npp muffler question
Thread Starter
Instructor
Joined: Aug 2013
Posts: 104
Likes: 0
npp muffler question
Hi guys. I just ordered an npp exhaust system for my 2006 corvette and I was just wondering if I can manually keep the exhaust valve open for the npp. The thing is I don't have the money to wire a system to control it and would rather keep them open.any input with pictures and instructions if you can help will be much appreciated.
Burning Brakes
Joined: Mar 2012
Posts: 836
Likes: 43
From: Killeen Texas
Hi guys. I just ordered an npp exhaust system for my 2006 corvette and I was just wondering if I can manually keep the exhaust valve open for the npp. The thing is I don't have the money to wire a system to control it and would rather keep them open.any input with pictures and instructions if you can help will be much appreciated.
Last edited by dmoneychris; Mar 19, 2016 at 05:02 PM.
Tech Contributor
Joined: Jul 2002
Posts: 14,950
Likes: 264
From: St. Louis, MO
St. Jude Donor '08
I suspect, very strongly, you're not going to be happy with that system open all the time.. I've ridden in NPP cars when they are open, it's fun and sounds good cruising into a car show or at the drag strip.
But the constant drone at highway speeds is horrible. If you have headers, it's deafening as well.
But the constant drone at highway speeds is horrible. If you have headers, it's deafening as well.
Thread Starter
Instructor
Joined: Aug 2013
Posts: 104
Likes: 0
Well Joe g and d money thanks for the info. If it automatically goes to the open position then that would be awesome . I hope it does. And I'd about the drone I blast mt stereo anyway man. I hope they stay open
Tech Contributor
Joined: Jul 2002
Posts: 14,950
Likes: 264
From: St. Louis, MO
St. Jude Donor '08
I am pretty sure also that it defaults to open, that's why the cars "bark" when you first start them.
I'll just make one last warning comment... lol Guys my age (like David Freiberger editor of Hot Rod) who have this are cursing their decisions to not protect their ears as young bucks. I'm the guy folks make fun of with his fingers in his ears at the drag strip if I forget my ear plugs...lol
Even so it apparently hasn't helped, while I don't have ringing in my ears, my wife says I never hear what she's saying....
https://en.wikipedia.org/wiki/Tinnitus
I'll just make one last warning comment... lol Guys my age (like David Freiberger editor of Hot Rod) who have this are cursing their decisions to not protect their ears as young bucks. I'm the guy folks make fun of with his fingers in his ears at the drag strip if I forget my ear plugs...lol
Even so it apparently hasn't helped, while I don't have ringing in my ears, my wife says I never hear what she's saying....
https://en.wikipedia.org/wiki/Tinnitus
Thread Starter
Instructor
Joined: Aug 2013
Posts: 104
Likes: 0
Actually, I decided to do some investigative work of my own and from what I can't tell guys is the ones I ordered are in fact defaulted open. This I can tell by the position of the valve from a video I saw. When the valves are closed it's pressed closer against the valve, when the fuse is pulled for the npp they appear as the baffle is much more out ward. So, I think they are open and I hope they are when I get them
Thread Starter
Instructor
Joined: Aug 2013
Posts: 104
Likes: 0
I am pretty sure also that it defaults to open, that's why the cars "bark" when you first start them.
I'll just make one last warning comment... lol Guys my age (like David Freiberger editor of Hot Rod) who have this are cursing their decisions to not protect their ears as young bucks. I'm the guy folks make fun of with his fingers in his ears at the drag strip if I forget my ear plugs...lol
Even so it apparently hasn't helped, while I don't have ringing in my ears, my wife says I never hear what she's saying....
https://en.wikipedia.org/wiki/Tinnitus
I'll just make one last warning comment... lol Guys my age (like David Freiberger editor of Hot Rod) who have this are cursing their decisions to not protect their ears as young bucks. I'm the guy folks make fun of with his fingers in his ears at the drag strip if I forget my ear plugs...lol
Even so it apparently hasn't helped, while I don't have ringing in my ears, my wife says I never hear what she's saying....
https://en.wikipedia.org/wiki/Tinnitus
Burning Brakes
Joined: Mar 2012
Posts: 836
Likes: 43
From: Killeen Texas
I am pretty sure also that it defaults to open, that's why the cars "bark" when you first start them.
