CourtneyJudd

I need some light on this subject! I have 2014 Z51 7 speed with the NPP option. In the setting display there are two options: automatic and OFF. I have selected both but can't tell any difference in exhaust sound in either setting. I also bought mild to wild and installed it and tried it with both settings but not much difference. The manual is not much help here so i would like someone to explain what really goes on here with the NPP. Thinking about going with an aftermarket system but I really want to understand exactly how this all sorts out before I drop a lot of bucks! Thanks for any help! Courtney

NSC5

The auto selection changes the exhaust sound based upon driver mode selection ranging from quiet in tour mode to loudest in track mode by keeping the NPP control valves open under more conditions (the valve either allows or prevents exhaust through the outer pipes which are the less baffled path). The off setting is equivalent to the track setting all of the time and leaves the NPP valves open MOST of the time regardless of driver mode setting. The valves are not always open because the stock system still has to meet federal noise requirements.

I have a 2016 Z06 and the different NPP modes are very noticeable.

I am not sure how the mild to wild setup works with the C7; I presume it directly controls the NPP valves leaving them either open or shut depending upon the mild or wild setting. Any chance the mild to wild was installed improperly resulting in the NPP system not working?

eboggs_jkvl

My M2W keeps the NPP open at all times or "Normal" Normal and when it shifts to 4th (A6), the NPP will close. If I operate the M2W, then the NPP valves open even in 4th or higher.

I believe you want "Automatic" as your option. The NPP is open in 1st - 3rd. 4th is where it makes a difference for open valves or closed.

Elmer

CourtneyJudd

thanks for the info, m2w simple install, fuse tap and remote fob on or off. Just takes the place of the fuse controlling the NPP. I just don't see much difference in any way I set it. I have the Corsa Pace Car on my 2004 and thinking about doing that with this 2014... maybe that will improve the sound. I did email the folks at M2W and they said the 2014 computer was very limited for control of the exhaust.... who knows! lol, but thanks, I do appreciate the response! Courtney

lakemg

I suspect that if your drive mode is set to sport or track and you set the NPP to off, you wouldn't hear a difference. If you put your drive mode in ECO or Tour and then switched between auto and off on the NPP, you might hear a difference.

DAFFYDRUNK

Possible the OP's car doesn't actually have npp? On my 15 it's obvious when open. There's probably some way to tweak it, but it's fully open when started cold, and closes after several seconds. It's almost obnoxious starting the thing except it sounds so cool.