Cylinder Deactivation in Chevy 6 Liter Question

[BobsArmory]

While trying different routes for my daily commute to and from work I found that I can take the "service road" into work instead of the High Way. This route saves me 2 miles on the trip each way AND because of the reduced speed 55 mph vs. 70 mph I gain a whopping 20% on my fuel mileage in my 2009 Chevy 1500 4x4 with a 6 liter V-8.

My question is. If I run my truck at 55 mph the engine will only be running on 4 pistons for most of the commute (18.8 miles each way). Are there any issues that might pop up when running in deactivation mode almost all the time?

 

[MBS500]

Honda engines with similar system that were driven by soccer moms had sludge and varnish troubles.
Take it to the hwy twice a week I would say.

 

[SteveSRT8]

Nope. We have several of these in service vans and they run great. I have been able to 'lightfoot' them and keep them in 4 cylinder mode up to over 80 mph!

Sure saves the fuel, eh?

 

[JHZR2]

Originally Posted By: MBS500
Honda engines with similar system that were driven by soccer moms had sludge and varnish troubles.
Take it to the hwy twice a week I would say.


Are you 120% sure the two things correlate? I kind of doubt it actually.

 

[RF Overlord]

Does the Chevy deactivate the same 4 cylinders every time? I think the problem with the Honda system is that it deactivates one whole bank each time and it's the same bank every time so one side of the motor gets very hot and the other side stays cooler.

Hopefully the Chevy version at least splits the 4 cylinders between both banks.

 

[SwampSurvivor]

Originally Posted By: RF Overlord
Does the Chevy deactivate the same 4 cylinders every time? I think the problem with the Honda system is that it deactivates one whole bank each time and it's the same bank every time so one side of the motor gets very hot and the other side stays cooler.

Hopefully the Chevy version at least splits the 4 cylinders between both banks.


At part throttle cruise, the 3 cylinders that are working shouldn't generate too much heat. If you need that much power, it would activate the other 3 cylinders.

 

[MBS500]

Originally Posted By: JHZR2
Originally Posted By: MBS500
Honda engines with similar system that were driven by soccer moms had sludge and varnish troubles.
Take it to the hwy twice a week I would say.


Are you 120% sure the two things correlate? I kind of doubt it actually.

No not 120%, but I remeber engines that Trav took apart which had many short trips. And as mentioned above , one bank was in much much worse condition.

 

[yonyon]

Originally Posted By: RF Overlord
Hopefully the Chevy version at least splits the 4 cylinders between both banks.


It would be silly not to. On a V6 the firing order is odd-even repeating O-E-O-E-O-E. On an eight you might have something more like O-E-O-E-E-O-E-O so if you skip every other cylinder you get two odds and two evens which means two from each bank. If they just shut down one bank instead of skipping every other cylinder it would feel awfully rough.

It's too bad they don't let you press a button and ask it to idle in 4-cyl mode. I'd bet that with dual exhaust that would sound musical.

 

[GMBoy]

I assume you have the L76 6.0L engine and not the hybrid 6.0L.

With that - you are fine...they don't stay in 4cyl mode very much anyhow as anything less than featherlight will kick it back to V8 mode. I have reviewed many engine cal files for all the truck engines and they have safety measures built in...so don't worry and Enjoy the economy.

(Oh and greetings to you Bob - a fellow GM employee!)