2011 Chevy Silverado HD

Chevy revealed the 2011 Silverado HD at the Chicago Auto Show. Like Ford and Ram, Chevy puts the emphasis on revised diesel engine technology because new rules coming into play force all contenders to dramatically reduce emissions for 2011.  All employ urea-injection or what's become known as DEF (diesel emissions fluid) in the exhaust stream to achieve the goal, and all are boasting that they've not only cleaned up what comes out the tailpipe, but they've also upgraded performance and fuel efficiency. The most important change to the Silverado this year is the frame - going from a full-length C-channel design to a fully boxed frame with through-welded cross members. The frame is five times stiffer in twisting, 92% stiffer in bending, 20% stiffer in beaming and the front subframe is 125% stiffer by itself. The rear suspension has also been upgraded, now with offset leaf springs that have more spring behind the axle than ahead of it, which works to reduce axle hop under loaded take off.

Silverado HD Power and Handling

The '11 Chevy Silverado HD gets a significant upgrade under the hood with the fourth generation of the Duramax Diesel and Allison automatic transmission combination. The newest iteration of the Duramax shares about 40% of the parts with the last version with the remainder being slightly to significantly new. Compression ratio drops from 16.4:1 to 16.0:1, which in diesel world results in more power. The combustion chamber is fed by a new 30,000 PSI peizo-based fuel injector system. About 22 lbs was added to the block to improve block stiffness and improve NVH, and as a result the idle speed drops to about 900 RPM to reduce consumption. They've also significantly reduced the amount of EGR gasses injected back into the cylinder as part of a rework of their emissions strategy and added a bigger radiator to keep everything cool. Up front the truck maintains the double wishbone suspension with an adjustable torsion bar spring to level truck height with a plow attached. It has been upgraded with a second jounce bumper and a anti-roll bar with a longer lever arm for better control with a front load. The front brakes have also been upgraded with a set of massive 14" vented rotors clamped down on by stiffer calipers over a bigger swept area. Emissions are a big part of the change to the new Silverado. In order to meet the EPA requirements for NOx and particulate emissions, GM's installed a huge catalyst system and urea injector under the truck. Previously, trucks with particulate filters injected engine gasses into the combustion chamber (reducing power) and dumped fuel into the exhaust stream to burn the collected particulate, but in this case both of those actions have been moved downstream, outside of the engine, which allows it to breathe cleaner air and produce more power while reducing consumption.

2011 Silverado HD Diesel

Demanding dramatic reductions in both particulate (smoke) emissions and NOx (a 90 percent cut over what was previously allowed), the new emmissions rules force makers to use DEF injection and advanced catalytic converters. On the Chevy, there's a 10,000-mile supply of DEF carried in a tank behind the passenger-side wheel, with a filler underhood. Owners will get a warning light when there's 1,000-mile supply left--as it nears empty, speed will be restricted, first to 55 mph and then, when the DEF tank is empty, to only 4 mph. GM says it worked closely with the EPA to ensure that emissions requirements are met without the least inconvenience to owners of the trucks and a 1,000-mile warning seems ample enough even for cross-country haulers. When it arrives this summer, the 6.6-liter Duramax will offer what GM promises will be "significantly more torque and higher horsepower," from an engine that is now compatible with B20 biodiesel rather than only B5. Fuel efficiency will improve, internal changes enhance strength and durability, and there's an engine braking system that works in conjunction with the new Allison 1000 six-speed transmission to improve performance on steep grades. This latter is a far more sophisticated, electronically managed version of the engine-braking used by 18-wheelers--rather than a manually operated "jake brake" that alters the valve operation to increase engine braking, this system adjusts the variable-vane turbocharger to raise exhaust back pressure for a similar, but quieter result.

Design of the 2011 Silverado HD

While the new Silverado HD focuses primarily on improved powertrain and handling, it looks pretty much the same as it's predecessor. The only visual distinctions are more chrome on the front bumper, a slightly revised hood and "Duramax" hood badge, the end of 16" wheels at the bottom in favor or 17-inchers and the addition of 20" wheels at the top. It also gets hydraulic cabin mounts in the back. The Silverado 2500 and 3500 HD look very much like the 2010 models with only a new grille, bumper and hood to distinguish them--normally, you'd expect a complete restyle, but this modest approach was a cost-saving measure taken in light of GM's bankruptcy.

Conclusions

Despite minor appearance changes to the 2011 model, underneath the familiar Silverado sheetmetal, though, is an all-new truck, starting with a new frame. This includes 11 all-new frames to accommodate variations of cab and cargo box length, 4x4 and rwd drivetrains. For more details and the most up to date information, visit the official 2011 Silverado HD webpage. The frame is now fully boxed end-to-end and boasts uprated crossmembers to achieve a 92 percent improvement in bending stiffness, a 20 percent gain in torsional rigidity. While the demand for personal truck use has slightly faded, pickup trucks are still among the top selling vehicles in the U.S. However, the battle among Ford, GM and Chrysler continues in the heavy-duty pickup segment, where buyers need and use the extreme strength, traction, durability
and power. Contractors and those who tow and haul heavy loads routinely may not be immune to the economic downturn, but could find that improved fuel efficiency (and compatibility with B20 biodiesel) and capability make 2011 a good model year to consider replacing their biggest tools. Whether they choose Ford's new Power Stroke (built in-house for the first time), Ram's Cummins-built engine, or GM's new Duramax, they'll be using cleaner, quieter-running and more fuel efficient diesels than ever before. The new Silverado HD is ready for enormous undertakings. It starts with an available Duramax 6.6L Turbo-Diesel V8 that offers a maximum 397 horsepower and 765 lb.-ft. of torque, making it the most powerful heavy duty pickup on the planet.