I'll just make one last warning comment... lol Guys my age (like David Freiberger editor of Hot Rod) who have this are cursing their decisions to not protect their ears as young bucks. I'm the guy folks make fun of with his fingers in his ears at the drag strip if I forget my ear plugs...lol
Even so it apparently hasn't helped, while I don't have ringing in my ears, my wife says I never hear what she's saying....
https://en.wikipedia.org/wiki/Tinnitus
I'll just make one last warning comment... lol Guys my age (like David Freiberger editor of Hot Rod) who have this are cursing their decisions to not protect their ears as young bucks. I'm the guy folks make fun of with his fingers in his ears at the drag strip if I forget my ear plugs...lol
Even so it apparently hasn't helped, while I don't have ringing in my ears, my wife says I never hear what she's saying....
https://en.wikipedia.org/wiki/Tinnitus
After a long tour in 'Trash-Can-Istan' & getting blown up inside of V-shape hull MRAP vehicles multiple times, I have a constant BEEEEEEEEE in my ears & there's no P on the end...I have a hard time hearing what my wife says also. She says; Something, Something, Something, You're always, Something, Something, You never, Something, Something, Something, Why don't you, Something, Something, Something...That's what I hear anyways...lol 
Last edited by dmoneychris; Mar 19, 2016 at 06:18 PM.
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Le Mans Master
Joined: Aug 2000
Posts: 6,486
Likes: 1,659
From: Las Vegas NV
NPP systems without any controllers or vacuum hoses attached are always OPEN.
This assumes the stock vacuum servo motors are still attached to the muffler tips (the servos have internal springs to keep the valves in the open position if no vacuum is applied). If the servos have been removed, the flaps will be loose to 'flap' open/closed at random.
Le Mans Master
Joined: May 2000
Posts: 7,033
Likes: 12
Yes as others have said it defaults to the loud mode, flappers open.
I have a set of modified Z06 mufflers on my car along with a complete Z06 exhaust. I did hook mine up so I could actuate the flappers. With that said I've closed mine off probably <10 times in the last 10,000 miles. I drive 30 miles ea way to work and in the morning 5 of those times is when I shut it off. I don't find the drone to be that bad, compared to Dynomax mufflers on my C4 it isn't anything. The drone from those things was very annoying.
For under $150 you can get a 3 way valve, brass fittings, hose, remote switch and an add a fuse and have it hooked up to operate if you want it to.
I have a set of modified Z06 mufflers on my car along with a complete Z06 exhaust. I did hook mine up so I could actuate the flappers. With that said I've closed mine off probably <10 times in the last 10,000 miles. I drive 30 miles ea way to work and in the morning 5 of those times is when I shut it off. I don't find the drone to be that bad, compared to Dynomax mufflers on my C4 it isn't anything. The drone from those things was very annoying.
For under $150 you can get a 3 way valve, brass fittings, hose, remote switch and an add a fuse and have it hooked up to operate if you want it to.
Race Director
Joined: May 2004
Posts: 16,667
Likes: 1,209
From: Raleigh, NC
St. Jude Donor '15
Yes, they are open if not connected to anything
The drone is HORRIBLE under 2K RPM's or so. Like, deafening sub woofer bass kind of drone. I do not recommend leaving them disconnected
You can hook them straight to a vacuum source and they'll stay shut until you give it some gas.
The drone is HORRIBLE under 2K RPM's or so. Like, deafening sub woofer bass kind of drone. I do not recommend leaving them disconnected
You can hook them straight to a vacuum source and they'll stay shut until you give it some gas.
Instructor
Joined: Sep 2006
Posts: 153
Likes: 4
From: Santa Maria Ca
After a long tour in 'Trash-Can-Istan' & getting blown up inside of V-shape hull MRAP vehicles multiple times, I have a constant BEEEEEEEEE in my ears & there's no P on the end...I have a hard time hearing what my wife says also. She says; Something, Something, Something, You're always, Something, Something, You never, Something, Something, Something, Why don't you, Something, Something, Something...That's what I hear anyways...lol 
Instructor
Joined: Dec 2014
Posts: 163
Likes: 5
From: Central AZ
I suspect, very strongly, you're not going to be happy with that system open all the time.. I've ridden in NPP cars when they are open, it's fun and sounds good cruising into a car show or at the drag strip.
But the constant drone at highway speeds is horrible. If you have headers, it's deafening as well.
But the constant drone at highway speeds is horrible. If you have headers, it's deafening as well.
Been there, done that, and didn't like it. Pilgrim
Burning Brakes
Joined: Aug 2011
Posts: 943
Likes: 9
From: Des Plaines IL
St. Jude Donor '12
One of the first and easiest mods I did was the dead pedal mild to wild switch and a muffler mod I did myself (got to t.i.g it) you'll never get used to that change in decibels!
Burning Brakes
Joined: Jun 2009
Posts: 1,065
Likes: 7
From: Madison, MS
I added them to my grand sport, and they stay open the whole time. The drone on the highway is not bad, as the sound they make all the time greatly outweighs the drone. I also drive with the windows, top off a lot.