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Discussion Starter · #1 · (Edited)
I've built a few S54 tourings now and with more on the schedule I have been going over muffler choices. There are quite a few solutions out there but no real data on how well they work as far as power, sound and weight are concerned.

The way most of these cars are put together are by using the OE design section 1. Then from there they either use a stock section 2 (S2) with a muffler (Stromung) or the S2 is cut down and a muffler is fitted and welded on. The last mainstream option is from Super Sprint and they have a complete replacement for the S2 and muffler.

The planets have aligned and I happen to have a bunch of muffler options available at the moment.

***When looking at the scale display if there is only one scale pictured in use it will be the LF, if there are two it will be the LF & RF, disregard the readings from the the scales not in use, for some reason the display shows something while the scale is not connected.

1. Stromung - Stromung's muffler is claimed to be a 100% bolt on option with no modification to the car and uses the unmodified S54 S2. It is offered as the easiest option as it is a straight bolt on with no modifications. *My muffler did not attach to the S2 properly and caused a leak (I think this was just a tolerance in manufacturing), I was able to make it seal but it did take a bit of work. Muffler and S2 weight 44#.




*For my preference this muffler is a bit to loud and has a noticeable drone that I am not fond of. When I talked to Scott at Stromung he told me there is no good way around this because the size of the muffler when used with the S2 is just smaller than ideal. And if we wanted it quieter then we would have to modify the S2 because the only reasonable way to lower the volume would be to use a larger muffler, enter all of the below.

2. SuperSprint - The kit from SS is a full replacement of the S2 and S3 and bolts into the factory location of the sedan/touring. This is the next true bolt on solution, but is costly as can be expected with a SuperSprint product. SS has increased the muffler size and thus made the corresponding pieces so no fabrication is required. The kit is (3) sections and a couple of the sections have multiple options. This setup weights a total of 47#








The following all will use a modified S2 with the muffler welded onto it. For these we take a stock S2 and fit the corresponding muffler to it in a convenient location. The BMW S2 has "D" shaped pipes that measure round 60mm in diameter. Most of these mufflers have round pipes that are closer to 50mm. Because of this "necking" down there is concern that power is being left on the table. These are ideal for the decreased sound level, affordable options to source and (save for the E36) are light. Note most of these mufflers when installed as a replacement join at the exact same spot on the exhaust, because of this I am going to only swap the muffler and not the entire S2 section for these, which should also help cut down on variables.

3. Dinan - Dinan replacement muffler off of a 330i (Note: Dinan shows the part numbers the same for 325/330).
https://www.dinancars.com/product/d...r-bmw-325i-e46-2001-2006-2/?series=&mid=330i/

4. BMW Performance - The BMW Performance muffler was offered from BMW over the counter and is from a 325iT, RealOEM shows the part numbers are the same whether it is for a 2.5L or 3L. The muffler and S2 weight 42#




5. E46 ZHP muffler.

6. US E36 M3 muffler. I ended up cutting this one a bit short and as such had to bridge a fairly large gap when fitting up, so excuse the poor welding on this one. Note: I have not added the hangers and it is missing the bracket at the front so it will get another couple of pounds added to it. I'll update this post at that time, but this is the starting point to look at. Muffler and S2 weight 65# right now.




So, I have a bunch of mufflers and access to a chassis dyno. I'm going to swap these mufflers back to back on the dyno and see what happens. The car is a E46 Touring with a complete S54 conversion (minus bodywork). It is a "stock" engine with a Dinan CAI, Euro headers, Euro cats and is running Euro software. What would YOU like to see in this test? I figure we will make (3) runs with each setup. Might even pick one setup and test it catless and I have an oversized S2 that I might add to the Stromung for fun. Then I plan to set up a microphone maybe inside the car and on a tripod out side the car to measure sound levels. Lastly I'll weight the complete S2/Muffler combos for comparison.

I'm still putting all the details together, but wanted to start this thread in case someone comes up with something I hadn't thought of and want to implement it as part of this test.
 

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I just uploaded a video to YouTube of my exhaust note when my car was in n/a form. The modifications that helped produce this sound consisted of:

- FluidMotorUnion velocity stacks
- swaintech coated Megan headers
- CSL cams
- Alpha N tune
- custom 2.5” exhaust (y pipe from headers to single exit using one resonator and a Speed Factory Racing muffler)


https://youtu.be/jGqG-DNlvh8


Sent from my iPhone using Tapatalk
 

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In for the results. From my reading elsewhere I thought that the Stromung option was made specifically for the s54 swap, so the pipe diameter discrepancy is a bit disappointing.

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Discussion Starter · #9 ·

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Discussion Starter · #11 ·
Awesome!

George, group: is there an offering from Corsa, Borla, MagnaFlow, etc. that will work for this application?
I'm not aware of a bolt on conversion muffler so any of these options would have to be spliced onto the S2 like your ZHP muffler. If there was an option I would be certainly interested to try it.
 

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Very interested in this one. Sounds like a great thread and a great excuse to put it all together in a video.

I'm assuming all of these will be done on the same car and same day so that the dyno results will remain meaningful?
 

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In for the results. From my reading elsewhere I thought that the Stromung option was made specifically for the s54 swap, so the pipe diameter discrepancy is a bit disappointing.
I think George got a muffler that shouldn’t have made it past Stromung QC. Mine has bolted up perfectly with no leaks and has 60mm OD inlets that match the OE M3 section 2 diameter.

It is too loud around town, on the Highway it blends in with road noise. I added a pair of auger inserts to tone it down until I decide to chop/cut/weld a permanent fix.
 

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Mark, I'm scheduling dyno time for next week so if you come up with something before then we'll add it to the list.

George, on second thought, I’m going to wait until you have data on how the ZHP muffler stacks up against the others in the test group.

I can’t wait to see how this all plays out... thanks for doing this, mang.


Please excuse brevity and / or grammatical errors - iPhone
 

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Exciting!

If the US spec e36 m3 muffler option could keep the e46 M3 section 2 resonator (as in, have the e36 M3 muffler weld in after that), that would be most interesting to me!

I believe that eliminates the portion of the e36 muffler that's a smaller diameter.
Smaller up front by the flange, so best to cut off that portion before welding:

http://www.uucmotorwerks.com/rsc36/RSC36_BIMMERFEST_files/uuchp05.jpg

Hopefully this thread doesn't result in my buying yet another supersprint product! :rolleyes:
 
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