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As I understand the valves are NO, normally open, and why it is loud at the first second of start up (they need a second to close the valves if you are not requesting them to be open via the console setting), therefore pulling the fuse disables them from ever closing. Just go into the settings and select quiet mode or loud mode and don't bother with pulling the fuse. That's the whole point of having the NPP, user selectable from the drivers seat.
As I understand the valves are NO, normally open, and why it is loud at the first second of start up (they need a second to close the valves if you are not requesting them to be open via the console setting), therefore pulling the fuse disables them from ever closing. Just go into the settings and select quiet mode or loud mode and don't bother with pulling the fuse. That's the whole point of having the NPP, user selectable from the drivers seat.
There are a second set of valves the AFM controls from what I have read.
There are a second set of valves the AFM controls from what I have read.
Yeah 2 pre muffler above the rear axles and 2 at the muffler. You can control the two at the muffler as I understand it, while the other two are tied into the tune for the AFM and you can't control them without getting into the cars brains if you will. I always hear a thud when mine close above the axles. I would like a way to control them but without a tune I know no way to do that. Good luck and have fun with your car!
Last edited by Yourconfused; Apr 5, 2019 at 12:19 AM.
With the NPP fuse pulled and the range device installed all 4 valves are open and sound AWESOME when going through gears ( I also have a Borla X pipe installed)
Follow up....I have a manual. As far as I know, the AFM is only enabled on eco mode. So if I am in sport then both sets (all 4) should be open right? Sport has them open and AFM is not enabled.
Follow up....I have a manual. As far as I know, the AFM is only enabled on eco mode. So if I am in sport then both sets (all 4) should be open right? Sport has them open and AFM is not enabled.
Yes I do believe AFM even closes valves in sport at certain RPM"s.
When gear shifter in M, AFM will never close valves from what I read.
I have A6, so not certain, but yes in eco AFM closes valves on M7 from what I have also read.
I ordered the Range AFM Disabler last night. Today I drove to work with NPP fuse pulled, and drove in manual mode so exhaust sounded correct and open the whole time.
Yes I do believe AFM even closes valves in sport at certain RPM"s. When gear shifter in M, AFM will never close valves from what I read.
I have A6, so not certain, but yes in eco AFM closes valves on M7 from what I have also read.
Follow up....I have a manual. As far as I know, the AFM is only enabled on eco mode. So if I am in sport then both sets (all 4) should be open right? Sport has them open and AFM is not enabled.
The Sport Setting opens the muffler valves more than Tour but there are certain operating characteristics where the valves will close. Track is the only setting where the muffler valves are open all of the time (except during V4 operation). I have a 2015 Z06 M7 which doesn't have any valves ahead of the mufflers so don't have to worry about those. I use Engine Sound Management to set my exhaust in Track Mode and it is open all of the time except if I select Eco Mode. When in Eco Mode I can clearly hear the muffler valves close and open as the engine switches from V8 to V4 and back to V8 mode. There is a very definite change in sound level even when running in 6th gear at 1200 rpm with cruise control set. Around town I don't rip through the gears but when on track the loud pedal is mostly on the floor. When it comes to cleaning my tailpipe extensions I usually only have to clean the outer pipes as the inner pipes rarely get dirty.
You are kind of confused. AFM Active Fuel Management (also known as DOD Displacement on Demand) is the engine going into 4 cylinder mode. The AFM valves are ahead of the mufflers. The AFM valves close when in 4 cyl mode to partially restrict the exhaust. M7 can only go into 4 cyl mode when drive mode is set to ECO. A6 / A8 can go into 4 cyl mode in any drive mode. The Range module disables AFM mode for A6/A8.
Sound management for cars with Performance Exhaust (code NPP) have valves on the outer exhaust pipes. These pipes partially bypass the muffler. With the fuse installed these valves will close off at low RPMs in all drive modes (except maybe track?). You can hear a change in exhaust sound around 1600 - 1800 rpm.
Pulling the appropriate fuse labelled Exhaust 2 will leave the NPP valves open all the time. Fuse # 41 (2014), #42 (2015 - 2018), #87 for 2019.
There are dozens of threads on this going back to 2013.
Hope this helps.
Ron
Last edited by RonC7; Apr 5, 2019 at 04:32 PM.
Reason: .
If exhaust valve is the only concern, wouldn't the engine sound management setting of track or sport keep all 4 open all the time and eliminate the need to pull the fuse?
Way back in the earlier threads it was noted that NPP valves need to be closed at times to meet noise regulations. I don't recall the reasoning for the AFM valves - increased back pressure when in 4 cyl mode may be needed for most efficient exhaust function and does change exhaust tone. I do know that 4 cyl mode + NPP valves open when driving around town does not sound anything like a Corvette to me - so I rarely use ECO mode even on the interstate.
If exhaust valve is the only concern, wouldn't the engine sound management setting of track or sport keep all 4 open all the time and eliminate the need to pull the fuse?
From previous threads on this, the answer is no. There are times where they will still close or partially close. The only way to keep them truly open all the time is to pull the fuse or use M2W.
That said, it is a negligible difference....most people would probably not notice the time when they move if you have them set to be open from the sound management setting.
Pulling the fuse does no harm. To me it comes down to this......
If you're one that constantly switches the setting back and forth (open/close) M2W is a good option for you. It's much faster than trying to go through the screens.
If you don't switch back and forth and just want them "open" try pulling the fuse and the sound management setting. See if you notice any difference at all. If you don't think you notice a difference, leave your fuse in place and use the sound management setting.
Got the range AFM disabler in today drove the car home with it and worked exactly how I expected it to. Exhaust sounds perfect and consistent with NPP fuse pulled.
( I also have a Borla X pipe installed)
