2014 Chevrolet Silverado, GMC Sierra: Better Gas Mileage From More Efficient Engines

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Even big pickup trucks will get significantly higher gas mileage in years to come, and the new 2014 Chevrolet Silverado and 2014 GMC Sierra will be no exception.

This morning, General Motors [NYSE:GM] unveiled major revisions to its pair of full-size pickups.

The many updates and improvements include all-new interiors, better connectivity for digital devices, and safety upgrades.

But giving the new trucks better fuel economy was one of the most important tasks for the design team.

The company has not yet released power, torque, or gas-mileage ratings for any of its new trucks, which will go on sale next year.

The gas-mileage champ among its current pickups is the 2012 Silverado 1500 rear-wheel drive model, which is rated at 17 mpg combined.

The new models will clearly improve on that number, although many modern pickup trucks exceed the maximum vehicle weight for which fuel-efficiency ratings are issued..

GM said its new trucks will offer three different engines, two V-8s and a new V-6. All retain the classic pushrod valvetrain that the company says make them smaller and more compact than overhead-cam engines.

But the blocks and heads of the three new engines are cast in aluminum, to cut weight substantially over the traditional cast iron. The engines also feature gasoline direct injection, variable valve timing, and cylinder deactivation under light loads.

All those technologies are aimed at squeezing the very last miles out of every gallon of gasoline in vehicles that, by their nature, are large, heavy, powerful, and far from aerodynamic.

The company has not, however, followed archrival Ford in offering a downsized, turbocharged V-6 with the power of a larger V-8. Instead, it has forgone the expense and compexity of turbocharging and optimized all three engines.

2014 Chevrolet Silverado 1500

2014 Chevrolet Silverado 1500

Enlarge Photo

GM calls its all-new engines the "EcoTec3" family, and says they're "the most technologically advanced engines ever offered in light-duty pickups."

The smallest of the three is a new 4.3-liter V-6 that can be viewed as three-quarters of the larger V-8s and is produced on the same engine line in Tonawanda, New York.

While its 90-degree block angle isn't ideal (V-6es are naturally smoothest with a 60-degree block angle), GM says it will have sufficient torque to power even the larger Crew Cab pickup truck models in heavy-duty towing and hauling uses.

There are also 5.3-liter and 6.2-liter V-8 engines, which will provide the usual high towing capacities in the most powerful models that are a boasting point for all pickup makers.

The heads of the new engines have been significantly redesigned around the direct injection, with valves and manifolds repositioned to take advantage of the more precise fuel delivery.

The projector-beam headlamps of the 2014 Chevrolet Silverado 1500

The projector-beam headlamps of the 2014 Chevrolet Silverado 1500

Enlarge Photo

The cylinder deactivation--termed Active Fuel Management--is expected to provide significant increases in efficiency under light loads, for instance when the truck is cruising at a steady speed on a flat road.

Under full-power conditions, the engines run as V-8s or a V-6. As load decreases, the system shuts off fuel and deactivates the valve lifters to a pair of the V-6 cylinders and to four of the eight in the V-8.

The switch happens in less than 20 milliseconds, and effectively converts all three engines into V-4s.

All three new engines have a higher compression ratio of 11.0 to 1, but are designed to run on regular fuel.

Other improvements include greater oil capacity, revisions to the cooling system, individual ignition coils, and plastic rocker covers with integrated positive crankcase ventilation.

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Comments (11)
  1. The fact that GM's PR machine is already cranking out statements about its custoemrs wanting performance and power over mileage tells you what you really need to know about where they'll come in on mileage. No turbocharging, grill shutters not expected (unlike the new Ram), only a 6-speed A/T, etc... GM's official response is that if consumers don't need the higher power, unlike Ford and Chrysler, GM offers midsize pickups, but given tepic sales in the past, I think this is a mistake, especially after such a long delay.

    Incremental improvement, yes, meaning I'd be shicked if they even match the current Ram or F-150.

