maxp

I know this has probably been asked before but numerous searches have not produced anything: can the NPP exhaust on the C7 be opened/closed like on the C6 with a M2W switch? (On my previous C6's I would have the exhaust open about 90% of the time). I have checked the C7 operational and infotainment manuals but don't see anything about exhaust control.
Thanks for any feedback.

Boiler_81

The best thread on the C7 NPP exhaust system. The information is factual and up to date. https://www.corvetteforum.com/forums...ck-result.html

Rooster OG

There's no need for a mild to wild switch. Sound management is handled by the selector switch, so going from tour to sport or track will change the exhaust sound. You can also set it up to operate independent of the drive mode if you want to run in say track sound all the time.

Kevin Schneider

How do you set the exhaust to be open all the time on a C7 Z06?

Foosh

It's in the settings menu on the center screen. The choices are "mode dependent," which means open in Sport or Track, or "off" which means always open.

Boiler_81

In order to meet Federal Drive by noise standards, the valves close even in track mode. The only way to keep them open is to pull the fuse or wire in one of the solutions outlined in the thread previously referenced.

I pulled the fuse and just leave it open at all times. If I were going on a long drive and want to tone it down, I would pop the fuse back in and control the exhaust from the cabin.

I recommend you start with just using the control in the car. Some people don't notice the valves closing for the Federal test parameters. If you hear the "hitch" and it bothers you, do the fuse pull or wire in one of the solutions.

Foosh

I know I've read they close "sometimes," but I sure don't notice it in street driving. Thus, I've seen no need to pull the fuse. My setting selection is always "off" which means almost always open. :-)

Boiler_81

Like I said, some people notice it others don't. It may be a difference in driving style, hearing or something else. I certainly noticed it and it bugged me. Therefore I pulled the fuse.

From the previously linked thread:

"UPDATE 9/30/2015: I had the opportunity (surreal quite frankly) to meet Tadge and Harlan at a private event today. I spoke privately with the two of them for about 10 minutes, and one of my questions was the NPP programming. Tadge's comment was something like "If we didn't do it that way, we wouldn't be legal". Meaning that even in Track mode, the valves need to close for the dB requirements in the FMVSS pass-by noise regulations.

meyerweb (in post #252 in this thread) figured all this out a while back and is 100% correct that the NPP programming is architected around the FMVSS pass-by noise regulations.

https://www.corvetteforum.com/forums/...post1589760867"

UsernameProtected

I'm just a control freak, so I wired the relay in so I can control it wirelessly with the Homelink visor. Love it this way.

Foosh

I don't think it's my driving style that causes me not to notice it. I do spend a lot of time in the upper rev ranges, but our streets are so rough I'm often in Tour mode w/MSRC on the street w/ the valves open. My best 50-mile fuel economy average is 20.1 mpg. On our smoother roads, I do use Sport as well.

I suppose I should pull the fuse to see it there's a difference, but have always been plenty happy w/ the engine music.

Dif

that thread explains EVERYTHING

maxp

Thanks, this is exactly the information I was looking for.

joemosfet

DashControl unit plugs into ODB2 port, allows you to show any pids on the dash, set up shift alarms, etc, and gives the ability to override the NPP functionality for true always-open or always-closed functionality by using the mirror selector switch. (L = always open, R = always closed, Middle = let the car decide.)

Boiler_81

I would be interested in what you find. There have been several threads on NPP. In them there are people who are adamant they can't hear a difference and then there are those who like me who can clearly hear the "hitch".

long_tall_texan

Great thread. Thanks for all the info. I have a non-electronics related NPP question. Has anyone dissected a C7 NPP muffler? Wondering what the inlet and outlet diameters are. Also wondering if the "open" side is a perforated tube like most C6 NPP or if it is a solid tube like C6 ZR1 and 12-13 NPP.

I'm curious, because I've been considering a C6 ZR1 exhaust swap on my 2007 Z06. But I ran across a smoking deal on C7 Z06 mufflers. I don't think I'd have much trouble manually wiring an open/close M2W type switch to actuate the butterfly valve on the C7 mufflers. Just curious if anyone has tried that yet.

and yes, i did search, but found nothing... If I missed it, please direct me. TIA for any insights.