NPP necessary?
Melting Slicks
Joined: Aug 2014
Posts: 2,746
Likes: 916
This is not my video, but here's one that I found on the web that shows that even with long tube headers and high flow cats, you can go from mild to wild with the stock NPP mufflers. This is the exhaust sound that I'm aiming for...
Enjoy...
Enjoy...
Last edited by lakemg; Aug 7, 2016 at 07:51 PM.
Team Owner
Joined: Jul 2006
Posts: 97,155
Likes: 1,471
From: Calgary, AB. There's a reason why white was the only color offered on every year Corvette. Proud Canadian German Jamaican!
St. Jude Donor '09, '12-'13-'14-'15-'16-'17
Depends if you want to change your exhaust for an aftermarket one later, no need to waste your dough if you're just going to replace it. You can get a much louder exhaust aftermarket and probably free up more bhp if you go that route.
Thread Starter
Advanced
Joined: Jun 2016
Posts: 50
Likes: 2
From: Washington DC
As you can see, NPP is very popular. I will, however, give you a different take.
First, NPP pluses: Great looks and greatly improved sound.
Now the minuses: Improved sound compared to what? Compared to stock, of course. But the stock sound is so pathetic, anything sounds good by comparison.
Your salesman will tell you that, as an added benefit, NPP allows you to control the sound: loud when you want it, soft when you don't. But that's not entirely true. NPP sounds great initially, but then goes soft on its own, even when you have it set to stay loud all the time. In fact, the computer, not you, decides when it wants to be loud or soft. Major design flaw, IMO.
As a couple posters in this thread have advised you, the workaround is to pull a fuse. If you don't mind doing that, you're good.
Others have reported (not recently) that pulling a fuse will throw a code. Still others (more recently) have said that pulling the fuse will not throw a code. Finally, some have complained that NPP, while far better than stock, is still too quiet.
I'll add another NPP benefit: It comes from the factory. You're done.
The alternative, what I did, is to order the stock exhaust, then immediately have my Chevy dealer swap it for an aftermarket exhaust. Result: Great sound, great looks, and, important to me, no need to pull a fuse and no computer involvement with my exhaust sound.
Many choices. Good luck with whatever you choose.
First, NPP pluses: Great looks and greatly improved sound.
Now the minuses: Improved sound compared to what? Compared to stock, of course. But the stock sound is so pathetic, anything sounds good by comparison.
Your salesman will tell you that, as an added benefit, NPP allows you to control the sound: loud when you want it, soft when you don't. But that's not entirely true. NPP sounds great initially, but then goes soft on its own, even when you have it set to stay loud all the time. In fact, the computer, not you, decides when it wants to be loud or soft. Major design flaw, IMO.
As a couple posters in this thread have advised you, the workaround is to pull a fuse. If you don't mind doing that, you're good.
Others have reported (not recently) that pulling a fuse will throw a code. Still others (more recently) have said that pulling the fuse will not throw a code. Finally, some have complained that NPP, while far better than stock, is still too quiet.
I'll add another NPP benefit: It comes from the factory. You're done.
The alternative, what I did, is to order the stock exhaust, then immediately have my Chevy dealer swap it for an aftermarket exhaust. Result: Great sound, great looks, and, important to me, no need to pull a fuse and no computer involvement with my exhaust sound.
Many choices. Good luck with whatever you choose.
Racer
Joined: Jun 2001
Posts: 419
Likes: 72
From: Belvidere IL
No brainer to me....
My thoughts...had a C5 and used an after market exhaust. Great growl/howl but it was present at all speeds, i.e., the drown (sp?) while cruising was way too loud and annoying. C6 worked great with the "mild to wild" unit with my NPP. Nice to just push a button for some bad *** sound but also nice to push that button to get the quiet mode for interstate cruising.
C7 works great as you can adjust the mode you want. It's on the "sound management" screen.
Mine seems to work on baffles being open in the V8 mode but goes to closed when it operates in the V4 mode.
Keep in mind here that the car only goes to the V4 mode when "loafing" down the road.
Perfect as to my driving habits.
C7 works great as you can adjust the mode you want. It's on the "sound management" screen.
Mine seems to work on baffles being open in the V8 mode but goes to closed when it operates in the V4 mode.
Keep in mind here that the car only goes to the V4 mode when "loafing" down the road.
Perfect as to my driving habits.
Thread Starter
Advanced
Joined: Jun 2016
Posts: 50
Likes: 2
From: Washington DC
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Burning Brakes
Joined: May 2015
Posts: 891
Likes: 418
I bought a non npp vette and i was extreamly fustrated how quiet it sounds and for a while i been belly aching that i didnt have the npp. Last week i purchased the corsa extreme exhaust system and holy **** does it sound nice. I had it installed yesterday. After i installed it, i came to the conclusion that it was the righr move that i didnt get npp because it woulda been a waste of money if i didnt like it and replaced that. So the question is if you like the npp sound or do u see yourself wanting more? If you want more save ur money for a aftermarket exhaust system.
