GM Dynamic Skip Fire

[wirelessF]

http://www.thetruthaboutcars.com/2015/09/cylinder-deactivation-drop-corvette-2-cylinders
http://www.autonews.com/article/20150915...er-deactivation

GM 8-6-4-2? AFM 2.0? With GM grasping onto the pushrod V8 GM has developed a new cylinder deactivation tech that can deactivate up to 6 cylinders. Testing was done with a current GMC with the 6.2L which showed 21% improvement in fuel economy.

 

[OneEyeJack]

Another reason that certain cars should never be owned beyond the factory warranty. Add this to the list.

 

[mjoekingz28]

IMO just not worth it. If you are that desperate to save on petroleum, get an electric car.

And, I keep being informed they burn oil.......that added to the costs of engineering and implementing the devices necessary to make it work.....then, the potential for problems, far far outweigh a marginal highway flat ground non-towing low speed no headwind AC off scenario.

 

[hattaresguy]

Its not worth if if you want to burn less fuel don't buy a 400hp truck.

 

[stchman]

I have had AFM(Active Fuel Management) on my last two Silverados and it performed as it should. Neither 5.3L used oil excessively and if I had to guess I got maybe 1.5MPG gain.

 

[spackard]

Gasoline engines use a flap in the throttle body to regulate the amount of air that enters the intake manifold. The flap’s usual position is nearly closed, causing the engine to work harder to ingest air. DSF keeps the throttle flap almost fully open and controls the engine’s power by varying the numbers of cylinders that fire.

I like the idea. I think there's a possibility for fueling and firing different combinations of pistons, like flashing xmas lights.

 

[BobsArmory]

8,000 mile OCI on my AFM Silverado 6 liter. Guess how much oil it uses? Yep, 1/2 quart of M1 EP per 8,000 miles

 

[Nate1979]

GM AFM is horrible, clunky, not seamless at all. Horrible programming make them drive like a dog when in 4 cylinder mode. This is why many choose to turn it off.

Hopefully they can make it better than the current version. Though I hear the latest gen (2014+) is better than my 2012 (which is terrible).

 

[OVERKILL]

Chrysler's version is surprisingly well implemented

 

[Clevy]

Originally Posted By: OVERKILL
Chrysler's version is surprisingly well implemented

I agree. If it wasn't for the deeper exhaust note I wouldn't even be able to tell 4 cylinders shut off.

I thought chev had fixed the issues though on newer models

 

[sciphi]

We'll see how this goes. Every once in a while GM has a really off the wall idea that works out well. Let's hope this is one of them.

 

[Clevy]

I just read the articles. I really like the idea,especially that the shut of cylinders vary and aren't always the same ones.

It's complicated though id rather not be the beta tester,unless of course it came for free

 

[Lightninrod]

Originally Posted By: OVERKILL
Chrysler's version is surprisingly well implemented

So far, so good too on my 2013 Jeep Grand Cherokee Overland V8.

Dan

 

[VNTS]

Originally Posted By: OVERKILL
Chrysler's version is surprisingly well implemented

Yes it is, excellent seamless system on my Grand Cherokee, avg 23 mpg on highway.

If they can shutdown more cylinders during flat highway cruising, sounds good to me.

 

[hattaresguy]

That I don't get Chrysler's cylinder shut down is seamless, the only way I know its working is the little ECO light comes on.

 

[sciphi]

It takes some surprisingly low HP output to cruise on flat ground at about 60 mph. So shutting down all but two cylinders makes sense for a power-dense engine like a LS or LT series V8 when it's lightly loaded on a grocery run. Then all 8 cylinders when hauling the boat up the ramp or hauling the 5th wheel up to the hilltop campsite.

 

[Clevy]

Originally Posted By: sciphi
It takes some surprisingly low HP output to cruise on flat ground at about 60 mph. So shutting down all but two cylinders makes sense for a power-dense engine like a LS or LT series V8 when it's lightly loaded on a grocery run. Then all 8 cylinders when hauling the boat up the ramp or hauling the 5th wheel up to the hilltop campsite.



Not quite. To maintain highway speeds doesn't take much hp however it takes all of them to get the vehicle moving from a dead stop.
So it needs all 8 to achieve cruising speed but once in motion it doesn't take much to keep it there