In a desperate attempt to showcase the aging Silverado lineup over its rivals, GM touts cylinder deactivation with pushrods over multivalve per cylinder and downsizing with direct injection and turbocharging?
Wayne Gerdes - CleanMPG
- Aug 15, 2012
2013 Chevrolet Silverado – Pricing TBA and an at best 15/21 mpgUS city/highway using an aged design based on an original from almost 6 decades ago
GM’s fuel efficiency of its bread and butter 5.3L V8 engine in the latest 2013 Silverado continues to be enhanced with cylinder deactivation in low load operation.
Managers (not Engineers) developing the current Silverado sought the least expensive solution for improving the fuel economy while preserving its durability and lackluster
Jordan Lee, Global Chief Engineer for GM small block engines must have cringed when he was quoted by the PR group with the following:
“Rather than adding turbochargers or multi-valve cylinder heads to increase the power of smaller engines, we chose to keep the proven capability of our larger V8 truck engines, and save fuel by switching off half of the cylinders when they aren’t needed.”
A combination of simple hydraulic valves (read cheap) and software switch off the cylinders when the driver doesn’t need full power. When more power is needed, the system, called Active Fuel Management or AFM reengages the additional cylinders.
With the above, should Cruze ECO and Sonic owners with their modern designed 1.4L turbo’s including 4-valve per cylinder heads be concerned?
Additional diatribe that must be making Ford’s EcoBoost designers shake their heads included GM saying its 5.3L provides “V8 power and capability while offering up the best EPA fuel economy estimates of any V8 pickup.”
“Our 5.3-liter V-8 delivers EPA fuel economy estimates comparable to some competitors’ V6 engines.”
What they failed to provide was the performance AND fuel economy are both lacking by comparison to the latest modern V6 engine designs from Ford as shown in the following snap shot and spec description.
Ford’s 365 HP/420 lb-ft of torque 3.5L EcoBoost (16/22) vs. GM’s aging 315 HP/335 lb-ft. of torque 5.3L V8 (15/21 mpg) in a 620 ft. drag race.
The Silverado with the 4.3L V6 and 4.8L V8 using 4-speed ATs and the 5.3L V8 using a 6-speed AT was a group of old dogs competing with Ford’s pack of young wolves with their modern engine designs and 6-speed ATs. Not only was the older 5.3L V8 performance aspect proven subpar vs. the much more modern EcoBoost and Hemi onslaught hundreds of times, its EPA rated fuel economy is also significantly behind the times.
GM is stretching their entire PU truck engine lineup redesign at the expense of future owners
Even Ford’s naturally aspirated 302 HP/278 lb. ft. of torque 3.7L V6 mated to the modern 6-speed AT they provide provided sprint times just a fraction of a second off the Chevrolet 5.3L V8 for a lower cost, less HW thanks to its 4-valve per cylinder modern engine design vs. AFM all the while providing a respectable for a PU truck, EPA of 17/23 mpgUS city/highway compared to the 15/21 5.3L.
Later on in the PR, Lee added:
“As GM develops future vehicles, we will continue to draw on our company’s unsurpassed global powertrain portfolio, which includes direct injection, clean diesels, vehicle electrification, turbocharging, supercharging, and other technologies. But as with our current V-8 engines with Active Fuel Management, the starting point is always what’s the right solution for the customer and the way they use the vehicle.”
Can the following emoticon
describe this release any better?
GM, you can do much much better than this! Outdated 2-valve per cylinder pushrod engines were good 57 years ago when they were first designed but today with $4.00/gallon gasoline? Maybe that is why Ford sold 49,314 F-Series by comparison to the Silverado’s 28,972 and Sierra’s 11,105 vehicles purchased last month? This is the kind of thinking and product sinks corporations and you must do better
There was one highlight in this misguided release. According to Vincentric, the Silverado has the lowest total cost of ownership of any full-size pickup. I wonder what KBB says about that?