V8 drops to the v4
Thread Starter
2nd Gear
Joined: Mar 2024
Posts: 2
Likes: 0
From: Carml NY
V8 drops to the v4
I posted this a few days ago, and saw a thread of about 51 responses, owners all having the same issues, but no solution other than turning the radio up!
Does anyone know of a real solution?
posting
" have 2024 HTC and hear the same noise when V8 drops to the v4, Is there a solution to get rid of this? I hate to bring it in for them to tell me they see nothing.
Does anyone know of a real solution?
posting
" have 2024 HTC and hear the same noise when V8 drops to the v4, Is there a solution to get rid of this? I hate to bring it in for them to tell me they see nothing.
Popular Reply
Apr 24, 2024, 10:46 AM
Pro
Joined: Jul 2023
Posts: 535
Likes: 516
The only way I know it goes from V8 to V4 is by the light on the dash. I never feel it or hear it. Mine must be one of the few that GM actually built right. I never hear injectors ticking either. Both issues would bother me to the point of selling the car.
Instructor
Joined: Mar 2022
Posts: 213
Likes: 149
From: Westminster, CA
i hear the same click noise when the AFM valves and lifters engage. there is nothing that can be done about the noise. just like the ticking noise of the injectors, all you can do is mask the sound by turning up the radio.
As mentioned above, if you drive in manual mode or have the engine settings to track mode, it disables AFM so you will be in V8 mode the whole time
As mentioned above, if you drive in manual mode or have the engine settings to track mode, it disables AFM so you will be in V8 mode the whole time
Melting Slicks
Joined: Aug 2000
Posts: 2,425
Likes: 1,198
From: Early 2020 Z51 Coupe, Original Owner, Ahwatukee Foothills, AZ
One Real Way to pernamently disable the C8 AFM/V4 is the HPT unlock and tune.
My C8 is Flex Fuel tuned. Dynojet's at 484 rhp / 466 rtq with No AFM/V4. Where I live Premium 91 is $1.50 a gallon more expensive.
https://www.corvetteforum.com/forums...o-vs-a-c8-z.ht
My C8 is Flex Fuel tuned. Dynojet's at 484 rhp / 466 rtq with No AFM/V4. Where I live Premium 91 is $1.50 a gallon more expensive.
https://www.corvetteforum.com/forums...o-vs-a-c8-z.ht
Drifting
Joined: Sep 2020
Posts: 1,453
Likes: 1,194
From: DFW
One Real Way to pernamently disable the C8 AFM/V4 is the HPT unlock and tune.
My C8 is Flex Fuel tuned. Dynojet's at 484 rhp / 466 rtq with No AFM/V4. Where I live Premium 91 is $1.50 a gallon more expensive.
https://www.corvetteforum.com/forums...o-vs-a-c8-z.ht
My C8 is Flex Fuel tuned. Dynojet's at 484 rhp / 466 rtq with No AFM/V4. Where I live Premium 91 is $1.50 a gallon more expensive.
https://www.corvetteforum.com/forums...o-vs-a-c8-z.ht
Advanced
Joined: Mar 2024
Posts: 60
Likes: 14
If you're dealing with noise and vibration because of the cylinder deactivation feature, there's a gadget called an AFM disabler that can help. It plugs into the OBD-II port and turns off the feature, keeping your engine running on all eight cylinders all the time. This should stop the noise and vibration when the engine switches to V4 mode, but keep in mind, you'll probably see worse fuel efficiency. Plus, it could void your warranty or cause problems with emissions, depending on where you live.
Another option is custom engine tuning. Some shops can tweak the engine's settings to turn off the AFM system and fine-tune other performance aspects. This can be a more seamless solution, but it comes with similar risks to the warranty and emissions. It's definitely worth considering if you want a smoother engine, but make sure you're aware of the possible downsides.
Another option is custom engine tuning. Some shops can tweak the engine's settings to turn off the AFM system and fine-tune other performance aspects. This can be a more seamless solution, but it comes with similar risks to the warranty and emissions. It's definitely worth considering if you want a smoother engine, but make sure you're aware of the possible downsides.
