4SUMERZ

They would likely stay in place if they have to be pounded on the hole.
Because of our laws about holes or leaks in an exhaust system to pass yearly inspections, I had metal welded over the hole, grinded smooth and painted the same black color as OEM. Can't tell that there was ever a hole there.
Any one with a home welder can do in in minutes.

needdlex

My father-in-law is a welder and I help him on the weekends. I've never touched stainless, but it's 2nd nature to him.

Oklahoma doesn't require emissions or inspections (or mufflers). Did this for two weeks on a C5 and it was amazing, but gave me headaches.

If welding is definitely the best option, I won't bother with the plugs. It's only a couple of miles (and free) for me to get it welded.

kenoverbey

All of the sound videos and how to's aren't playing. Does anyone have any recent vids that show exactly where to drill and the sound before and after. Thi sounds like a great mod. I had an 05 with the magnaflow and loved that sound. The corsa is too crackly for me. The stock sounds like a damn mini van....

Gary7

If installed correctly, the plugs are not going to fall out (if that's what you're worried about). You have to use a hammer to knock them in and it takes some work with a screwdriver to pry them out.

kenoverbey

I did the muffler mod last night with a 1" hole saw. It took me all of 20 minutes! It sounds so much better. Cost me a whopping $1.87.

Professor2006

Did the muffler mod yesterday with a 3/4" hole saw. Took less than an hour and sounds really good. Much more throaty at idle, and mellow roar on acceleration. Bit of a hum at around 1500 rpm, but not obtrusive.
Closed up one hole with a 1/2" knockout cover, but for the life of me could not get the other one to stay in. Ended up making a patch out of an old license plate and pop riveting it on. Sealed all with some Permatex Muffler and Tailpipe Sealer that I had laying around.
Well worth the time!

jakemacaw84

I actually did a 3/4" hole on mine, they sounded great. I was to lazy to patch the hole back up after the cut, I just let it dump straight out of the muffler. NONE of my friends knew I didn't get an actual after market exhaust.

DON'T kid yourself in thinking this makes it loud. It adds a better tone, and slightly more volume. That's about it. But at least it sounds more like a car that makes 400+ hp. Recently just picked up a Borla xpipe and catback system, (S-type) and man was it way better. However the muffler mod held me over for months. I finally needed to be heard though and got the Borla and TSP Headers.

Kevjud

Did the mod today. I just ended up using a 3/4" hole saw and drilled through the outer can and both sides of the inner pipe. Pretty easy to do as you can eyeball it and see where the inner pipe is because it is close to the exit pipe. I found some cool knockouts at Menards. They worked great.

mike_engr

A few days ago I got a C6 Vert (just listed my C5 Vert 49k miles on CL). I wanna do the C6 muffler Mod. Maybe start with 3/4" hole thru outer shell and 1 side of pipe inside. Then incrementally add hole diameters on 2nd side of pipe to tune the sound to my liking???

My concern involves actual location of the Shell pilot hole????
I understand that we draw an imaginary line inward following the line of sight of the muffler exit pipe, but how far inward from the back of the muffler do we drill our pilot hole? Anyone have a measurement for that? Maybe 1.5" ??? 2"???

Also, it seems like we are aft of the center chamber, so we can't reach its fiberglass packing for removal? True?

Thanks for any advice on this....

PS: Also, is the best angle for the hole straight Vertically up from bottom? Or should the drill come in more from the middle or outside of the car? I assume same on both sides?

kenoverbey

I wouldn't waste my time on 3/4 " and one hole in the pipe... I did 1" and through both sides of the pipe and barely noticed a difference.

HammerheadTed

If you look at Kevjud post showing his knockouts, you can estimate the distance. That's about where I did mine and similar to the many pics on this thread. You don't want to get too far from the end of the case. There is a partition inside the muffler.

Cars6523

I started at 1/2" than went to 1". Defiantly has a little more sound.

Drove it for a while and wanted more so I went to 1-1/4".

1-1/4" should be about 55% more area than a 1". I noticed no difference over the 1" so I would say that this mod is only good up to a point.

Great advice from all involved here and defiantly happier with this mod over stock and at practically no cost.

Thank you all

jaredtxrx

I did this mod about a month ago. Wow, I wish I would have come back to this thread to see those knockout things instead of what I did do. That looks great.

At any rate, I went with 1" all the way through, here are before and after sound clips.
Before

After

cstapp99

I did this mod a while back with 1/2" holes through and through. I capped and sealed the exterior hole. Since then, I've added TSP long tubes with off-road 3" x-pipe. The mod was pretty nice with the stock exhaust, but with headers, dang it wakes up!

jmeirhofer

I am looking at doing this in the near future as well. Adding the hitch to mine has limited the options a bit for exhaust.

Rusler John

What type of hole saw are you using? I'm assuming it needs a long shaft and made to cut metal.

cstapp99

I used a Lennox brand hole-saw for cutting metal. The body of the saw blade is around 2 1/2" long.

LoganExplosion

Exactly!! Then why are you modding like them?

jaredtxrx

http://www.homedepot.com/p/Milwaukee...9662/202327732

cstapp99

The question doesn't really deserve a response, but I'll bite. Although I'm far from a broke teenager, I have never lost my sense of value. To me, not a single axle-back exhaust system available for the vette is worth half of what they ask for them. That being the case, an easy and visually non-detectable modification to the stock system which costs next to nothing and yields good results was a no-brainer for me.

Now I will say that some of the mods I see are a bit ridiculous. When I bought my car, the previous owner had put chrome mesh inside the fender gills and lined the gills with chrome trim (black car.) That crap had to go.