Another exhaust question
Thread Starter
Navigator
Joined: Feb 2026
Posts: 9
Likes: 3
From: Central IL
Another exhaust question
When I bought my C6 it already had headers, no cats, and Corsa exhaust. It's louder than I like, I'm not a fan of the smell, and the decel "burbling" is excessive and annoying. I'm going to start with a tune to make sure that the previous owner didn't have a "burble tune" done. After that how much of a sound/smell/burble reduction would I expect from installing kooks green cats vs going with Borla touring axle back?
Advanced
Joined: Oct 2020
Posts: 91
Likes: 33
From: Missouri
Ill Trade you my stock LS3 manifolds, cats, and factory X-Pipe for your headers and Aftermarket X-Pipe... I already have Corsas and I can say that mine is very tame with little burbles... Ill trade you straight across lol
Intermediate
Joined: Sep 2025
Posts: 28
Likes: 22
The green cats will help tone the exhaust note down a bit, the smell will be gone as well. Going with the touring exhaust will also quiet it down but if you stay catless it'll still be on the loud side. You should go with the NPP factory exhaust and do the mild 2 wild switch. You'll have best of both worlds, nearly silent with valve shut and rowdy when they're open. I have long tubes, catless x pipe and the npp exhaust on my Grand Sport with a BTR stage 2 camshaft and with the values shut it's nearly silent.
Supporting Vendor
Joined: May 2018
Posts: 5,218
Likes: 411
From: Philadelphia
Do you know which brand headers? Adding a catted x-pipe will definitely tone things down in regards to volume and smell.
The popping on decel that you're experiencing is unburnt fuel igniting in the exhaust.
Happy to help with any Kooks/ARH products
- Alec
267.788.4897
The popping on decel that you're experiencing is unburnt fuel igniting in the exhaust.
Happy to help with any Kooks/ARH products
- 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!
Thread Starter
Navigator
Joined: Feb 2026
Posts: 9
Likes: 3
From: Central IL
The green cats will help tone the exhaust note down a bit, the smell will be gone as well. Going with the touring exhaust will also quiet it down but if you stay catless it'll still be on the loud side. You should go with the NPP factory exhaust and do the mild 2 wild switch. You'll have best of both worlds, nearly silent with valve shut and rowdy when they're open. I have long tubes, catless x pipe and the npp exhaust on my Grand Sport with a BTR stage 2 camshaft and with the values shut it's nearly silent.
Thread Starter
Navigator
Joined: Feb 2026
Posts: 9
Likes: 3
From: Central IL
Do you know which brand headers? Adding a catted x-pipe will definitely tone things down in regards to volume and smell.
The popping on decel that you're experiencing is unburnt fuel igniting in the exhaust.
Happy to help with any Kooks/ARH products
- Alec
267.788.4897
The popping on decel that you're experiencing is unburnt fuel igniting in the exhaust.
Happy to help with any Kooks/ARH products
- Alec
267.788.4897
Thread Starter
Navigator
Joined: Feb 2026
Posts: 9
Likes: 3
From: Central IL
That's very generous. Thank you for the offer. Lol
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How long have you had it? My car does but lea and pops on deceleration and it's totally stock. It's just part of a performance car of this era. Yours having long tubes and mods is only going to have it more so.
If you want to quiet it down and get rid of the smell, just go back to stock. That's probably going to cost a fair bit of you can't do the work yourself.
If you want to quiet it down and get rid of the smell, just go back to stock. That's probably going to cost a fair bit of you can't do the work yourself.
Thread Starter
Navigator
Joined: Feb 2026
Posts: 9
Likes: 3
From: Central IL
How long have you had it? My car does but lea and pops on deceleration and it's totally stock. It's just part of a performance car of this era. Yours having long tubes and mods is only going to have it more so.
If you want to quiet it down and get rid of the smell, just go back to stock. That's probably going to cost a fair bit of you can't do the work yourself.
If you want to quiet it down and get rid of the smell, just go back to stock. That's probably going to cost a fair bit of you can't do the work yourself.
