C8 AFM Disable?
3rd Gear
Joined: Nov 2019
Posts: 3
Likes: 0
It’d be nice to be able to disable AFM in every mode rather than just Track and Z-Mode Track. I notice mine switch over most of the time. It can be seamless at times but I wouldn’t say that is the norm in my experience.
Would agree that seamless to one person isn’t to another.
Would agree that seamless to one person isn’t to another.
Instructor
Joined: Nov 2022
Posts: 110
Likes: 43
1) I can feel it
2) I can hear it. (non NPP exhaust)
3) I question what, if any benefit it has. The car get's good mileage on the highway because it has an 8 speed trans.
Just my opinion ...
My Silverado lost maybe a .5 mile to a mile per gallon tops, going from AFM to having it disabled.
2) I can hear it. (non NPP exhaust)
3) I question what, if any benefit it has. The car get's good mileage on the highway because it has an 8 speed trans.
Just my opinion ...
My Silverado lost maybe a .5 mile to a mile per gallon tops, going from AFM to having it disabled.
1. I can't hear the change over
2. I can't feel the change over
As I watch the dash as it switches back and forth, I don't notice any obvious changes (other than the indicator.)
It must be something with people's individual C8, (or imagination????)
Drifting
Joined: May 2002
Posts: 1,477
Likes: 1,104
From: Nashville TN
E-Ray, 3LZ, ZER, LIFT
Joined: Sep 2007
Posts: 35,018
Likes: 12,399
From: NE South Carolina
"Create a device that simply overrides that LED and you'll make a mint."
Assume you you mean can't tell it's activated like mine now 3 years old! The old Click & Clack the Tappet Brothers solution would work. Just put a small piece of black electrical tape over the V4 indicator!
Would work for mine as have zero noise or sneezing sound etc. Been the same all 3 years!
Last edited by JerryU; Sep 8, 2023 at 01:29 PM.
Pro
Joined: Feb 2018
Posts: 611
Likes: 415
From: Texas
I have a 2023 Z51 with 1500 miles and I definitely hear it and feel it. Going to ping the dealership as it’s consistently switching and driving me CRAZY. I also don't what to have to drive around all the time in Manual mode or Z-mode. If it was truly seamless i wouldn't care
Let your dealer take yours for a drive, as it seems to be specific to only certain cars.
Race Director
Joined: Sep 2016
Posts: 13,180
Likes: 10,528
Drifting
Joined: May 2002
Posts: 1,477
Likes: 1,104
From: Nashville TN
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Instructor
Joined: Jan 2021
Posts: 156
Likes: 242
From: DFW
Its fairly well known that the AFM or DFM that GM produces is/was a flawed design with the Lifter Failures. I've had a Silverado with the lifter failure and my buddy Mike aka Brink of Speed had the issue with his C7 Z06. Lets hope its improved in the C8. I wouldn't mind it going into V4 if I could trust it, but with the reputation of GM's lifter failures and my past experience and many others I just don't. The sad thing is running it in V8 mode, may not help!
Race Director
Joined: Sep 2016
Posts: 13,180
Likes: 10,528
Its fairly well known that the AFM or DFM that GM produces is/was a flawed design with the Lifter Failures. I've had a Silverado with the lifter failure and my buddy Mike aka Brink of Speed had the issue with his C7 Z06. Lets hope its improved in the C8. I wouldn't mind it going into V4 if I could trust it, but with the reputation of GM's lifter failures and my past experience and many others I just don't. The sad thing is running it in V8 mode, may not help!
https://www.youtube.com/watch?v=M1BgCsxFdPM&t=5s
https://www.youtube.com/watch?v=M1BgCsxFdPM&t=5s
Melting Slicks
Joined: Dec 2006
Posts: 2,694
Likes: 106
That is true, and that brings me to my question: Are you always stressing the same 4 cylinders more than the idle 4? Or the ECU is smart enough to vary which cylinders are powering the vehicle, to rotate them? If always the same, just for that reason I wouldn't like it activated at all. I almost always drive my paddle vehicles in manual mode, so that'd be my preferred method of circumventing AFM. But don't like the unnecessary complication of having that crap on my car, but guess you have to look at it as it saved us some moolah in possible gas guzzler fees.
Race Director
Joined: Mar 2007
Posts: 11,424
Likes: 8,575
That is true, and that brings me to my question: Are you always stressing the same 4 cylinders more than the idle 4? Or the ECU is smart enough to vary which cylinders are powering the vehicle, to rotate them? If always the same, just for that reason I wouldn't like it activated at all. I almost always drive my paddle vehicles in manual mode, so that'd be my preferred method of circumventing AFM. But don't like the unnecessary complication of having that crap on my car, but guess you have to look at it as it saved us some moolah in possible gas guzzler fees.
Race Director
Joined: Sep 2016
Posts: 13,180
Likes: 10,528
[QUOTE=Revmanii;. You still have to produce the same amount of energy to go the distance, whether you burn it in 4, or 8.[/QUOTE]
As Tadge has explained, and has been posted here repeatedly, in 4 cyl mode the engine is operating with the throttle plate open more, which means less restriction, which means more efficiency.
