M3 exhaust modification

[sig5x]

Interesting - please let us know how it goes! I'm sure many will be curious about sound and any power gains.

[paul walker]

Trying to locate a stock e90 M3 muffler right now and having some trouble, don't want to have downtime leaving my car up on the hoist at the shop

[kcdude24]

Are you thinking of solid or perforated piping to a single exit pipe? You also might consider leaving the center chamber unblocked by cutting out the pipes and leave the holes in the chamber walls...then just pack it to absorb some of the sound...otherwise it looks hella loud with a solid straight pipe.

[paul walker]

I'm looking to block off the center baffled area, use the perforated pipe on the single exits and packing those with the existing sound dampening material from the middle baffles, should make it good to go, if it's not loud enough I'll rip it apart again and weld in straight pipes and remove all the sound dampening but it should be plenty loud with the dampening material in there and perforated pipes but have similar gains to that of a aftermarket. I should do a before and after dyno

[kcdude24]

Originally Posted by paul walker

I'm looking to block off the center baffled area, use the perforated pipe on the single exits and packing those with the existing sound dampening material from the middle baffles, should make it good to go, if it's not loud enough I'll rip it apart again and weld in straight pipes and remove all the sound dampening but it should be plenty loud with the dampening material in there and perforated pipes but have similar gains to that of a aftermarket. I should do a before and after dyno

Man I wish someone would also sell and ship me their used unit to try this. Very interested to see and hear the results. I'll be curious to see how much the modified setup drones compared to the OEM setup....if that center section is blocked off completely that thing may drone lika a mofo. Then again the side chambers are just like the Eisenmann units...this may work really well and you can tune the sound to your liking with perf pipes and packing. I do notice that the EIsenmann units still have connecting pipes between the chambers....I assume this is to reduce drone/weird resonances.

[CNDM3]

Here is my car, exhaust with all the holes wrapped and stuffing still in the muffler. Best $20 mod I've ever spent on a car. Love the sound, it will hold me over until I can afford a straight piped G-car


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Good launch at the beginning

[ferrari6891]

has anyone posted a proper DIY for this?
p.s. props to Perio and everyone else who did this...very creative!

[GewoW]

Ok guys I want to do this, but I only want to minimally increase sound over stock. Basically, if I keep bigfoot inside, as well as the metal wiring/mesh around the smaller perforations, and then weld only HALF the long perforated pipe, what can I expect in terms of sound level increase?

Can someone SPL measure their exhaust?

[Subw00er]

I'm just catching up with this thread. Some neat ideas in here! (Here was mine:
http://www.m3post.com/forums/showthread.php?t=253661 )

To the fellow (Paul) who was going to use straight pipes- they wont be straight, you're going to have to bend them up or down depending on the side to make that work.

To the fellow interested in SPL measurements, I did some after I modded mine.

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[GewoW]

Originally Posted by Subw00er

I'm just catching up with this thread. Some neat ideas in here! (Here was mine:
http://www.m3post.com/forums/showthread.php?t=253661 )

To the fellow (Paul) who was going to use straight pipes- they wont be straight, you're going to have to bend them up or down depending on the side to make that work.

To the fellow interested in SPL measurements, I did some after I modded mine.

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hey thx so much for this. Lemme ask you - how far was the mic? do you think from your experience i'd be under 93db from 50 ft away?

[Subw00er]

The mic was maybe 10 feet away if I recall. I think I called upon the standard distance for measuring exhaust DB. My Bates Exhaust post has the distance in there if you want to dig for it. I am not sure what the # would be - there are many factors...

[GewoW]

Originally Posted by Subw00er

The mic was maybe 10 feet away if I recall. I think I called upon the standard distance for measuring exhaust DB. My Bates Exhaust post has the distance in there if you want to dig for it. I am not sure what the # would be - there are many factors...

it was 6 ft. I just checked. so if it was 93ish db at 6' at ~4500-5000, then 50ft 93 db @ 6300 SHOULD be OK

[Emil]

First of all I would like to thank periokid and all other contributers for supporting so much invaluable information on the exhaust modification.
I had my muffler modified this week and it was installed yesterday.
I am very pleased with the result! As others mentioned before, there is definitely no drone. The cars quality as daily driver is in no way reduced, which was very important for me.

The tone of the system is a little more on the agressive side, sounds a little more throaty than before and gained in volume very noticeably but not annoying. The sound of the dct changing gears is much more pronounced now and there is also a little backfire

We opened the can from the top side so the mod is nearly invisible now that the system is installed again. As most of you did, we cut out the large perforated pipe and left the other pipe with the small perforated section just as it is.
After welding in a closed stainless steel tube all the wool was stuffed back into the chambers and the cabinet was rewelded.

I took some pictures as well but the are not very different from the ones that were already published here.

Cheers,
Jochen

[kmarei]

just installed another modded OEM exhaust
wow
sounds amazing
only the larger perforated pip was repalced with solid pipe
i love it!
i have a spare OEM now if someone local wants it

[Bx Tpr]

I've got an oem E90 muffler available in NYC.

[birgppa]

how much are you guys paying for a used oem muffler in the states?

[Subw00er]

$150 I think..

[birgppa]

Originally Posted by Subw00er

$150 I think..

Great.... payed 800 for one. Only found one tho, small country 7000 miles.

[Subw00er]

That seems steep. It did cost me $100+ to ship it though.. its a weird item to sell.. basically no market for them unless there is an accident or someone wants to mod one. Forums are probably the best place to find one.

[JCtx]

Originally Posted by GewoW

Ok guys I want to do this, but I only want to minimally increase sound over stock. Basically, if I keep bigfoot inside, as well as the metal wiring/mesh around the smaller perforations, and then weld only HALF the long perforated pipe, what can I expect in terms of sound level increase?

I'm on the same boat, and that (in bold) is EXACTLY what I was going to ask, so you beat me to it buddy . Has anybody done this???

Reason I thought of that myself was after somebody with just a modded exhaust (kcdude?) said it was too loud outside, and neighbors weren't pleased. Half of the larger perforated pipe might do the trick IMO. But the question now is if you could cut the piece right in the middle, making the job easier (but leaving 2 small perforated sections separated by solid tubing), or cut from beginning to half on either side. Comments welcome.

[Poppin Fresh]

Why not just plug up the pipes with the smaller perforations and leave half off the insulation wool inside?

[JCtx]

Originally Posted by Poppin Fresh

Why not just plug up the pipes with the smaller perforations and leave half off the insulation wool inside?

All the insulation needs to be there, or it'd sound raspy as hell. But just covering the smaller pipes might be a solution too. Need to see the pics for access though; don't remember if they're easier to harder to get at. Good suggestion man .