OEM Exhaust Perf Mod

[Ron1n]

Got this done (not the ACM version, but the actual 2 perf pipe version), and I'm super happy. The guys that did the work did an excellent job (wish I could weld, because I would have done this myself).

Check it out. Video is in 4k. I'll try and get a better audio pull from the car soon.

[Fizik]

Sounds great, same mod I did to mine a couple years ago.

[mrMTB]

Do you mind sharing what they charged? Looks like I can get their phone number from the vid.

[Ron1n]

Originally Posted by mrMTB

Do you mind sharing what they charged? Looks like I can get their phone number from the vid.

Expect to spend around $375 or so (which is half of what I found for anywhere else that I asked to do the work).

It's the cheapest exhaust mod you'll ever do that improves the audio quality.

And tell them Ryan with the M3 sent you (no, I don't get anything from it, but it will help them know what you're looking to do).

Isaac can do the work.

[Ricfutures]

Sounds great! Any drone?

[Fizik]

Originally Posted by Ricfutures

Sounds great! Any drone?

I don't get any on mine. It's a great exhaust. Almost stock at idle and under 2k rpm. After about 3k you can really hear the difference.

[sterile stork]

Sounds great, but for good heavens, rotate the phone 90-degrees when recording video

The exhaust setup you have reminds me of my white E92:

[Ron1n]

Originally Posted by Ricfutures

Sounds great! Any drone?

No drone at highway speeds (70ish). Go higher than that and you'll catch some, but that's to be expected.

[Ron1n]

Originally Posted by sterile stork

Sounds great, but for good heavens, rotate the phone 90-degrees when recording video

The exhaust setup you have reminds me of my white E92:

YT is supposed to autorotate so that shit doesn't happen. I don't know what the darn issue was.

[yongj]

How long did the process take? Hopefully not days? I'm coming from Tacoma so I don't want to make multiple trips.

[Ron1n]

Originally Posted by yongj

How long did the process take? Hopefully not days? I'm coming from Tacoma so I don't want to make multiple trips.

4 hours for mine, but that's because I had to show them what to do (they were unfamiliar with this particular mod on our cars). I'm certain the next time around will be much better. We also found a way to do it a bit faster when working on mine. Multiple days isn't even a possibility.

[yongj]

Originally Posted by Ron1n

4 hours for mine, but that's because I had to show them what to do (they were unfamiliar with this particular mod on our cars). I'm certain the next time around will be much better. We also found a way to do it a bit faster when working on mine. Multiple days isn't even a possibility. Make sure to let them know that Ryan with the M3 sent you, btw, and have Isaac do the work.

Wow even then 4 hours isn't too shabby! Hopefully I can get this done this weekend. Thanks for the tips!

[Ron1n]

Originally Posted by yongj

Wow even then 4 hours isn't too shabby! Hopefully I can get this done this weekend. Thanks for the tips!

No worries. If you have any other questions, gimme a shout. I also strongly suggest doing the same mod I did, versus the ACM mod. I personally found the ACM mod sound to be far worse.

[yongj]

Originally Posted by Ron1n

No worries. If you have any other questions, gimme a shout. I also strongly suggest doing the same mod I did, versus the ACM mod. I personally found the ACM mod sound to be far worse.

I'm new to the difference. Mind sharing your wisdom?

[Ron1n]

Originally Posted by yongj

I'm new to the difference. Mind sharing your wisdom?

The muffler has inner and outer chambers. The inner chambers have 4 pipes (2 pipes that are pretty much fully perforated, and 2 others that only have a small amount of perforation. This is where the OEM mod comes into play. The 2 pipes that are mostly perforated are cut out and replaced with solid pipes (straight pipes, if you will), welded back in, and you get the sound that I have in my video.

The ACM (AUTOcouture Motoring) mod makes adjustments to the outer chambers. By default, the exhaust comes into the outer chamber, goes through the inner chamber, and comes out the other outer chamber, and then out to the end of the exhaust (this happens on both sides). What you do with the ACM mod is bypass the internal chambers completely, effectively making a straight-pipe. A y-pipe is used from the entry point to the outer chamber to the exit of the chamber (a y-pipe is needed because 2 exhaust pipes).

The sound that comes out as a result of each mod is very, very different.

This video might help you in comparing the actual audio. Far right E92 = stock exhaust, far left E92 = OEM Perf Mod, E93 in the middle - ACM mod

Hopefully this all gives you a better idea, and what direction you might want to head with this. If you're unsure, I'd suggest doing the OEM Perf Mod first, and decided whether you like it or not. If you don't, you can do the ACM mod (which will bypass your OEM Perf mod) and go that route without having to create too much more work.

The visual below may help in understanding how the exhaust is laid out.

[yongj]

Originally Posted by Ron1n

The muffler has inner and outer chambers. The inner chambers have 4 pipes (2 pipes that are pretty much fully perforated, and 2 others that only have a small amount of perforation. This is where the OEM mod comes into play. The 2 pipes that are mostly perforated are cut out and replaced with solid pipes (straight pipes, if you will), welded back in, and you get the sound that I have in my video.

