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Silverado with Active Fuel Management

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Test drove an '07 Silverado 1500 with the "Active Fuel Management" system on the 5.3 liter V8. Sales guy was saying that the truck is capable of mpg's in the low 20's on the open road when driving 60-65 mph, and other people here on this forum have made similar claims about the 5.3 liter on pre-AFM model years.

The AFM system works by disabling the lifters (via solenoids) on the valves of 4 of the 8 cylinders. Apparently this technology has been in use for a couple of years on other models, but how reliable is it? Would you trust GM to have worked out all the bugs, or will this feature prove to be problematic as the cars age and wear?

Could not find any bad news on AFM when I googled it, anyone here have any inside info? What do you guys think?

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The system was known as Displacement on Demand until just a few months ago, they changed it before release figuring the public wouldnt understand what the original name meant... so you might find more information by searching Displacement on Demand or DoD.

It really does work, and currently achieves gains of 10-15% better fuel mileage, they think with some fine tuning they can get those gains up to 40-50% in the next few years. Currently its only available on the 2007 5.3 small block (in ALL vehicles that motor is available in) and the 6.0 Max in the half ton. In the next few years it will be expanded into the other GM V8's and V6's, including performance cars like the new Camaro and GTO.

Its pretty early to tell exactly how reliable it is, but so far it doesnt seem to affect reliability or longevity of the motors at all. This system will get us 30mpg V8 trucks in the very near future.

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I'd be more interested in response times. Meaning, if you want to kick in the power or shift down a gear, how long before the other cylinders kick back in to give you the extra horsepower from the time you step on the gas? Is it noticeably longer than it would be without the fuel management?

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I'd be more interested in response times. Meaning, if you want to kick in the power or shift down a gear, how long before the other cylinders kick back in to give you the extra horsepower from the time you step on the gas? Is it noticeably longer than it would be without the fuel management?

There is a slight hesitation when you go from a steady speed to full throttle... less than a second but still not exactly instant. I'd imagine that will get better with more refinement too though.

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Would you trust GM to have worked out all the bugs
With GM's new 5 year/100,000 mile warranty, I wouldn't worry about it. Hopefully they have bought other people's products and examined the engineering on it. Honda's most excellent 3.5L V6 has the same technology where it shuts down 3 cylinders on the highway. Ford's V10 alternately shuts off half the cylinders in the event of coolant loss to provide a "limp home" mode.

In short, I wouldn't have a problem with it. In fact, I'm thinking about the 6.0L version myself.....

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