AFM operation question
Thread Starter
Instructor
Joined: Apr 2021
Posts: 143
Likes: 63
From: Orlando, FL
AFM operation question
My Stingray originally had the non-NPP exhaust. (AFM’s but no NPP’s) I bought a used stock Z06 exhaust and had it installed. (NPP’s but no AFM’s) The NPP valves are open all the time so, basically, straight pipes.
I left the AFM actuators plugged in and tie wrapped to the frame to fool the ECM. I also have a Range AFM disabler plugged in the OBD so it never goes into the 4-cylinder mode.
Here’s my question: I’m planning a 400 mile trip and want to unplug the Range so the AFM system operates as designed to increase the fuel economy. Will it damage the engine to have it go into 4-cylinder mode but not have the extra back pressure in the exhaust?
Thanks
Ron
I left the AFM actuators plugged in and tie wrapped to the frame to fool the ECM. I also have a Range AFM disabler plugged in the OBD so it never goes into the 4-cylinder mode.
Here’s my question: I’m planning a 400 mile trip and want to unplug the Range so the AFM system operates as designed to increase the fuel economy. Will it damage the engine to have it go into 4-cylinder mode but not have the extra back pressure in the exhaust?
Thanks
Ron
Pro
Joined: May 2022
Posts: 566
Likes: 242
From: Peoria, Arizona
If v4 mode causes unwanted vibrations in the drivetrain, I would not want to subject it to prolonged exposer from a long road trip. Even if it saved me a little gas. That's your call, but once damage is done, you can't reverse it.
Racer
Joined: Sep 2021
Posts: 321
Likes: 119
From: Illinois
I think you can hurt the motor just by using the AFM system as designed because of the flawed design of the DOD lifters that many have had problems. Although using the system one time to go into V4 mode shouldn't hurt anything, why risk it for that extra couple mpg? I wouldn't ever let the system activate and I actually deleted it with a cam swap the first chance I got. I think that system creates a lot of problems and using it for prolonged periods and frequently, can really damage something as the system is not very good imo. I would keep that range device plugged in, but that's just me. I personally don't like the thought of using the system at all, but totally up to you. Hope everything works out whatever you decide to do.
Tech Contributor
Joined: Oct 1999
Posts: 41,037
Likes: 9,801
From: Charlotte, NC (formerly Endicott, NY)
My Stingray originally had the non-NPP exhaust. (AFM’s but no NPP’s) I bought a used stock Z06 exhaust and had it installed. (NPP’s but no AFM’s) The NPP valves are open all the time so, basically, straight pipes.
I left the AFM actuators plugged in and tie wrapped to the frame to fool the ECM. I also have a Range AFM disabler plugged in the OBD so it never goes into the 4-cylinder mode.
Here’s my question: I’m planning a 400 mile trip and want to unplug the Range so the AFM system operates as designed to increase the fuel economy. Will it damage the engine to have it go into 4-cylinder mode but not have the extra back pressure in the exhaust?
Thanks
Ron
I left the AFM actuators plugged in and tie wrapped to the frame to fool the ECM. I also have a Range AFM disabler plugged in the OBD so it never goes into the 4-cylinder mode.
Here’s my question: I’m planning a 400 mile trip and want to unplug the Range so the AFM system operates as designed to increase the fuel economy. Will it damage the engine to have it go into 4-cylinder mode but not have the extra back pressure in the exhaust?
Thanks
Ron
AFM doesn't really get you much better fuel mileage. On my Z06 I might be able to get 1 mpg on the highway if I pay attention to what I am doing and choose the correct gear to run in for the speed I am running at. For instance, with my M7 I get better mpg at 70 mph if I run in 6th gear rather than 7th gear when in ECO drive mode. At 70 in 7th gear, the engine runs mostly in V8 mode whereas in 6th gear it runs mostly in V4 mode.
Bill
