That's what I figured, but maybe someone else knows better?
I'm going with your evaluation, though.
No icons, no AFM.
So, Track, Manual, Z Modes disable AFM.
Question Question for the C8 guys (from a C7 guy)
- Thread starter Late Life Crisis
- Start date
I'm going with your evaluation, though.
No icons, no AFM.
So, Track, Manual, Z Modes disable AFM.
Crap, I forgot to check My Mode. 
I set the 4 modifiables to "Track" mode, but My Mode still shows V4/V8 icon, and changes depending on driving patterns.
I set the 4 modifiables to "Track" mode, but My Mode still shows V4/V8 icon, and changes depending on driving patterns.
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Where is the V4/V8 icon in your DIC in Manual Mode (not My Mode)?
Which quadrant, or what is it next to or near?
I'll check again.
OK, checked again, it does still show the V8 icon, but it never changes to V4 in Manual Mode.
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Today going down the highway I was monitoring things and was noticing the v4 indicator on when the TX was in 7th and because I have been varying speed in about 5 kph increments between 80 and 120 at one point approaching a hill gave it some gas v4 immediately disappeared and v8 shows . When I crested the hill and v4 appeared again I could both feel and slightly hear the difference as it reverted to 4 cylinders. No stereo on at the time. I think if you had the tunes cranked you wouldn’t hear it but would feel the slight difference if you had noticed it before.
I have never noticed/felt/heard the change, only see the DIC V4/V8 indicator, when it's there.
The average fuel economy number changes, too.
It is very subtle but if you watch for it you will notice it. Seems to be more noticeable when there is load on the motor when you ease off the throttle such as the situation I described above. I will watch for the fuel economy number. In what way does it change?
+ under V4, - under V8.
Taking your foot off the gas also disables v4
Perhaps so . Didn’t notice but will check tomorrow. Doesn’t seem to make sense on the face of it. I wonder if the behaviour of it has changed with successive model years…..
Not perhaps! FACT! Though it may not be with newer models. I can't speak to those.
OK !
I can verify that V4 on the dash turns off instantly when off throttle on my 2024.
This would be the desired effect as V4 would have no effect on gas mileage off throttle, as well as engine braking would also want to use all eight cylinders to be effective.
I am not sure why anyone would want to disable this function, except on the track which is why we have track mode, I can see no difference in performance with or without it activated for everyday driving or spirited driving in modes other than track. This technology has progressed greatly from the early 2000's.
Why disable it you wonder?> Well, because of the loud ugly sucking noise when it shifts into V4. That’s why!
It may “have progressed greatly from the early 2000’s”, but it still sucks.
Literally.
It may “have progressed greatly from the early 2000’s”, but it still sucks.
Literally.
Some hear / have a noise. Some (ME) don't. Weird!
I never hear anything at all when it swicthes either way. I have had two C8s and neither made noise.
DenisC8
Power User
Same here, 2 C8s no noise, no problems
See an audiologist......
I wear hearing aids. My hearing is better than 20/20 
- Thread starter
- #39
Still following as a C7 manual transmission owner. To answer 1st Vette’s question there was a significant issue with C7’s that was narrowed down to operating as a V4, with valve guides failing and I also believe some direct valve damage. Chevy, of course, refused to honour any warranty claims, at least initially. Quite a few C7 owners with the automatic transmission would keep the car in manual mode which was the only way to disable AFM unless you bought a Range device for the OBD port as a workaround.
But the only way to actually engage the cylinder deactivation “feature” on my M7 manual was to move the mode-selector into “Eco Mode”. I do assume that it would work to reduce fuel consumption on the C7 but I have no hankering to find out. Now the only thing that bugs me is the 1->4 skip shift (another GM fuel economy “benefit”), I’ve got the bypass harness to disable that but haven’t had the opportunity to install it yet.
LLC
That was the first thing I did on my Camaros. I actually made my own. It was just a resistor inline with the wires if memory serves. That drove me absolutely bonkers! Now you know why I am the way I am!
