C6 muffler mod...FAILED
Thread Starter
Heel & Toe
Joined: Dec 2015
Posts: 24
Likes: 7
From: Los Angeles CA
C6 muffler mod...FAILED
When I first got my C6, it was too quiet for me. So I did the famously muffler mod where one drills through the muffler and internal pipe and it increases the sound. I had it like this for about 1 year.
After searching for an advance mod of this type, I figured just cut the insides and weld the muffler shell back in place, so I did that.
Here is where the fun begins. Sheet metal is so easy to cut through when welding it. I have never welded sheet metal and found it very difficult to weld. After what seems hours to me, I finally got a good weld, went over it twice and I thought I was good to go. Well, when I applied soapy water and pumped about 20psi of compressed air to check for leaks, there were bubbles everywhere!
I pulled the cat back, cut the mufflers off and went to a muffler shop. The only muffler they were able to fit in there were the Flowmaster Super 10's. To my surprise, it sounded amazing.
Moral of the story, plan for a back up when modding your car. Stuff happens!
After searching for an advance mod of this type, I figured just cut the insides and weld the muffler shell back in place, so I did that.
Here is where the fun begins. Sheet metal is so easy to cut through when welding it. I have never welded sheet metal and found it very difficult to weld. After what seems hours to me, I finally got a good weld, went over it twice and I thought I was good to go. Well, when I applied soapy water and pumped about 20psi of compressed air to check for leaks, there were bubbles everywhere!
I pulled the cat back, cut the mufflers off and went to a muffler shop. The only muffler they were able to fit in there were the Flowmaster Super 10's. To my surprise, it sounded amazing.
Moral of the story, plan for a back up when modding your car. Stuff happens!
Melting Slicks
Joined: Oct 2011
Posts: 2,992
Likes: 394
From: Naples FL
2023 C6 of the Year Finalist - Modified
2022 C6 of the Year Finalist - Modified
2021 C6 of the Year Finalist - Modified
2020 C6 of the Year Finalist - Modified
2015 C6 of Year Finalist
If I said what I am thinking the moderators would ban me on here for life!
CF Community Team
Joined: Apr 2016
Posts: 14,146
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From: Pittsburgh
2025 C6 of the Year Finalist - Unmodified
2024 C6 of the Year Finalist - Unmodified
2023 C6 of the Year Finalist - Unmodified
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2021 C6 of the Year Finalist - Unmodified
That muffler mod on a Corvette?
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Thread Starter
Heel & Toe
Joined: Dec 2015
Posts: 24
Likes: 7
From: Los Angeles CA
Simply because I was bored. I'm a big DIY'er, so I'm always thinking outside the box. I won't always get the best results, and I'm ok with that. Some lessons can be expensive though.
I originally wanted to go with Corsa Extreme but they are way too expensive. I wanted to pair them up with the Kooks headers but that would mean going back to stock every 2 years for smog. The way I look at it is, if I didn't like the way these turned out, I could simply go back to stock. Stock axle backs go for around $70-100 around here.
Team Owner
Joined: Jun 2005
Posts: 46,295
Likes: 2,596
From: Northern, VA
St. Jude Donor '15
"In honor of jpee"
I think I get it: I think Boomer is correct. The OP was, like most of us, just demonstrating some of the not-so-great ideas we all try out. I have so many like his, mainly because I'm not the handiest person in the world. And I don't always have the exact, perfect piece of equipment which I would like to blame for most of my boo-boos 
.
But, it's hard to blame tools or equipment when someone takes plastic taillights, glues them perfectly from their cracked-up condition, then decides to "cure" them in the oven at 350*----only to see them warp as only plastic can do! I'm not saying who did this, but he's typing right now. Thankfully, it was a long time ago.
. But, it's hard to blame tools or equipment when someone takes plastic taillights, glues them perfectly from their cracked-up condition, then decides to "cure" them in the oven at 350*----only to see them warp as only plastic can do! I'm not saying who did this, but he's typing right now. Thankfully, it was a long time ago.
Pro
Joined: Oct 2014
Posts: 616
Likes: 193
From: Gilbert AZ
From the description, it sounds like the OP used a MIG or maybe even a stick welder and way too much current to try and patch the muffler. If you are an experienced weldor, with the right equipment, MIG is possible, but if the mufflers are stainless, you really need to weld this with TIG.
I'd use about 40A, .045 stainless filler rod, and shield with 100% argon. And the muffler surface would need to be cleaned up much better before getting out the torch.
Garry
I'd use about 40A, .045 stainless filler rod, and shield with 100% argon. And the muffler surface would need to be cleaned up much better before getting out the torch.
Garry
Pro
Joined: Jun 2015
Posts: 729
Likes: 97
From: Lancaster NY
The first thing I did when I bought my Vette was the muffler mod. I wasn't happy with it and was thinking about doing the same as the OP but thankfully I found a killer deal on NPP mufflers that were a direct fit! Glad I found them or I probably would have posted a similar outcome to my DIY! 
Burning Brakes
Joined: Oct 2009
Posts: 962
Likes: 61
From: oswego ny
The first thing I did when I bought my Vette was the muffler mod. I wasn't happy with it and was thinking about doing the same as the OP but thankfully I found a killer deal on NPP mufflers that were a direct fit! Glad I found them or I probably would have posted a similar outcome to my DIY!
Racer
Joined: Feb 2006
Posts: 393
Likes: 72
From: VA
just follow the pics. Lift helps but can be done with ramps and safe jack stands. mellow sound so you can hear the engine running. Not a Corsa, but works and simple to do.
Burning Brakes
Joined: Jan 2017
Posts: 1,122
Likes: 199
From: TX
Le Mans Master
Joined: Sep 2014
Posts: 7,001
Likes: 988
From: lake havasu city arizona
I remember as a youngster we tried all kinds of stuff to our bikes, 2x4's with skates nailed to them for example, and then our cars (jalopies) because we didn't know any better and were broke.
Maybe we regress as we grow older
NSF
Maybe we regress as we grow older
NSF