Burning Brakes
Joined: Apr 2014
Posts: 854
Likes: 302
The standard exhaust system is just too quiet. However, there will be times that you will appreciate the quiet - not disturbing the neighbors if you have to leave at O'dark 30 or perhaps some day you have the misfortune of living in a HOA. I chose not to pull the fuse and simply set the exhaust through the "Settings" control. As pointed out by others there will be times that the NPP still closes. I'm ok with that. I dislike the drone on the highway and with AFM engaged it gets worse. I was also sensitive to the warranty issues and decided I would not make any mechanical modifications for a few years. Bottom line: go with the NPP. You will not be disappointed.
Le Mans Master
Joined: Dec 2014
Posts: 6,140
Likes: 2,745
From: Northeast
I'd say that the NPP is a must have option. It's one of those features that if you decide you want it later it's nearly impossible to add it. That being said, I have the NPP but installed a Corsa exhaust system, which disables the feature.
Drifting
Joined: Jan 2006
Posts: 1,554
Likes: 158
We first have to define "necessary". I agree with others that the slight HP boost and look will make you an NPP fan. With NPP you can use the driving mode settings and/or the settings feature on the infotainment screen to make the Corvette almost sound softer like Grandpa's Buick or louder like a 30's street rod running straight pipes. Almost. I think NPP adds to the driving fun of the car. The system works great and is designed for the car. To me it was necessary because of how I enjoy driving the Corvette but to someone else maybe not so much. I also wanted larger tires and brakes of Z51 but the same question can be asked if Z51 is "necessary". To each his on. If you don't get NPP the Corvette will still start up and transport you where you want to go but to me Corvette has never been just about transportation.
Last edited by Nice Ride; Aug 7, 2016 at 11:29 PM.
Safety Car
Joined: Jun 2005
Posts: 4,905
Likes: 569
From: Bucks County PA
Pulling Fuse 41 or 42, depending on the year C7) will NOT throw a code. This keeps the exhaust loud except for 4 cylinder mode which in sport and track mode are very rare instances.
There is another Fuse (31 I believe) that allows it to stay loud in 4 cylinder mode, that will throw a code.
There is another Fuse (31 I believe) that allows it to stay loud in 4 cylinder mode, that will throw a code.
Last edited by yell03; Aug 8, 2016 at 08:05 AM.
Safety Car
Joined: Mar 2014
Posts: 4,482
Likes: 668
From: Kilmarnock Va
After hearing NPP on other C7's I decided to go aftermarket.NPP way to quiet for me.
I bought after market mufflers and now it's unbelievably loud.Plan on installing headers but
I'm hesitating because of the neighbors.
I bought after market mufflers and now it's unbelievably loud.Plan on installing headers but
I'm hesitating because of the neighbors.
Melting Slicks
Joined: Aug 2014
Posts: 2,746
Likes: 916
If you had the NPP you could still run quietly with headers by putting the NPP in stealth mode and then open it up when you get out of your neighborhood...check out the video I posted above
Drifting
Joined: Aug 2002
Posts: 1,519
Likes: 431
From: MI
In my opinion, this is the best thread on NPP functionality on the forum: https://www.corvetteforum.com/forums...ck-result.html
Pulling the fuse for the second set of valves does not and has never set a CEL. The fuse for the first set of valves will set a code. It is not necessary or desirable to pull that fuse.
The reason the computer takes over and overrides the setting is so the Corvette can pass the Federal Drive by noise standard. This is something the aftermarket does not have to do.
Pulling the fuse overrides this behaviour. This is what I have done and the sound is perfect for me. If I were to take a long Interstate trip, I would probably reinstal the fuse to regain cabin control over the sound.
There are solutions in the above thread for controlling the fuse from inside the cabin. Essentially they switch the fuse into and out of the the circuit remotely.
Pulling the fuse for the second set of valves does not and has never set a CEL. The fuse for the first set of valves will set a code. It is not necessary or desirable to pull that fuse.
The reason the computer takes over and overrides the setting is so the Corvette can pass the Federal Drive by noise standard. This is something the aftermarket does not have to do.
Pulling the fuse overrides this behaviour. This is what I have done and the sound is perfect for me. If I were to take a long Interstate trip, I would probably reinstal the fuse to regain cabin control over the sound.
There are solutions in the above thread for controlling the fuse from inside the cabin. Essentially they switch the fuse into and out of the the circuit remotely.
Burning Brakes
Joined: May 2014
Posts: 775
Likes: 372
From: Yukon Oklahoma
When I was in the process of buying my car off the showroom floor, they had to move another C7 without NPP to get mine out. I was standing behind both; so they started the non-NPP first and it was OK, but nothing spectacular. Then they came back and started mine, with NPP; a noticeable difference that even my wife noticed and commented on. A much better sound and not to the point where it was too loud; just right in my opinion. So, I would recommend.
