Ihave a question about the exhaust on my 2016 M7 with npp. I always run in sport or track mode with flaps open. It seemed too quiet. The inner 2 pipes don't run any exhaust through them. 900 miles and there's never been any exhaust run through them. The outside pipes get hot and dirty but the 2 inside pipes are clean and cold. I always thought the inners always ran exhaust and the outside pipes only ran when in a certain mode.What am I missing here? Thanks.

 

Inside two pipes are for exhaust after it goes thru the mufflers. If you are always running in sport or track mode, you basically bi-passing the mufflers and running straight pipes, which are the two outside pipes. Exhaust will take path of least resistance, and that is thru the outside pipes when they are in the open position.

 

Thanks I had corsa extremes on c6 and loved the sound. this car is way quieter.

 

You can pull fuse 42 and completely disable the NPP at lower speeds and that will help 'a little'. I'm going to just end up getting an aftermarket axle back to help out with the sound. It just isn't loud enough for me either!

 

you can also set them to be open all the time also & never have to touch it again with out pulling the fuse.

 

Actually...no you can't. They will still close at certain rpm/throttle/speed combinations to pass fed.gov sound protocols

 

jknox is right. Without pulling the fuse, they will never be open 100% of the time. More like 95%.

 

This is true. I pulled the fuse, and mine is now definitely louder- especially at lower RPMs.
Worth trying since it's a free mod.

 

they open at 1700 rpm. Then they stay open.

 

Get Corsa Extremes...Problem solved!

 

I put on the Corsa X-Pipe and the Corsa Xtreme axle-back with four 4.5" black chrome tips.

It does delete the NPP functionality, but I'm old school and want V8 sound at all times from an American V8. I also didn't like the stainless steel outer exhaust tips requiring constant cleaning, plus the black chrome matches my vehicle murdered out look.

The four outlets distribute the exhaust equally at all times.

It is only a weekend fun car, and I never cold start it before later in the morning on weekends. It is ferocious loud upon cold start, then settles into a solid, deep V8 rumble at idle.

It actually now sounds like an early C3 big block Vette with side pipes.

Some say a Corsa exhaust sounds like an "exotic", but i don't hear it. I only hear deep V8 sounds. If you put any amount of pressure on the gas peddle, it sounds incredibly good, and people on a street are going to look to see what is being driven. I didn't do it for this reason, I'm just letting you know the exhaust sound is much louder at all RPMs, and constant. It's nothing like the stock exhaust. Anything over 3500rpm is going to be heard for a long distance. If you are over 5000rpm, you're going to scare people and traffic around you.

 

Here's what you can do:

1) change the Sound Management setting to Track mode.

2) pull fuse 42 to force it to be in Track mode at all times; even in lower RPM but, lose the ability to change it on the fly.

3) Install an off road x-pipe from Borla or Corsa to liven it up a little bit more.

4) Take the bigger leap - install a set of headers or an axle back muffler system.... or both!

5) do the muffler delete custom option.


I did my mods in stages because I wanted it louder but, also wanted to keep the NPP (driving from Nashville to Detroit it's nice to make the sound go away sometimes - like when you are on the phone). Corsa offroad x-pipe first - made the stock system sound a little more snappier. Then Borla Atak dual mode mufflers - made a bigger difference for sure and kept NPP but, not enough. ARH mid-length headers - that's when it came together for me.

 

Good thread, just what ive been looking for, so im just about to get my 500m service and then start mods.

I think the exhaust is probably the first thing. I have a question to those who have already done this.

I have a Boss mustang with side as well as rear pipes, i have electronic valves that can send the exhaust just to the rears or open all four, im guessing this is similar to the Vette right having read the notes above.

I do like the fact the vette can run stealth on highway driving but want to make it sound better for sport driving, which axle backs are best for that?

ian

 

I'm running sport about 60% of the time, track on occasion and tour the rest of the time. When I pull the roof panel I am in sport all the time. Love the sound.

 

So, on the Boss did you remove the restrictor plates that go to the side exits yet??

Corvette has AFM and on the right model NPP.

Stock x-pipe:


Corsa double helix off road pipe:



View of axle area while changing out mufflers. You can see location of AFM valves in this photo by the axles:


Borla Atak dual mode mufflers - shows AFM valve location and NPP value location (at back of mufflers):


Stock headers:


ARH mid-length headers:

 

Both our Street (#19172) and Competition (#19173) exhaust systems will maintain the use of all 4 valves, so you don't have to make any compromises!

 

Your exhaust system looks great! Do you have any decibel data on the street versus competition versions? Or how they both compare to the factory NPP system? I have the NPP but it is a little lacking for me so the option of a more aggressive sound with the control of the various sound management modes is very attractive to me...

 

I was really looking forward to listening to the video clip on the magnaflow tv section on youtube.

I had Magnaflows on my 2014 gt mustang that i sold to help fund the C7 and the sound those pipes made on the Mustang were the best i ever had.

However, having listened to the youtube video i wasnt as impressed as the corsa's

 

The Competition system sounds like it would work best for you. We dont have exact decibel numbers at this time, but the street should be ~87db and the competition ~94 at WOT. Compared the the NPP, the street exhaust would be about the same volume, with an overall improvement in tone, and the Competition would be slightly more aggressive.

Everyone will have different preferences when it comes to exhaust, which is completely ok, but we do suggest basing your opinion off of the way the system sounds in person. Unfortunately videos never fully capture the true sound of any exhaust.

 

How can I tell if I have NPP exhaust?