Exhaust
Thread Starter
Heel & Toe
Joined: Oct 2024
Posts: 24
Likes: 1
From: Sikeston
Exhaust
Can you replace the factory mufflers with aftermarket mufflers and not mess with the factory npp? I would like more sound and still have the ability to select the exhaust mode.
Safety Car
Joined: Dec 2012
Posts: 3,841
Likes: 1,856
From: St. Louis Metro East IL
I don't think so unless the new mufflers have NPP valves.
The factory NPP valves are integral to the muffler assembly. The NPP valve is welded into the straight pipe (left pipe in the pic below)
Ron
The factory NPP valves are integral to the muffler assembly. The NPP valve is welded into the straight pipe (left pipe in the pic below)
Ron
Le Mans Master
Joined: Jun 2019
Posts: 5,445
Likes: 2,167
From: Loveland
This is good. I love it. Easy to install, sounds great, not crazy expensive. These don't change the NPP and does eliminate the secondary, useless cats.
https://extremeonlinestore.com/produ...kaAiLtEALw_wcB
https://extremeonlinestore.com/produ...kaAiLtEALw_wcB
Last edited by kodpkd; Aug 29, 2025 at 02:03 PM.
Supporting Vendor
Joined: May 2018
Posts: 5,215
Likes: 411
From: Philadelphia
You can do a vavled system like Corsa or Borla that will retain the valved NPP functionality.
Headers w/X-Pipe and OEM NPP is a better ROI in my opinion, for power and volume gains.
Feel free to reach out with any questions or if you'd like pricing on any options.
- Alec
267.788.4897
Headers w/X-Pipe and OEM NPP is a better ROI in my opinion, for power and volume gains.
Feel free to reach out with any questions or if you'd like pricing on any options.
- Alec
267.788.4897
__________________
Alec @ Forza Motor Works
(267) 788.4897 Call/Text
info@forzamotorworks.com
www.forzamotorworks.com
Your trusted source for premium parts - offering competitive pricing, exceptional service, and professional installation options.
Corsa | Borla | AWE Tuning | Girodisc | Halltech | American Racing Headers | Milltek | Soler | Weld | Fabspeed | SOUL | Kooks | BC Forged & 100's more!
Alec @ Forza Motor Works
(267) 788.4897 Call/Text
info@forzamotorworks.com
www.forzamotorworks.com
Your trusted source for premium parts - offering competitive pricing, exceptional service, and professional installation options.
Corsa | Borla | AWE Tuning | Girodisc | Halltech | American Racing Headers | Milltek | Soler | Weld | Fabspeed | SOUL | Kooks | BC Forged & 100's more!
Le Mans Master
Joined: Jun 2016
Posts: 5,413
Likes: 3,957
From: Cincinnati, OH
You can do a vavled system like Corsa or Borla that will retain the valved NPP functionality.
Headers w/X-Pipe and OEM NPP is a better ROI in my opinion, for power and volume gains.
Feel free to reach out with any questions or if you'd like pricing on any options.
- Alec
267.788.4897
Headers w/X-Pipe and OEM NPP is a better ROI in my opinion, for power and volume gains.
Feel free to reach out with any questions or if you'd like pricing on any options.
- Alec
267.788.4897
Supporting Vendor
Joined: Nov 2015
Posts: 1,260
Likes: 278
From: Orange County, NY
If you don't want to mess with emissions components do a valves axleback, like the Corsa or Borla valved options. Me personally I don't see a need for a valve when running a Corsa Xtreme or AWE Touring. I'd be happy to go over options, pricing & availability @Cowboy Corvette 69