Aside from that, your statement is obviously false. A Honda Civic uses far less energy to go the same distance at the same speed as a Corvette, even though the Corvette probably has less drag and probably cruises at lower rpm.
As Tadge has explained, and has been posted here repeatedly, in 4 cyl mode the engine is operating with the throttle plate open more, which means less restriction, which means more efficiency.
Aside from that, your statement is obviously false. A Honda Civic uses far less energy to go the same distance at the same speed as a Corvette, even though the Corvette probably has less drag and probably cruises at lower rpm.
Le Mans Master
Joined: Aug 2015
Posts: 8,243
Likes: 4,618
From: Southwest Florida
I too only drive in manual for several reasons
1) I love paddle shifting it makes me feel more connected to the car
2) I tried driving in auto (D) after a 1000 miles but it kept going in and out of V4.
3) Still feel snake.bit from my C7 V4 mode experience.
1) I love paddle shifting it makes me feel more connected to the car
2) I tried driving in auto (D) after a 1000 miles but it kept going in and out of V4.
3) Still feel snake.bit from my C7 V4 mode experience.
Race Director
Joined: Mar 2007
Posts: 11,424
Likes: 8,575
Because you've seen and read testing that shows the improved gas mileage you get with AFM? I've yet to see anything that shows more than a mile per gallon benefit in the best circumstances. You still have to produce the same amount of energy to go the distance, whether you burn it in 4, or 8.
As Tadge has explained, and has been posted here repeatedly, in 4 cyl mode the engine is operating with the throttle plate open more, which means less restriction, which means more efficiency.
Aside from that, your statement is obviously false. A Honda Civic uses far less energy to go the same distance at the same speed as a Corvette, even though the Corvette probably has less drag and probably cruises at lower rpm.
Aside from that, your statement is obviously false. A Honda Civic uses far less energy to go the same distance at the same speed as a Corvette, even though the Corvette probably has less drag and probably cruises at lower rpm.
As engines incorporate other technology to increase volumetric efficiency - such as variable valve timing (which the C8 has), or turbocharging (that paper I mentioned in post 27 lists others), the improvement from Cylinder Deactivation gets a lots smaller - as you can also see in the table in post 27.
E-Ray, 3LZ, ZER, LIFT
Joined: Sep 2007
Posts: 35,018
Likes: 12,399
From: NE South Carolina
That is true, and that brings me to my question: Are you always stressing the same 4 cylinders more than the idle 4? Or the ECU is smart enough to vary which cylinders are powering the vehicle, to rotate them? If always the same, just for that reason I wouldn't like it activated at all. I almost always drive my paddle vehicles in manual mode, so that'd be my preferred method of circumventing AFM. But don't like the unnecessary complication of having that crap on my car, but guess you have to look at it as it saved us some moolah in possible gas guzzler fees.
You don't appear to get the picture of what is happing! The folks pushing zero CO2 emissions are NOT going to Rich, Corvette, Ferrari etc owner's just pay money to pollute the earth with CO2. The 2012 EPA plan to have Corvettes require ~39 mpg by 2025 was a Prohibitive Fine of the manufacture if the EPA set goals by car family was not met! (That plan was stopped with a Pen BUT the new Pen reinstated one with 10% lower requirement in 2026 BUT no details. That will be announced January 2025! NOPE can't just pay money and destroy the world!
Last edited by JerryU; Sep 24, 2023 at 09:44 AM.
Race Director
Joined: Mar 2007
Posts: 11,424
Likes: 8,575
That is true, and that brings me to my question: Are you always stressing the same 4 cylinders more than the idle 4? Or the ECU is smart enough to vary which cylinders are powering the vehicle, to rotate them? If always the same, just for that reason I wouldn't like it activated at all. I almost always drive my paddle vehicles in manual mode, so that'd be my preferred method of circumventing AFM. But don't like the unnecessary complication of having that crap on my car, but guess you have to look at it as it saved us some moolah in possible gas guzzler fees.
Drifting
Joined: Sep 2020
Posts: 1,461
Likes: 1,200
From: DFW
That is true, and that brings me to my question: Are you always stressing the same 4 cylinders more than the idle 4? Or the ECU is smart enough to vary which cylinders are powering the vehicle, to rotate them? If always the same, just for that reason I wouldn't like it activated at all. I almost always drive my paddle vehicles in manual mode, so that'd be my preferred method of circumventing AFM. But don't like the unnecessary complication of having that crap on my car, but guess you have to look at it as it saved us some moolah in possible gas guzzler fees.
Race Director
Joined: Aug 2016
Posts: 12,812
Likes: 10,229
From: Garden Valley CA
You don't appear to get the picture of what is happing! The folks pushing zero CO2 emissions are NOT going to Rich, Corvette, Ferrari etc owner's just pay money to pollute the earth with CO2. The 2012 EPA plan to have Corvettes require ~39 mpg by 2025 was a Prohibitive Fine of the manufacture if the EPA set goals by car family was not met! (That plan was stopped with a Pen BUT the new Pen reinstated one with 10% lower requirement in 2026 BUT no details. That will be announced January 2025! NOPE can't just pay money and destroy the world!