  2. Although I agree that GM could have done more. But I am NOT necessarily agree that GM needs to follow Ford's approach with its Ecoboost line. So far, the Ecoboost line has some questionable recalls and Ford's own turbo lines aren't exactly known to be reliable. GM's tweak on "tried and true" Pushrod engines might NOT be a bad idea in this case.

    Teh grill shutters only help at high speed highway cruising. From what I see, most full size pickup drivers don't drive that fast, especially when they are towing. And under loading, those extra cooling are more important than 1 to 2 MPG...

  3. @Robok2: If you know the pickup market, buyers DO value power and towing performance first, though obviously fuel efficiency has come to the fore as well over the last few years.

    I'll be interested to watch the results of the two different strategies used by GM (which will have two if not three pickup sizes, see below) and Ford, which will sell you a very, very cheap full-size F-150 if you say you want something smaller. I think some people would buy a smaller pickup who won't buy a huge, hulking F-150, but Ford says its customer data says differently. Which is why it'll be fun to watch.


  4. John, the sales figures for the last few months don't bode well for GM in any sense at all. And the Ford pickups aren't really small in the sense that they can pull almostt as much. Just a baffling decision by GM given the length of time they had for this launch and they are being attacked 80/20 in the main automotive publications. Just check out comments at Automotive News or any other one you choose.

    Truck buyers are used to big V-8s, yes. But towing as much with better mileage is a no-brainer and the market is showing that and will continue to show it. People who need heavy duty trucks will simply continue to buy the various HD versions, as they always have.

    Being worst in class is never good. Savings of $600-$800/year adds up.

  5. @Robok2: Well, GM has said for 9 months now it would build up pickup inventory before the lengthy plant shutdowns for retooling. (Not sure why body-on-frame vehicles seem to take so long.) They miscalibrated. Now, more $$$ on hoods.

    Agree these trucks seem somewhat underwhelming. I have a suspicion there's more coming on the powertrain front. GM's small diesel V-8 still sits on the shelf, for instance: development finished, then mothballed in 2008 or so. There may also be a beefier version of eAssist for truck engines. And so on.

    Agree the market will decide. I'm glad GM is just waiting for EPA ratings to come out, at least, rather than Ford's gradual + selective striptease....

  6. I was hoping GM would offer some kind of "plugin hybrid" Full Size Pickup trucks. Especially with its Voltec powertrain configuration and the potential efficient generator, it would be a nice feature to have onboard the truck so many people in construction wouldn't have to carry an additional noisy generator...
    I would pay extra couple thousands for that feature.

  7. @Xiaolong: I'm sure GM doesn't (yet) have a plug-in hybrid pickup ready yet. Remember their first volume plug-in, the Volt, is only in its third year.

    However, remember also that Via Motors has a GM connection in the form of Bob Lutz. You never know.

  8. I know. It is all about "bragging power". MPG is rarely the top 5 reason for buying a truck (except for the case of diesel for heavy towing. But truck buyers pay a very expensive upfront fee for those diesel options). Power, towing, acceleration, payload are usually the top features that buyers look for.

    I would think the Voltec would offer something unique in terms of onboard generator (beside the hybrid). It would be very useful for people who do construction work on remote site or during emergency situation.

    There is nothing like bragging to your work buddy that you got a 100KW onboard generator that can power an entire construction site in your truck...

  9. I see the North American truck industry is offering no diesel power in 1/2 ton trucks. Too bad!! It is amazing to me that the consumer in North America have no choice in power plants. I am so disappointed in our manufacturers. They should be ashamed of themselves.

  10. Comment disabled by moderators.

  11. Chevy holding on to its pushrod V-8 and V-6's reminds me of the old "flat heads for ever" folks. Technology proceeded forward, they gradually died off, and valve in block design faded into automotive history, except for use in lawn mowers. They also compensated for lack of power by improvements to air and fuel flow and displacement increases. Dual overhead cams are the way to go for power, fuel economy, and refinement. Chevy engines still feel like they're tearing themselves apart when pushed and sound still worse when a flowmaster exhaust is installed and the cylinders turn off and on.
    It's too bad because the trucks are beautiful, plush, and enjoyable till ya' start the motor. Stop advertising and spend some money in R and D.

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