snaponjackson

I am stumped. I purchased a Diablo Intune because I want the AFM
turned off. According to the Intune the AFM is off and this was verified
by Diablo Techs. I thought that turning off AFM would keep the exhaust
valves open (because the engine stays in V8 mode). But my valves still close when at cruise speed making my exhaust go silent. Any insight on this issue would be much appreciated. Chris

meyerweb

How do you have ESM set in the infotainment screen vehicle options, and what driving mode are you using with the console ****?

There are a ton of threads on this, but there are two sets of valves. The AFM valves are located upstream of the mufflers, and close partially when the engine is in V4 mode. The NPP valves are behind the mufflers, and are controlled by the ESM setting and/or the driving mode. Tuning out the AFM has no effect on the NPP valves.

Also, even if the NPP valves are open, the car still gets pretty quiet at cruise, simply because at the low RPMs the car cruises at there's not very much exhaust flow to make noise.

tblu92

You have to realize there are 2 sets of butterflies in your exhaust
The most forward ones close when the AFM is engaged
The most rearward ones are used by the NPP exhaust system---
If you deleted your AFM the front ones will be open all the time
however the rear ones will only open if you switch them to open OR
if in your dash settings you set them to open all the time permanently via the sound management settings

xp800

Both meyerweb and tblu covered the valve and Engine Sound Management parts. BUT, even with the ESM set to Track (or Off if 2014), the NPP valves will STILL CLOSE at times. This is what you're hearing. The ONLY way to keep the NPP valves open ALL the time is to pull the fuse. If this is what you want, then pull fuse 41 (for a 2014) or fuse 42 (2015+) in the engine bay fuse box. This overrides the ESM settings permanently (they no longer have an effect) until the fuse is put back.

There are literally dozens and dozens of threads on this if you search.

bob guzzy

If its a 2015 pull fuse 42(under the hood) its just like disconnecting the vac hose on the c6 NPP the rear valves stay open at all times.

I hated when the valves would close just when I wanted the sound of the exhaust it would go quiet.