Exhaust options

[xt]

Hi. New to the party. Time to upgrade my stock exhaust for my 128i M sport. I'm looking for an axle back option. I know this topic is beaten to death

Any good recommendations besides the three below that will fit somewhat easy?

I hear a 135i N55 exhaust might be a good idea, of the Performance option? Big price difference and tip size. Not wanting to change the dynamics w/ deletes,straight pipe or catback. Just a simple sound mod. I'll do an intake later. So far I'm looking at the SuperSprint, GTHaus Meisterschaft GT, or Eisanman race, but will continue looking.

[Ryan1963]

Have you considered removing the resonator while keeping the stock muffler? If you remove both resonator and muffler, the sound is quite a bit louder, had both removed on my car and it’s almost too loud tbh. Swapping for aftermarket muffler may be unnecessary expense for your endeavor.

[4JawChuck]

I can say that removal of the original exhaust manifold with cats and replacement of the secondary cats with a straight front pipe with headers gives a really nice “no drone” sound which is louder than stock but not offensive.

Headers + no cats+ stock exhaust with mufflers/resonator is a winning combination for a good sporty sound that does not offend.

After these mods it really feels like the car was originally designed to sound like this but emissions requirements muffled the intent.

Has burbles on the over-run and everything, pretty impressed I didn’t have to change the exhaust much to get the sound I wanted, wouldn’t change anything with how this works out.

[WrathOTM]

Originally Posted by 4JawChuck

I can say that removal of the original exhaust manifold with cats and replacement of the secondary cats with a straight front pipe with headers gives a really nice “no drone” sound which is louder than stock but not offensive.

Headers + no cats+ stock exhaust with mufflers/resonator is a winning combination for a good sporty sound that does not offend.

After these mods it really feels like the car was originally designed to sound like this but emissions requirements muffled the intent.

Has burbles on the over-run and everything, pretty impressed I didn’t have to change the exhaust much to get the sound I wanted, wouldn’t change anything with how this works out.

Post a video of your setup, I'm sure more than a few of us are interested in a similar setup.

[4JawChuck]

My son is an audio engineer and out on a job doing film work.

He has multi channel digital recorder and labs so I can get quality audio inside and outside the car.

I will wait till he gets home to get accurate sound for others to hear.

[jdt10768]

Originally Posted by 4JawChuck

I can say that removal of the original exhaust manifold with cats and replacement of the secondary cats with a straight front pipe with headers gives a really nice “no drone” sound which is louder than stock but not offensive.

Headers + no cats+ stock exhaust with mufflers/resonator is a winning combination for a good sporty sound that does not offend.

After these mods it really feels like the car was originally designed to sound like this but emissions requirements muffled the intent.

Has burbles on the over-run and everything, pretty impressed I didn’t have to change the exhaust much to get the sound I wanted, wouldn’t change anything with how this works out.

Did you just take to a muffler shop and have this done? Cost? Pics?
Looking forward to video! Thanks

[4JawChuck]

Nope, Autowerke headers with a cat less primary pipe was all that was replaced, original was severely corroded at the bolted flange which was a concern which is why I didn’t just cut the secondary cats out and have a piece welded in…which is easily done for cheap.

[Bougnoul34]

He is in California like me, if we make changes we have to reverse them for Smog inspection every 2 years.

[AmuroRay]

I had Active Autowerks headers, to the Super Sprint Secondaries and BMW performance Exhaust mid section.

It was LOUD, not even in a good or cool way. Just loud. Then again, I was going for Maximum performance, and there was still power and less noise left on the table.

If it were me, go with a universal 3" in muffler and weld that up to your exhaust system. If you want more power - add headers. If you want to eek out the last bit, you could change the midpipe and Y merge.

[2tonik]

I love my 128i with DISA intake, AA headers, and MILV's - but it was too loud after the headers were added. I'm a broadcast sound mixer and have to protect my hearing. The shop that installed the headers said the car would be "slightly louder than stock". In reality it was twice as loud. I think a lot of mechanics and gear heads have hearing loss, BTW..... So they don't have an accurate concept of how much louder a mod will because it doesn't seem loud to them.

Interior noise levels were in the 80+ dB range (windows up - open windows even louder) after the headers were installed. Way too loud for me. I had to have a 1/4 wave Helmholtz resonator fabricated to reduce low frequency drone at 125Hz plus 2 Car Chemistry 2 1/4" baffles mounted just after the headers to reduce overall sound levels.

Cost me about 10hp10Tq but my ears are much happier. The car's exhaust still sounds glorious with windows up or down, but volume is livable to me and less intrusive to others - about 73dB at its loudest. The photogs still hear me coming when I'm a few corners away at Tail of the Dragon...

Corrected dyno results are 288HP and 273TQ with DISA, AA header, MILV's, and the CC inserts. (The 1/4 wave Helmholtz pipe doesn't have any effect on power).

Sound Samples:

https://www.dropbox.com/scl/fi/m5phf...serts-001.WAV?
rlkey=5vgasn7vx1aip3mc9dn2j99za&dl=0

https://www.dropbox.com/scl/fi/2xaj7...sxw5nl3pe&dl=0

[ZHPizza]

I don't know if OP is still looking for options, but I test drove a 128i with a muffler delete and found it to be surprisingly docile. I hate a loud exhaust and the idea of a muffler delete is the worst (coming from the e46 platform), but I genuinely thought it sounded perfect. Like a factory M car volume, if that. No drone/rasp that I noticed.

So OP, if you're looking to improve the tone and don't plan to go headers or cat delete in the future, replacing the muffler with straight pipes could be the best of all worlds (sound, weight, and cost).