2012 Chevrolet Avalanche ..lt..4x4....no Accident History...save Big Time !!!!! on 2040-cars

Auto blog

2014 Chevrolet Silverado and GMC Sierra debut all-new designs, three new engines

General Motors has finally dropped the curtain on the 2014 Chevrolet Silverado and 2014 GMC Sierra. Both trucks have undergone substantial revisions with updated versions of the company's 4.3-liter V6, 5.3-liter V8 and 6.2-liter V8 engines. In a shot across the bows of both Ford and Chrysler, GM says it won't use a V6 engine adapted from passenger car applications. Instead, it developed the 4.3-liter engine based on its proven truck-duty architecture.
All three mills will boast direct injection fuel systems as well as a new cylinder head design. Combined with a revised piston, the new engines feature a smaller combustion chamber with a compression ratio of 11:1 or higher depending on the application. Cylinder deactivation and continuously variable valve timing are all part of the recipe, and each engine is paired with a six-speed automatic transmission with auto grade breaking. So far, no fuel economy or horsepower figures have been released, though GM says the new engines will best their predecessors in both areas.
Outside, the trucks feature a number of enhancements to reduce drag and wind noise, and GM claims both the Silverado and Sierra will offer buyers some of the quietest cabins in the class. Extended cab models now feature front-hinged rear doors to allow easier access to the back passenger area, and Crew Cab buyers can now select between a five-foot, eight-inch bed or a six-foot, six-inch bed. Buyers with a mind toward going off road will also rejoice in the return of the Z71 package, complete with Rancho shocks, front tow hooks and additional under-body protection.

2016 Chevy Volt arrives with 50-mile EV range, 41 mpg [w/ video]

Let's start with the numbers. The 2016 Chevy Volt will have an all-electric range of 50 miles from a new, 18.4-kWh lithium battery. It will get 41 miles per gallon (combined) once the battery runs dry and have 102 MPGe. Oh, and it has five seats, sort of. To compare, today's four-seat 2015 Volt has a 38-mile range from a 17.1-kWh battery in a powertrain that offers 37 mpg and 98 MPGe. So, across the board, there are notable improvements. Now that that's out of the way, let's talk story. General Motors will unveil the new Volt at the Detroit Auto Show later today, but it's been talking about how this new version – the first major plug-in hybrid vehicle to get a serious redo in the modern era – was crafted with reams and reams of data from first-gen Volt customers. At a preview event for journalists last week, GM executive chief engineer Pam Fletcher told Autoblog that these owners "gave us the recipe" to make the second-gen model. At the top of the request list was more range (check), more "fun-to-drive" behavior (check?) and a smoother and quieter experience (we'll assume a check here, given that the new 1.5-liter four-cylinder – the first North American application of this new engine family – should offer more power with less noise than the previous 1.4-liter, four-cylinder powerplant). Other customer-driven changes in the new Volt include a different place to store the charging cable (in the side of the trunk instead of under the load floor) and a new brake system with improved blended regenerative braking feel as well as driver-selectable regen levels. The requested 50-mile range comes from a new, lighter battery that has increased capacity from fewer cells (192 vs. 288) and a simplified control architecture. Along with the new battery, the electric drive unit is a two-motor deal that is up to 12 percent more efficient and 100 pounds lighter, while also being "tremendously smaller," notes Fletcher. It offers 294 pound-feet of torque and a maximum 149 horsepower of "motoring power" delivered to the wheels. GM says it has worked hard to reduced the amount of rare earth materials in these motors, and one of them doesn't use any at all. The new powertrain offers improved acceleration times, as well. The 2016 Volt can go from 0 to 60 miles per hour in 8.4 seconds, a seven-percent improvement, while the 0-30 mph time has been improved by 19 percent, down to 2.6 seconds. The new Volt is more conventional looking, but certainly not completely ordinary.

Is the skill of rev matching being lost to computers?

If the ability to drive a vehicle equipped with a manual gearbox is becoming a lost art, then the skill of being able to match revs on downshifts is the stuff they would teach at the automotive equivalent of the Shaolin Temple. The usefulness of rev matching in street driving is limited most of the time – aside from sounding cool and impressing your friends. But out on a race track or the occasional fast, windy road, its benefits are abundantly clear. While in motion, the engine speed and wheel speed of a vehicle with a manual transmission are kept in sync when the clutch is engaged (i.e. when the clutch pedal is not being pressed down). However, when changing gear, that mechanical link is severed briefly, and the synchronization between the motor and wheels is broken. When upshifting during acceleration, this isn't much of an issue, as there's typically not a huge disparity between engine speed and wheel speed as a car accelerates. Rev-matching downshifts is the stuff they would teach at the automotive equivalent of the Shaolin Temple. But when slowing down and downshifting – as you might do when approaching a corner at a high rate of speed – that gap of time caused by the disengagement of the clutch from the engine causes the revs to drop. Without bringing up the revs somehow to help the engine speed match the wheel speed in the gear you're about to use, you'll typically get a sudden jolt when re-engaging the clutch as physics brings everything back into sync. That jolt can be a big problem when you're moving along swiftly, causing instability or even a loss of traction, particularly in rear-wheel-drive cars. So the point of rev matching is to blip the throttle simultaneously as you downshift gears in order to bring the engine speed to a closer match with the wheel speed before you re-engage the clutch in that lower gear, in turn providing a much smoother downshift. When braking is thrown in, you get heel-toe downshifting, which involves some dexterity to use all three pedals at the same time with just two feet – clutch in, slow the car while revving, clutch out. However, even if you're aware of heel-toe technique and the basic elements of how to perform a rev match, perfecting it to the point of making it useful can be difficult.