Eco Mode
Thread Starter
Instructor
Joined: May 2008
Posts: 169
Likes: 36
From: China Spring TX
Eco Mode
I've tried to use 'search' for this question but couldn't find the answer. So, if its an old subject, please forgive me. When the V4 mode comes on, how are the cylinders chosen to deactivate? I assume it is not random since that could result in an uneven firing order. If it is the same 4 cyls. each time, that would result in uneven wear and ring groove issues. Once the V4 mode activates, do the same 4 cylinders stay deactivated until the next occurance of V4 mode or do they switch around from one group of 4 to another group of 4?
Burning Brakes
Joined: Feb 2010
Posts: 878
Likes: 61
From: Louisa, Ky
[QUOTE=ref772;1590520450]I've tried to use 'search' for this question
It also has a duty cycle of 10 min on and 1 min off. and has settings that are a lot more aggressive on automatics than stick shift cars. Factory did tweek the TPS Max from 50% on 14's to 40% on 15's. Per tables from HP Tuners.
It also has a duty cycle of 10 min on and 1 min off. and has settings that are a lot more aggressive on automatics than stick shift cars. Factory did tweek the TPS Max from 50% on 14's to 40% on 15's. Per tables from HP Tuners.
Moderator
Joined: Feb 2006
Posts: 39,063
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From: DFW Area TX
<p></p><p> </p><p>Active Fuel Management (AFM), which shuts down the LT1’s firing cylinders from eight to four by disabling the valves to the cylinders, also brings the efficiency of the 6.2L pushrod motor to never-before-seen heights. When AFM commences, the engine turns the 6.2L V8 into a 3.1L V4, shutting down cylinders 1, 4, 6 and 7, and firing only cylinders 8, 2, 5 and 3 in that order. Otherwise, the complete firing order is 1, 8, 7, 2, 6, 5, 4, 3.</p>
Last edited by Zymurgy; Sep 18, 2015 at 02:07 PM.
Burning Brakes
Joined: Feb 2010
Posts: 878
Likes: 61
From: Louisa, Ky
The system is allowed to engage in 3rd gear and up on the auto and 4th for the stick when eco is selected. All modes for the auto except manual paddle shift. It goes back to V8 quicker when TPS max percentage is lowered.
Le Mans Master
Joined: Sep 2012
Posts: 7,146
Likes: 1,940
From: Hagerstown MD
St. Jude Donor '15-'16,'18
I've tried a couple times to measure the difference in mileage when running in Eco, Tour and Sport modes. Used the same stretch of highway for each run but the temps were slightly different. Car was loaded the same and speeds were the same. Very little difference in mileage. What exactly does Eco mode do? Is it supposed to increase the amount of time spent running in V4 mode?
Burning Brakes
Joined: May 2010
Posts: 891
Likes: 303
From: Red Bank NJ
I've tried a couple times to measure the difference in mileage when running in Eco, Tour and Sport modes. Used the same stretch of highway for each run but the temps were slightly different. Car was loaded the same and speeds were the same. Very little difference in mileage. What exactly does Eco mode do? Is it supposed to increase the amount of time spent running in V4 mode?
IN reality, most people arent seeing very much, if any difference in MPG.
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Burning Brakes
Joined: Feb 2010
Posts: 878
Likes: 61
From: Louisa, Ky
Advanced
Joined: Nov 2005
Posts: 89
Likes: 2
Is Eco the only mode that allows 4 cylinder operation? The reason I ask is that I'm thinking that I never want the engine to run on 4 cylinders. I know that GM had to beef-up the drive train of the C7 to deal with vibrations induced by 4 cylinder operation. I'm not sure I really want to stress the drive train if I can avoid it. Is this concern silly of me?
Safety Car
Joined: Sep 2011
Posts: 3,913
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From: Cary NC
That is only true of the manual transmission. With an automatic transmission, it can go into V4 in any driving mode except Track.
Burning Brakes
Joined: Apr 2015
Posts: 755
Likes: 19
From: San Antonio TX
And when in eco mode, it is very obvious that the car goes into V4 mode more often than when in tour, or sport.
Burning Brakes
Joined: May 2010
Posts: 891
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From: Red Bank NJ
Burning Brakes
Joined: Feb 2010
Posts: 878
Likes: 61
From: Louisa, Ky
Burning Brakes
Joined: Feb 2010
Posts: 878
Likes: 61
From: Louisa, Ky
Melting Slicks
Joined: Mar 2013
Posts: 3,104
Likes: 626
From: Baton Rouge LA
Here are a couple of write-ups on this subject:
Write-up 1
Write-up 2
My A8 goes into V4 in any mode, even Track. The Driving Mode chart in the manual backs this up.
I agree with you that mileage is noticeably better in V4 mode, close to the 2-3mpg claim made by GM in my car, but I haven't seen any difference at all on AFM operation in Eco, Tour, or Sport. My mileage has been as good in Sport (my choice for the past two months) as it was in Eco, where I had it set most of the time before that. Mine's an A8, BTW.
OTOH, the manual states that Weather, Tour, Sport, and Track all use "Normal" AFM operation, but Eco uses "Eco," so there must be an AFM difference in Eco driving mode compared to the others.
Write-up 1
Write-up 2
OTOH, the manual states that Weather, Tour, Sport, and Track all use "Normal" AFM operation, but Eco uses "Eco," so there must be an AFM difference in Eco driving mode compared to the others.
Last edited by iclick; Sep 18, 2015 at 05:05 PM.
Racer
Joined: Apr 2014
Posts: 401
Likes: 59
From: Houston
I don't understand the hate for AFM - it is only in V4 mode when there is little or no load on the engine, as soon as you need more power it instantly goes back to V8...anything that helps me visit a gas station a little less is fine with me.
Safety Car
Joined: Jul 2001
Posts: 4,661
Likes: 67
From: Ocean Springs MS
Well, everyone's entitled to an opinion. OTH, I've been driving an Avalanche with AFM for 9 years with no problems. The two C7s have 17k and 4k. Both autos, so they go into V4 mode regularly, although the Z does so lots less than the Stingray. No engine problems on either of them.