S54 Swap Muffler Suggestions

[cwlo]

The borla, magnaflow, and most aftermarket generic mufflers tend to be loud. Dynomax super turbo is a bit quieter.

[dude8383]

Looking forward to seeing how things work out for you!! Would love to keep the setup but I think my best bet is configuring an E36 catback to work because they're the only ones out there with large enough mufflers that actually soak up noise!

[R3VM3UP]

Ah, I did run across your videos on youtube and I think your car actually sounds pretty awesome, bummer that it's too loud. Maybe you can figure out a way to keep the same sound but just tone it down a tad. I wonder if the 3" section is a big contributor.

I've been practicing stacking dimes with the TIG and my H pipe is in progress. I'm waiting on a couple more parts but I hope to have this thing fabbed within the next month or so and I'll report back on the progress.

[dude8383]

I have a few vids but none of them really highlight how loud it is to be honest.

https://www.youtube.com/watch?v=lMPa6AnPB48

https://www.youtube.com/watch?v=HtirE9tgRj4

Here's what the system looked like the first time around with the two smaller magnaflow mufflers:







Very interested to see how it turns out for you man! Please check back in once you get around to changing things around :)

[R3VM3UP]

Interesting that the volume is still an issue even with a setup with so many mufflers. Do you have any videos of it?

I ended up just ordering the Borla 400286, which is 19" X 4" X 9.5". So overall it will be pretty similar to your setup, minus the cats. The Borla muffler is a little bigger than the Vibrant 1047, so I sure hope that it helps. I guess I expect that mine will be pretty loud no matter what, but I really hope it's not too raspy.

[dude8383]

I'm in the same boat as you... except I built a 2.25" all the way to the subframe merged to a 3" single. The drone and overall volume has really made the car not pleasant to drive on long trips.

I have 2 cats, 2x 18" magnaflow mufflers going to a vibrant 1047. Looking at just BMW exhaust systems overall I notice that they do most of their silencing in the rear muffler. Big multi-pipe muffler boxes that really dampen the noise levels. Personally I'm leaning towards having Stromung build me a custom muffler with as much material packed into it as possible because it seems that the E36 guys that do S54 swaps rock the stromung or supersprint stuff and they sound relatively tame inside (from the few vids out there). I'm also going to get rid of the 3" Y and swap out for an X pipe to a dual all the way. Hopefully that shuts this thing up lol.

[R3VM3UP]

Hey all, I'm finally at the point where I'm ready to fab the back half of my exhaust for my S54 swap. Here's what I have so far:

-Megan racing headers
-E46 M3 section 1, chopped off at the resonators and stepped up to 2.5
-Two Stainless Bros round mufflers http://www.stainlessbros.com/25-SS30...ish_p_403.html

What comes next:
-2.5" H pipe
-Dual 2.5: back to a muffler in the stock location

I'm looking for input/suggestions on a muffler for the last section.

Current candidates are:
Borla Pro XS

https://www.summitracing.com/parts/bor-400286?rrec=true

Flowmaster Super 44

https://www.summitracing.com/parts/flo-8425454

I'm actually looking for whatever is the more quiet option. The Borla is obviously a larger muffler, but it's a flow through glass pack design, whereas the Flowmaster is a chambered muffler, so I'm wondering if it's possible that the Flowmaster would be quieter. The two Stainless Bros "mufflers" that are on there now are really just more or less glass pack resonators, similar to the one on the stock E46 M3 exhaust. I think they will help quite a bit with the rasp, but they are still really loud right now. I really don't like rasp and TBH I don't think the S54 exhaust really ever sounds that great no matter what you do to it, so I'd rather hear the induction noise.

My requirements for the muffler are:
-Must be dual 2.5" in/out
-The quieter the better, I want zero rasp if possible
-stainless (304 preferably, but I'd do 400 series. The other requirements are more important)


Also to address a couple other things that will probably be asked:
-why not 3"? Ground clearance mostly. I know .5" isn't that much but it's already very low around the rear subframe, so I'll take any little bit that I can get. Noise also played a smaller role in the choice, since I don't want a lot of drone.
-why dual 2.5"? Yes, I know it's overkill for a stock S54 and 2.25 would be adequate. I opted for 2.5" simply because there are a lot more muffler/resonator options at that size. Plus, if I ever do cams/airbox on the S54 there will actually be some gains from the 2.5" vs. a 2.25".


So that's it folks, any suggestions on other muffler options I should consider? There seem to be lots of options very similar to the Borla, but I guess my ideal muffler would be something in 304 stainless that is about the size of the Borla, but chambered rather than glass pack. Does such a thing exist?