M3 exhaust modification

[abugiacomo]

Has anyone ever tried simply pulling out the stuffing and leaving the perforated pipes as is? Someone suggested that this would result in a very raspy sound but I've never heard of anyone actually trying it to see for sure.

[Bubbles]

Originally Posted by CFM3

Is there any potential downside to this mod, such as would covering the perforation impact heat dissipation?

Tracked with mod. No heat issues whatsoever, in 85f temps.

In fact, I think the trunk is much cooler than before, the exhaust doesn't make a stop in the absorption chamber.

[snowmants]

Originally Posted by Bubbles

Tracked with mod. No heat issues whatsoever, in 85f temps.

In fact, I think the trunk is much cooler than before, the exhaust doesn't make a stop in the absorption chamber.

Valid Point.... i dont think there is any real downside to this mod, and the only upside seems to be sound. I dont think there is any meaningful performance gain that I have noticed. It sounds great!

[CallMeWonder]

How do you tell which side to cut open to easily access the larger perforated pipes?

thanks, scheduled to do this friday.

[808elise]

This post motivated me to go in and get this done today after reading it late yesterday. Once I got there we ended up cutting out section three all together and adding straight pipes and glass pipes. I love it. Its even easier and great way to save a lot of weight.

[CallMeWonder]

Got this done today and all I can say is wow! Sounds incredible!

Got it done for 300 which is great!!


Thanks everyone for the inspiration.

[Big Mark]

Originally Posted by jdz724

hey bigtex. where in dfw were you about to find a shop to do this. I called around and couldnt get anyone to do it for a decent price

I got this done today at the place bigtex found. It's called b&g muffler in grapevine (817.481.2298, Jeff). They charged $300 and I'm pretty happy with it. I had them cover the larger pipes but not the small ones. They cut into the top of the muffler so theres less visual evidence of the mod. Somewhat louder but not too much. Just right for a daily driver so I don't piss off the neighbors or wife.

[bigtex]

^ happy you like it. For whatever reason mine got a bit louder about 2 weeks later. Let me know if the sound of yours changes too. My favorite rpm range is between 3-4.5k...music to my ears.

[IbanezGod]

honestly it sounds just like OEM... i can't tell a difference. However the autocouture mod is much louder.

Now this OEM mod i can tell a huge difference!

http://www.m3post.com/forums/showthr...EM+Exhaust+mod

[0-60Motorsports]

Awesome Mod!

[Subw00er]

Some sweet mods in here.. Lets see more valve exhausts though.

[stocksure]

I had the exhaust mod PicassoM is referring to done by a local shop. The exhaust is now much louder. It was definitely worth it.

[Robmaster]

hey guys. found this at a german M Forum. a shot of the inside of a BMW Performance exhaust:

[bigjae1976]

This might be a stupid idea. If we do the straight through pipes like the picture 2 posts above, can we just seal off the old pipe going through the middle and just lose the center of the can? And you can relocate the stuffing to the outer sections to add a little bit of sound deadening.

So it will be 2 separate and smaller cans. You will need to make some new hangers but I don't see any other issues. Unless the

[tibra1]

Read this whole thread..alot of good info..came across this video where a shop in Canada did it and took dB readings..I also like the way they opened the exhaust from the top so that once re-installed nothing would show..this is def gonna be my first mod

[gerritg]

love it. I did this to my SLK55 AMG exhaust for 300 bucks and this is the best ever mod. I totall agree with you. U just need experienced people.

[Subw00er]

Originally Posted by tibra1

Read this whole thread..alot of good info..came across this video where a shop in Canada did it and took dB readings..I also like the way they opened the exhaust from the top so that once re-installed nothing would show..this is def gonna be my first mod

Thats a cool vid.

Maybe this is interesting.. I did some DB tests too with my valves open and closed.. looks like mine are a dB few louder, which makes sense because mine split out before the center section.

If you look at my YouTube channel, there is another video with in-car dB readings.

[bigjae1976]

Originally Posted by tibra1

Read this whole thread..alot of good info..came across this video where a shop in Canada did it and took dB readings..I also like the way they opened the exhaust from the top so that once re-installed nothing would show..this is def gonna be my first mod

Wow! 90db to 93db is significant...even more sold on doing this.

[uplusd]

Originally Posted by tibra1

Read this whole thread..alot of good info..came across this video where a shop in Canada did it and took dB readings..I also like the way they opened the exhaust from the top so that once re-installed nothing would show..this is def gonna be my first mod

Thanks for this video! It really helps detail the process.

[1sikbmr]

Originally Posted by bigjae1976

This might be a stupid idea. If we do the straight through pipes like the picture 2 posts above, can we just seal off the old pipe going through the middle and just lose the center of the can? And you can relocate the stuffing to the outer sections to add a little bit of sound deadening.

So it will be 2 separate and smaller cans. You will need to make some new hangers but I don't see any other issues. Unless the

This is very possible but at the same time the two separate cans might look retarded. I guess it is all up to the shop doing the fab work to make it look decent. It is a very good weight saver and shouldn't drone because it is essentially the same thing as having it sealed up.

[bigjae1976]

Originally Posted by 1sikbmr

This is very possible but at the same time the two separate cans might look retarded. I guess it is all up to the shop doing the fab work to make it look decent. It is a very good weight saver and shouldn't drone because it is essentially the same thing as having it sealed up.

What I'm reading is that the ACM version does drone a tad. I'm guessing that the middle section of the muffler where the pipes cross is what kills the drone???

[1sikbmr]

Originally Posted by bigjae1976

What I'm reading is that the ACM version does drone a tad. I'm guessing that the middle section of the muffler where the pipes cross is what kills the drone???

not really. The part where the pipes enter the exhaust from the back(that's what she said) is where the helmhot's chamber is. if you look at the exhaust when it is open you will see it. But drone to some is none to others.