Interesting bit of tech in the new GM V8s to increase fuel economy. These definitely aren't your traditional V8s with all of the added moving parts and computers needed to operate them. It is also interesting how each truck make has different ways to increase/decrease the effective displacement of their truck engines to conserve fuel. GM and Ram's approach is to start out with a larger displacement engine and deactivate cylinders to make it a lower displacement when power is not needed while Ford's Ecoboost approach is to start with lower displacement and add turbos to it to increase it's effective displacement when more power is needed.2019 Chevy, GMC Trucks Get Smarter Fuel-Saving Cylinder Deactivation

Better than the original try with the Cadillac engines.

1995brave wrote:Better than the original try with the Cadillac engines.Yeah, that was one idea that was way ahead of it's time and did not have the technology to support it. Thankfully computer processing has vastly increased in speed and multitasking since then that it can handle the fraction of a second timing events needed for today's engines.

it would be interesting how this would work on a diesel. the duramax has way more power and torque than needed in most driving, especially in town. and with direct injection it would be pretty easy to deactivate cylinder(s).

Had a friend that had a ‘80 something Chevy that had “cylinder deactivation”, the problem was....all eight (8) were “deactivated “! :B

Don't know what the difference is but a good friend's 2017 GMC Denali SUV has that feature. Or at least similar. I think it deactivates two cylinders when cruising at highway speeds and not under any undue load. I can not tell when it changes back and forth when I ride with him.

2019 GM trucks get smarter fuel-saving cylinder deactivation

1995brave
Nomad
Jan 25, 2018
Better than the original try with the Cadillac engines.
ShinerBock
Explorer
Jan 25, 2018
1995brave wrote:
Better than the original try with the Cadillac engines.

Yeah, that was one idea that was way ahead of it's time and did not have the technology to support it. Thankfully computer processing has vastly increased in speed and multitasking since then that it can handle the fraction of a second timing events needed for today's engines.
ktmrfs
Explorer II
Jan 25, 2018
it would be interesting how this would work on a diesel. the duramax has way more power and torque than needed in most driving, especially in town. and with direct injection it would be pretty easy to deactivate cylinder(s).
memtb
Explorer
Jan 25, 2018
Had a friend that had a ‘80 something Chevy that had “cylinder deactivation”, the problem was....all eight (8) were “deactivated “! :B
BB_TX
Nomad
Jan 25, 2018
Don't know what the difference is but a good friend's 2017 GMC Denali SUV has that feature. Or at least similar. I think it deactivates two cylinders when cruising at highway speeds and not under any undue load. I can not tell when it changes back and forth when I ride with him.
ShinerBock
Explorer
Jan 25, 2018
BB_TX wrote:
Don't know what the difference is but a good friend's 2017 GMC Denali SUV has that feature. Or at least similar. I think it deactivates two cylinders when cruising at highway speeds and not under any undue load. I can not tell when it changes back and forth when I ride with him.

The difference between this system and the current one your friend has that the new system can deactivate any cylinder at any time depending on load requirements rather than just four cylinders.
SoundGuy
Explorer
Jan 25, 2018
ShinerBock wrote:
Interesting bit of tech in the new GM V8s to increase fuel economy.

I'll believe it when I see "it", meaning any improvement in fuel mileage and/or performance. :( My 2012 Silvy has fuel management and honestly I see no advantage at all, in fact the truck gets slightly less fuel mileage overall than did my previous 2006 Silvy and 2005 Avalanche, neither of which had any sort of cylinder deactivation system but both of which ran the same 5.3L engine and same 3.42 axle even though they also both had the older wide ratio 4-spd transmission that supposedly wasn't as efficient as the narrow ratio 6-spd I have in my current '12. I see this stuff more as fluff for sales brochures, not an actual on road performance improvement for owners.
Chuck_thehammer
Explorer
Jan 25, 2018
Cadillac 8-6-4......

and went on fire,, at the stop light after being on the freeway...

that is a smell you do NOT want to remember...
spoon059
Explorer II
Jan 25, 2018
ShinerBock wrote:
The difference between this system and the current one your friend has that the new system can deactivate any cylinder at any time depending on load requirements rather than just four cylinders.

I didn't understand some of the article, but I think this is a pretty good idea. The problems that I have seen with this cylinder deactivation is that dropping 4 cylinders leads to that clunky feeling and odd sound. Having the ability to just drop 2 cylinders, apparently in random order, should work pretty well in a heavier truck. I'm curious to see how this technology works int he real world. 15% increase in fuel economy (maybe 3 mpgs) might be worthwhile... depending upon the cost and complex nature of the engine. Hope they maintain reliability at the same time.
IdaD
Explorer
Jan 25, 2018
Our Pilot as cylinder deactivation and it's pretty seamless and hasn't given us any trouble in 8 years of ownership. I'm not sure it's too effective, though - that thing is a gas hog.