Adding NPP to a non-NPP C6
Thread Starter
Advanced
Joined: Dec 2008
Posts: 86
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From: South Carolina
Adding NPP to a non-NPP C6
I have seen some older posts and threads with newer posts, but with dead links to product. Anyone have experience with doing this they can share? Looking at a C6 with NON NPP and would like to see how and how much $ it costs to do so.....also want to know how well the after market ones work.
Thanks!
Thanks!
Team Owner
Joined: Dec 2008
Posts: 35,874
Likes: 1,600
From: Honolulu HI
You can source some OE take off axle back mufflers with actuators on here most likely, or opt for something aftermarket like B&B Fusions...prices will vary depending on what route you take.
As for controlling the NPP exhaust, you simply need to install an "NPP in a Box" kit... https://www.southerncarparts.com/cor...st-p-2724.html
As for controlling the NPP exhaust, you simply need to install an "NPP in a Box" kit... https://www.southerncarparts.com/cor...st-p-2724.html
Race Director
Joined: Sep 2007
Posts: 16,557
Likes: 2,106
From: Peoria/Phoenix AZ
C6 of Year Finalist (performance mods) 2019
Enter "NPP in a Box" in the search box here and on the general forum. Most threads about converting a non-NPP optioned car to use a bi-mode muffler will have that term somewhere. After you've read till your eyes bleed, then come back here with the year and trans of the C6 you're looking at for more details.
Safety Car
Joined: Aug 2017
Posts: 4,243
Likes: 1,133
From: North Myrtle Beach SC
I was considering the same thing, even bought a pair of Z06 mufflers, then after thinking about the issues with the controller, etc, I ran across a great deal on a Borla S Classic axle back. Instead of having it very quiet sometimes and louder sometimes I now have something that sounds great ALL the time. My $.02
Race Director
Joined: Oct 2005
Posts: 14,555
Likes: 1,255
From: Saint Albans, WV
Tip clutter and two clean and two dirty (most I've seen) would be a deal breaker for me. The guys and gals that have them love them but they aren't for everyone. Cutouts may be a better option as they are FULLY adjustable, not a on/off switch.
Last edited by saplumr; Aug 29, 2018 at 01:41 PM.
Melting Slicks
Joined: Oct 2004
Posts: 2,863
Likes: 150
From: Woodland CA
My recommendation, get the NPP mufflers first and install them without NPP in a Box. My 2013 GS came stock with NPP and I honestly have it open 99.9% of the time. I spent money on the Mild2Wild controller when I could have just pulled the fuse. Oh well, lesson learned. After you get the NPP and you find that you want to be able to quiet it down from time to time, then you can pick up the NPP in a Box system. But if you like the sound of it open, save the money.
Someone correct me if I am wrong, but I believe if you have a 2005-2008 C6 you need to pick up the NPP mufflers from a 2008. If you have a 2009-2013 C6 you can use the NPP mufflers from 2009-2013 model. I believe it was in 2009 that GM changed the mid-pipe.
Racer
Joined: Jul 2014
Posts: 469
Likes: 44
I had an '06 automatic and retrofitted '08 bi mode axle backs. The bi mode axle back had 3" pipes, which I had cut off and the 2.5" from the '06 welded on. This was done due to clearance issues with the auto. You don't have to do that with a manuel trans.
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Drifting
Joined: Jun 2014
Posts: 1,431
Likes: 233
From: Chicago Illinois
I have an 06 base coupe. I am looking at an NPP axle back from a 2011 Grand Sport. I read somewhere that I would need to get my hands on the Mid-Pipe from a 2011 Grand Sport. I believe I got this bit of information from another thread on this forum. So, is there sometimes a need to swap out the mid-pipe as well as the NPP axle back?
Race Director
Joined: Sep 2007
Posts: 16,557
Likes: 2,106
From: Peoria/Phoenix AZ
C6 of Year Finalist (performance mods) 2019
I have an 06 base coupe. I am looking at an NPP axle back from a 2011 Grand Sport. I read somewhere that I would need to get my hands on the Mid-Pipe from a 2011 Grand Sport. I believe I got this bit of information from another thread on this forum. So, is there sometimes a need to swap out the mid-pipe as well as the NPP axle back?
Racer
Joined: Jul 2014
Posts: 469
Likes: 44
Originally Posted by HOXXOH
IIRC a little application of the thermal wrench (torch) will suffice for the right side. No need for the left side. The absolute worst case is to cut your current pipe off at the muffler and weld it on the NPP muffler, as it's a guaranteed fit.
Drifting
Joined: Jun 2014
Posts: 1,431
Likes: 233
From: Chicago Illinois
Racer
Joined: Jul 2014
Posts: 469
Likes: 44
Originally Posted by gpruitt54
So, the muffler shop did the work. How much direction did you have to provide to get the installation done right?
Drifting
Joined: Jun 2014
Posts: 1,431
Likes: 233
From: Chicago Illinois
Maybe I missed your description NPP vacuum system you used. Which system let you use the vacuum line from of the brake booster? The only such system I am aware of is the NPP in a Box. It uses a vacuum line from the rear of the intake manifold.
Racer
Joined: Jul 2014
Posts: 469
Likes: 44
Originally Posted by gpruitt54
Maybe I missed your description NPP vacuum system you used. Which system let you use the vacuum line from of the brake booster? The only such system I am aware of is the NPP in a Box. It uses a vacuum line from the rear of the intake manifold.
Race Director
Joined: Sep 2007
Posts: 16,557
Likes: 2,106
From: Peoria/Phoenix AZ
C6 of Year Finalist (performance mods) 2019
I had thoughts about just running tubing through the interior with a 1/4 turn valve as it passed by the driver's seat. The first version of the NPP in a Box used a vacuum pump that fit in the rear cubby and only needed a power source. When it died about a year later, they replaced it with the current version and I tapped into the IM with the hose.
Drifting
Joined: Jun 2014
Posts: 1,431
Likes: 233
From: Chicago Illinois
A DIY NPP in a Box. Cool! You should show what you did along with a description of the project details.
Racer
Joined: Jul 2014
Posts: 469
Likes: 44
Originally Posted by ExxWhy
Is there a T fitting available to use to tie into the brake booster? What size is that hose? Trying to avoid the manifold fitting on my LS3. I already have the scratches from trying! 