Burning Brakes
Joined: Apr 2023
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From: Florida
2025 C6 of the Year Finalist - Unmodified
You can tune the dfco (deceleration fuel cutoff) entry and exit timing so it doesn’t pull as much timing on decel hence less popping and gurgling. Stock tune without cats on my ls2 even had lots of pops on decel.
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From: Pittsburgh
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Those Kooks green cats are a quality product & will remove any nasty smells, they are expensive but "you get what you pay for"
Melting Slicks
Joined: Dec 2003
Posts: 2,340
Likes: 722
From: Chicago N/W Suburbs
When I bought my C6 it already had headers, no cats, and Corsa exhaust. It's louder than I like, I'm not a fan of the smell, and the decel "burbling" is excessive and annoying. I'm going to start with a tune to make sure that the previous owner didn't have a "burble tune" done. After that how much of a sound/smell/burble reduction would I expect from installing kooks green cats vs going with Borla touring axle back?
Thread Starter
Navigator
Joined: Feb 2026
Posts: 9
Likes: 3
From: Central IL
I read that post as well and thought the same thing. The price I paid for mine was about $6k to $8k less than comparable stock cars, so I figured in a possibility of having to spend up to $6k on unknowns. I'm going to start with a tune (just because I don't know who tuned it before) and kooks cats, then go from there as I still want louder than stock, I just want to tame it down.
Thread Starter
Navigator
Joined: Feb 2026
Posts: 9
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From: Central IL
Supporting Vendor
Joined: Nov 2015
Posts: 1,262
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From: Orange County, NY
Hit the brakes OP. First of all what model of C6 is it and what year is it? Please fee free to text me photos of your headers + xpipe plus mufflers/axleback/tips so I can determine what exactly is on the car. From there I can recommend solutions to your excessive snap crackle pop.
Call or text 201-575-0861
Sincerely,
Ciro
Call or text 201-575-0861
Sincerely,
Ciro
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sales@corvetteexhaustsystems.com
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sales@corvetteexhaustsystems.com
201-575-0861 (cell to call or text)
Your Ultimate Resource For Headers, Exhaust Systems & more for Corvette! I carry Corsa, Kooks, ARH, Borla, Billy Boat, Akrapovic, Capristo & Much More
8th Gear
Joined: Feb 2021
Posts: 8
Likes: 1
From: Tucson Arizona
will base model NPP mufflers fit on my c6z06?
Stupid question but will base model NPP mufflers fit on my c6z06?
im in the same boat. I took the stock exhaust system off my z06 years ago. The smell and sound did not bother me at first but now it does. I plan on getting the green cats and putting the stock NPP mufflers on. Found some for $100 bucks on the marketplace. Just want to make sure they will fit before I buy them.
im in the same boat. I took the stock exhaust system off my z06 years ago. The smell and sound did not bother me at first but now it does. I plan on getting the green cats and putting the stock NPP mufflers on. Found some for $100 bucks on the marketplace. Just want to make sure they will fit before I buy them.
The green cats will help tone the exhaust note down a bit, the smell will be gone as well. Going with the touring exhaust will also quiet it down but if you stay catless it'll still be on the loud side. You should go with the NPP factory exhaust and do the mild 2 wild switch. You'll have best of both worlds, nearly silent with valve shut and rowdy when they're open. I have long tubes, catless x pipe and the npp exhaust on my Grand Sport with a BTR stage 2 camshaft and with the values shut it's nearly silent.
Supporting Vendor
Joined: Nov 2015
Posts: 1,262
Likes: 278
From: Orange County, NY
Stupid question but will base model NPP mufflers fit on my c6z06?
im in the same boat. I took the stock exhaust system off my z06 years ago. The smell and sound did not bother me at first but now it does. I plan on getting the green cats and putting the stock NPP mufflers on. Found some for $100 bucks on the marketplace. Just want to make sure they will fit before I buy them.
im in the same boat. I took the stock exhaust system off my z06 years ago. The smell and sound did not bother me at first but now it does. I plan on getting the green cats and putting the stock NPP mufflers on. Found some for $100 bucks on the marketplace. Just want to make sure they will fit before I buy them.