The ACM (AUTOcouture Motoring) mod makes adjustments to the outer chambers. By default, the exhaust comes into the outer chamber, goes through the inner chamber, and comes out the other outer chamber, and then out to the end of the exhaust (this happens on both sides). What you do with the ACM mod is bypass the internal chambers completely, effectively making a straight-pipe. A y-pipe is used from the entry point to the outer chamber to the exit of the chamber (a y-pipe is needed because 2 exhaust pipes).

The sound that comes out as a result of each mod is very, very different.

This video might help you in comparing the actual audio. Far right E92 = stock exhaust, far left E92 = OEM Perf Mod, E93 in the middle - ACM mod

Hopefully this all gives you a better idea, and what direction you might want to head with this. If you're unsure, I'd suggest doing the OEM Perf Mod first, and decided whether you like it or not. If you don't, you can do the ACM mod (which will bypass your OEM Perf mod) and go that route without having to create too much more work.

The visual below may help in understanding how the exhaust is laid out.

Wow thanks so much for all that info! I really appreciate it--no, really, I appreciated your post .

They did the perforated mod for only $375? Might be a silly question but, you didn't have to provide the extra piping or anything did you?

[Bimmer4Kikz]

I was also looking to get this mod done at my local shop, the guy said it would take about 6-8 hrs and around $275-360 which I'm guessing is a fair price?

[djDori_C]

Originally Posted by Ron1n

The muffler has inner and outer chambers. The inner chambers have 4 pipes (2 pipes that are pretty much fully perforated, and 2 others that only have a small amount of perforation. This is where the OEM mod comes into play. The 2 pipes that are mostly perforated are cut out and replaced with solid pipes (straight pipes, if you will), welded back in, and you get the sound that I have in my video.

The ACM (AUTOcouture Motoring) mod makes adjustments to the outer chambers. By default, the exhaust comes into the outer chamber, goes through the inner chamber, and comes out the other outer chamber, and then out to the end of the exhaust (this happens on both sides). What you do with the ACM mod is bypass the internal chambers completely, effectively making a straight-pipe. A y-pipe is used from the entry point to the outer chamber to the exit of the chamber (a y-pipe is needed because 2 exhaust pipes).

The sound that comes out as a result of each mod is very, very different.

.

Very interesting!
I'm wondering with that said, I wonder if going this route can eliminate the chambers completely... I'd assume there would be a lot of weight savings ...

[vsix]

Guys, money well spent on such a mod!

[Ron1n]

Originally Posted by yongj

Wow thanks so much for all that info! I really appreciate it--no, really, I appreciated your post .

They did the perforated mod for only $375? Might be a silly question but, you didn't have to provide the extra piping or anything did you?

I provided...the car. That's it. They removed the muffler on the spot, did all the cuts, welds, etc, with their own tools and materials. The amount of piping needing really isn't much at all.

Originally Posted by Bimmer4Kikz

I was also looking to get this mod done at my local shop, the guy said it would take about 6-8 hrs and around $275-360 which I'm guessing is a fair price?

No offense to your local guy, but it can be done a lot more quickly than that, and still be quality. But the pricing sounds about right, if not a little low, from my experience.

Originally Posted by djDori_C

Very interesting!
I'm wondering with that said, I wonder if going this route can eliminate the chambers completely... I'd assume there would be a lot of weight savings ...

Probably not enough to make a big difference, really. At least not a noticeable one. the ACM mod does effectively eliminate the inner chambers, but still leaves all the tubing in them.

[yongj]

Hey Ryan, just made my appointment for next Wednesday! I spoke with Rick but wasn't sure if he knew how to do this. He asked that I bring pictures or whatever visuals that might help them get the job done. He did remember working on your car but he didn't seem confident in reproducing the work he did on yours to mine.

That being said, was there anything special you did that helped them with this process? I'm planning on bringing the diagram you showed me earlier (stock muffler picture) to help them get a better understanding of the perforated pipes that are going to be replaced.

Thanks!

[Ron1n]

Originally Posted by yongj

Hey Ryan, just made my appointment for next Wednesday! I spoke with Rick but wasn't sure if he knew how to do this. He asked that I bring pictures or whatever visuals that might help them get the job done. He did remember working on your car but he didn't seem confident in reproducing the work he did on yours to mine.

That being said, was there anything special you did that helped them with this process? I'm planning on bringing the diagram you showed me earlier (stock muffler picture) to help them get a better understanding of the perforated pipes that are going to be replaced.

Thanks!

What time's your appointment?

One thing I'd suggest is having them work from the bottom of the muffler, instead of the top (we did it from the top so that the weld work wouldn't show, but it made it harder for Isaac).

If you really need help, I can probably swing up there and walk them through it again, not a big deal.