the industry's healthiest brands. Innovation and engineering excellence is built into all GMC vehicles and the brand is evolving to offer more fuel-efficient trucks and crossovers, including the Terrain small SUV and Acadia crossover. The 2014 Sierra half-ton pickup boasts all-new powertrains and design, and the Sierra Heavy Duty pickups are the most capable and powerful trucks ever built by GMC. Every retail GMC model, including Yukon and Yukon XL full-size SUVs, is now available in Denali luxury trim. Details on all GMC models are available at http://www.gmc.com/, on Twitter at @thisisgmc or at http://www.facebook.com/gmc.


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    • 1 Second Ago
  • 75 Comments
      domingorobusto
      • 1 Year Ago
      It's very surprising to me how much more I like this than the Silverado. The Silverado is a borderline ugly truck IMO, whereas this is actually very attractive. I still find the proportions very cartoonish, but this is worlds better than it's Chevy brethren. This is why I'm glad GMC is still around.
      paqza
      • 1 Year Ago
      So can I get it with a 3.0 L diesel?
      Luke
      • 1 Year Ago
      Man that thing is BLOCKY. Still looks better than the Silverado.
      zoom_zoom_zoom
      • 1 Year Ago
      LOL, they put the smoke almost at the top of the hood. Imagine how turbulent the air flow would be if the smoke was hitting that front bumper. BTW, do SEMI trucks even have grills and bumpers that large. Compensating much?
      Carbon Fibre
      • 1 Year Ago
      Using aero vapor on a truck not intended for racing seems a bit of a joke, really.
      • 1 Year Ago
      [blocked]
        CBJMNWLD
        • 1 Year Ago
        DERP I\'m Laser (or lazy). We know you have a keyboard. You\'ve also proven there is no brain typing on it.
        gazingwa
        • 1 Year Ago
        Drink the Kool-Aid much? The Silverado/Sierra twins have beat F series quite a few times. They just report their sales separate giving Ford the ability to claim best selling for so many decades. The simple to work on pushrod Chevy V8 is a great engine and proves OHC isn't really needed in this application, pushrods work great if you design them right. Don't get me wrong, I like Ford, I have an F150 and a Fusion in my driveway but seriously, get a clue.
          vizcarmb
          • 1 Year Ago
          @gazingwa
          You need to stop drinking the kool aid yourself
      zoom_zoom_zoom
      • 1 Year Ago
      LOL, aerodynamics. If GM was worried about the cd on this, they would lower the hood about a foot and reduce the size of that grill. It doesn't need to be anywhere near that large. Same basic engine under the hood of the Corvette for example.
        gazingwa
        • 1 Year Ago
        @zoom_zoom_zoom
        Please let tell me more about your engineering degree and understanding of pedestrian impact requirements and the amount of cooling required to pull 10,000lbs.
          vizcarmb
          • 1 Year Ago
          @gazingwa
          your funny... you think you're smart. did you forget that this is the internet and no one gives a ##!@
          A_Guy
          • 1 Year Ago
          @gazingwa
          @viszcarmb: Apparently the 3 people that downvoted you gave a ##!@.
      Soccer Mom
      • 1 Year Ago
      Given its shape, I expect the air simply bounce back, as if it hit a vertical wall. Why do they even bother with the wind tunnel?
        icon149
        • 1 Year Ago
        @Soccer Mom
        And that is why you don't design cars.
        paqza
        • 1 Year Ago
        @Soccer Mom
        I guess you missed the main photo from this post, as it's very clearly having its aerodynamics tested.
          paqza
          • 1 Year Ago
          @paqza
          Hmm...cut off the second part. "And it does well."
      muspod
      • 1 Year Ago
      oh yeah...thats aerodynamic... and pep boys headlights.. great job govt mtrs..
      X8664
      • 1 Year Ago
      Typical American garbage. No one outside the states will buy this crap.
        kritzah
        • 1 Year Ago
        @X8664
        Thanks for the thought. Hope posting your anti-american feelings on an american blog helps satisfy your egocentric elitism. But next time, just grab a beer? -- it works better.
      mylexicon
      • 1 Year Ago
      Grill too small. Nose too low. Windshield too swept. Fuel economy too high. Looks like it was made for Barbie. 1/10 Would not buy.
        dovegraybird
        • 1 Year Ago
        @mylexicon
        Even if your comment had merit, that means then that 9 in 10 would buy. I think those numbers are good enough for GM
        RJ
        • 1 Year Ago
        @mylexicon
        Comment too clueless.
      Davidsky
      • 1 Year Ago
      Trucks look hottest in short bed regular cab versions. This one looks fantastic!
        Rover
        • 1 Year Ago
        @Davidsky
        This truck looks sick, can't wait to see the Chevy version!
        paqza
        • 1 Year Ago
        @Davidsky
        That's also one of the least versatile arrangements...
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