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Burning Brakes
Joined: Nov 2022
Posts: 1,059
Likes: 1,118
From: Western Mass
If you're dealing with noise and vibration because of the cylinder deactivation feature, there's a gadget called an AFM disabler that can help. It plugs into the OBD-II port and turns off the feature, keeping your engine running on all eight cylinders all the time. This should stop the noise and vibration when the engine switches to V4 mode, but keep in mind, you'll probably see worse fuel efficiency. Plus, it could void your warranty or cause problems with emissions, depending on where you live.
Another option is custom engine tuning. Some shops can tweak the engine's settings to turn off the AFM system and fine-tune other performance aspects. This can be a more seamless solution, but it comes with similar risks to the warranty and emissions. It's definitely worth considering if you want a smoother engine, but make sure you're aware of the possible downsides.
Another option is custom engine tuning. Some shops can tweak the engine's settings to turn off the AFM system and fine-tune other performance aspects. This can be a more seamless solution, but it comes with similar risks to the warranty and emissions. It's definitely worth considering if you want a smoother engine, but make sure you're aware of the possible downsides.
Pro
Joined: Jul 2023
Posts: 535
Likes: 516
The only way I know it goes from V8 to V4 is by the light on the dash. I never feel it or hear it. Mine must be one of the few that GM actually built right. I never hear injectors ticking either. Both issues would bother me to the point of selling the car.
Race Director
Joined: Mar 2007
Posts: 11,395
Likes: 8,559
1. I can hear it. I can feel it. It does not bother me generally, but in leisurely cruises on rural roads, it does enter and exit V4 mode frequently and then I find it annoying. So, I go to manual shift mode for that.
2. Ways to disable that come with the car - a) manual shift mode, in any Drive Mode. b) set engine/shift to Track in Z mode. c) use Track Driver Mode.
3. Disabling device - there is no device that can be plugged in to disable it. (unlike previous models).
2. Ways to disable that come with the car - a) manual shift mode, in any Drive Mode. b) set engine/shift to Track in Z mode. c) use Track Driver Mode.
3. Disabling device - there is no device that can be plugged in to disable it. (unlike previous models).
Race Director
Joined: Mar 2007
Posts: 11,395
Likes: 8,559
I can detect the V4 mode, with the top up or down, but much more noticeable with the top down. I suspect its because, besides sound of the actuators or the subtle change in feeling, there is change in the exhaust note - because all the muffler valves close in V4 mode.
Burning Brakes
Joined: May 2014
Posts: 1,035
Likes: 580
From: Cape Coral, FL
Melting Slicks
Joined: Aug 2000
Posts: 2,425
Likes: 1,198
From: Early 2020 Z51 Coupe, Original Owner, Ahwatukee Foothills, AZ
6th Gear
Joined: Apr 2024
Posts: 6
Likes: 0
From: Boise, ID
better oil change needed?
I posted this a few days ago, and saw a thread of about 51 responses, owners all having the same issues, but no solution other than turning the radio up!
Does anyone know of a real solution?
posting
" have 2024 HTC and hear the same noise when V8 drops to the v4, Is there a solution to get rid of this? I hate to bring it in for them to tell me they see nothing.
Does anyone know of a real solution?
posting
" have 2024 HTC and hear the same noise when V8 drops to the v4, Is there a solution to get rid of this? I hate to bring it in for them to tell me they see nothing.
Advanced
Joined: Jun 2019
Posts: 72
Likes: 32
From: Central Kentucky
After driving my 2022 HTC Z51 for 3000 miles, I started hearing a loud ‘clunk’ when the C8 switched to V4 mode (the AFM valves). I thought about taking it into Chevy under warranty, but I was looking at aftermarket exhausts anyways. Driving with the top down was obviously louder. I was frustrated, so I installed an aftermarket Lemans Edition track exhaust with no AFM or exhaust valves. No more ‘clunk’ sound over to V4, but I don’t like the deeper V4 tone when it switches. Drive in manual except when on the interstate to save gas. Made the car 2x as fun to drive and no more ‘clunk’!