Disable 4 cylinder mode
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3,718 Posts
WHY?? Have you driven a C7 auto? The change from 4 to 8 is seamless. The 8 is there before you think you need it!!
not correct...the afm is on all the time in every mode in an A6 (noone knows abouot the a8 yet)...you must be in MANUAL to kil AFM with an A6...
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3,718 Posts
Thank you. Stand corrected. For a moment I got it confused with NPP. I am going to modify my post.
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Are you opposed to saving gas or not satisfied with your AFM operation? You need 8 cyl full time? What is better for your engine? How many miles on your C7? Come on indytoatl more content.
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24 Posts
When in four cylinder mode, does it vary the all cylinders equally for even wear, or does it always fire the same four?
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4,656 Posts
I believe it's Always the same 4 and the wear issue has been beaten to death but no one really knows how the new generation motors will hold up.
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993 Posts
Same 4.
I had an '89 Vette way back when and I loved the rumble of the engine and exhaust. I have another 4 cylinder in my garage if I want to save on gas.
I love the car but this is the only thing I wish they had made as an on/off switch.
I love the car but this is the only thing I wish they had made as an on/off switch.
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3,672 Posts
They did give us an on/off with the 7 speed - ECO Mode.
We can only speculate why they didn't do the same with the auto trans. My guess is to help meet CAFE fuel economy.
Still, even when on 4 cylinders, the C7 has more power than many vehicles on the road.
"In 1987, the average vehicle had about 118 horsepower, according to the Environmental Protection Agency. By 1998, it was up to 171. And in 2008, horsepower averaged 222. Average zero-to-60-mph times fell from 14.1 seconds in 1987 to 9.6 seconds by 2008. Today, a few production cars can hit 60 mph in half that time." http://blog.nwautos.com/2011/04/tod..._ever_--_but_how_much_can_drivers_handle.html
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36 Posts
I have AFM (AKA DoD) disabled on my Z51 with NPP and A6. The Diablo tuner will allow you to modify and disable it if you wish. I didn't like the car going silent whenever I got over 25 MPH.
My observation from things I've read on this, and other, forums is that there seems to be a correlation between the AFM feature and certain problems (e.g. torque tube rattle, belt tensioner). Therefore, I don't use it. I still manage to get 26-27 mpg on the highway in 6th gear. Good enough for me.
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504 Posts
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504 Posts
The G8 crowd experience lifter failures with the AFM lifters. They were supposedly updated at one point but not sure if they were truly improved. With LT1 being a new animal, it's possible that GM learned from the G8 failures and has improved things by now. Let's hope at least. If the lifters are of concern, you can always remove the hardware and install more aggressive cam while doing so. Just takes time and money...
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631 Posts
All L99 based GM V8's have this as well in the Gen5 Camaro, and the issues related to it (and the GM trucks) and the issues are well documented. I cant see any part of AFM/DOD that GM has changed from the previous generation to the DI based...all components appear to be the same, and yes I can feel it...very noticeable and I hate it, and the failures I see when tearing into them to fix failures, or more commonly, convert to non AFM/DOD. Have boxes of AFM lifters here through the years:
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You can tune out the activation or for longevity, especially those running at sustained high RPM's, pull the heads and replace the AFM/DOD lifters with conventionals and the valley cover (the solenoids are fed through upright cast supports from the Cam oil passages so plugging the top ends is recommended to avoid pressure bleed-off). Then you have eliminated the issue properly. There are some excellent DOD performance ground cams available, but the added lift and duration makes the DOD lifters more unstable at high RPM's as only the spring is maintaining lifter roller with the cam lobe and the instability hammers the roller/needle bearings/cam lobes pretty hard and that's where we see failures.
You can tune out the activation or for longevity, especially those running at sustained high RPM's, pull the heads and replace the AFM/DOD lifters with conventionals and the valley cover (the solenoids are fed through upright cast supports from the Cam oil passages so plugging the top ends is recommended to avoid pressure bleed-off). Then you have eliminated the issue properly. There are some excellent DOD performance ground cams available, but the added lift and duration makes the DOD lifters more unstable at high RPM's as only the spring is maintaining lifter roller with the cam lobe and the instability hammers the roller/needle bearings/cam lobes pretty hard and that's where we see failures.
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65 Posts
Feels pretty seamless to me. Never thought about any additional wear though...
LA
LA
When you say seamless, does that mean you do not notice when the car shifts in and out of 4 cylinder mode? If so, there must be something wrong with my vehicle.
The car loses so much power it's hard to climb a hill until I give it gas and it goes back into 8 cylinders. It's been that way since I first bought it.
I have an automatic LT1
Take it in...the AFM is not noticeable at all to 98 pct of those that own it.....
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