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The valves do close in a range of RPMs (I don't remember the range of RPMs but I believe it is high teens to mid 2000; someone else will probably chime in on that with the exact numbers). The reason that the valves close in that range is to meet federal noise guidelines.
There have been a number of posts about NPP in Track Setting and IF they are closed.
I have my NPP set at always Track. But this is an easy test to show why I think they open at 1700 rpm. With my M7 in 4th direct drive at ~1200 rpm I floor it. When it reaches ~1700 rpm there is a step chage in sound to very loud.
Believe they close so there is no drone at highway speeds. FWIW
There have been a number of posts about NPP in Track Setting and IF they are closed.
I have my NPP set at always Track. But this is an easy test to show why I think they open at 1700 rpm. With my M7 in 4th direct drive at ~1200 rpm I floor it. When it reaches ~1700 rpm there is a step chage in sound to very loud.
Believe they close so there is no drone at highway speeds. FWIW
This is true unless one pulls the fuse. I have the mild to wild switch and when I close the valves on the highway it makes a big difference.
Outside of parts removal/replacement, in your touch panel, go into settings (gears) and you will find subsections in there for driving mode and engine sound management. Switch it to track, it will keep the baffles open most of the time allowing you to rev the engine to get that sound you are looking for.
Question to all, I have seen in the forum where individuals have had complaints with a "smell" after installing headers. Can someone please explain what they are referring to/cause and what the alternatives are to avoid the "smell" that's being reported?
You could always bang a nail into the muffler and remove the nail leaving a nice hole
You know, reading this I was thinking of a similar solution. Just poke a hole in the underside of each of the mufflers with a screw driver. If it gets too loud .... just slap a piece of duct tape over the hole.
You know, reading this I was thinking of a similar solution. Just poke a hole in the underside of each of the mufflers with a screw driver. If it gets too loud .... just slap a piece of duct tape over the hole.
I installed a Borla X pipe removed the secondary CATs.
made a difference but wasn't happy still.
So I found a post on muffler mod.
I did it and LOVE the sound not over the top in my book.
Cut the muffler open and blocked off the pipe inside.
NO MORE MUFFLER.
Modified the muffler actuators , you don't want them closed or the exhaust will back up into the engine.
The Borla X-pipe was the cheapest and easiest route to cure the soft exhaust. It opens up nicely, but does not drone or become obnoxious. Still have ARH catted headers for the C7, but waiting on a C7 Z to put them on. The car will really scream with that combo together.
10-18-2018, 10:05 AM
