Equal-length exhaust discussion: new S55 sounds

[M3R1]

Originally Posted by ClearMinded

Yeah, the Eisenmann system looks like "OEM" but louder. And the tips as you said are high quality and I really like the 6 different options what they offer. I never really understood what's the point of those big tips...For me even a stock G80 exhaust tip is already too big.
Do you have any sound clips only with the Eisenmann exhaust? I saw some videos, for me it seems a little bit raspy. To tell you the truth, I haven't heard any big brand M4 exhaust in person.

No clips of anything other than the combo. I installed both the Eisenmann and AA EL mid pipe at the same time. I would imagine that if you heard rasp it was the race version.

[TractionControlDelete]

Sounds added
https://youtu.be/8VTjYQkoMTA?si=GvKLfTQw5XwiLRsh

[RugbyBro]

Originally Posted by TractionControlDelete

Sounds added
https://youtu.be/8VTjYQkoMTA?si=GvKLfTQw5XwiLRsh

Sounds great but probably needs another resonator somewhere in the chain.

FWIW resonated equal length will get you this sound while maintaining cats, so something to consider for CA or emissions limited situations.

[Rokoz]

Originally Posted by TractionControlDelete

Sounds added
https://youtu.be/8VTjYQkoMTA?si=GvKLfTQw5XwiLRsh

It sounds pretty decent - the fact they couldn't make it truly equal with the 2 to 1 is a bummer. It won't sound quiet right if you don't account for the full 14 inch different from side to side

[McIntoshMotorSports]

Originally Posted by Rokoz

It sounds pretty decent - the fact they couldn't make it truly equal with the 2 to 1 is a bummer. It won't sound quiet right if you don't account for the full 14 inch different from side to side

Even with a true equal length downpipe you’d still have the unequal length of the runners pre turbo as others have stated.

[McBobby Jr]

Originally Posted by McIntoshMotorSports

Even with a true equal length downpipe you’d still have the unequal length of the runners pre turbo as others have stated.

That’s the conclusion I think many have come to and I realized this a long time ago. Single turbo is the best way to fix the sound of the S55, regardless of whether it’s a cast or tubular manifold it will sound better than a twin turbo setup.

[Rokoz]

Originally Posted by McIntoshMotorSports

Even with a true equal length downpipe you’d still have the unequal length of the runners pre turbo as others have stated.

Good point - I imagine the greater the distance the more impactful it is. Do we know what the runner length is? I was just looking at some diagrams after you commented

[McBobby Jr]

Originally Posted by Rokoz

Good point - I imagine the greater the distance the more impactful it is. Do we know what the runner length is? I was just looking at some diagrams after you commented

Both manifolds have unequalized runners, on bank 1 cylinder 2 runs short and merges closer towards cylinder 1. On bank 2 cylinder 5 runs short and merges along the middle between cylinder 4 and 6. The manifolds are both unequal and unequal in runner length and to make it worse the downpipes and exhaust are unequal length as well.

[ra2289]

DriftWorks 2-1 downpipe is now up for preorder: Outcast 3” Downpipes

Don’t like the O2 sensor routing (on the one side) but may still have to give this a try.

[BlakeJ]

Originally Posted by M3Dreams

Since your posts and videos really helped put me on the right path, here is what I have to report:

First, what were my objectives (in order of importance):
- Get rid of the Tractor/Mower like sound with valves open.
- Get a little bit more exotic sound than the plain vanilla S55 raspy sound.

Well, objective achieved!

Setup:
Stock DPs - AA Equal Length Mid-section, AA Resonated (Passenger side only) end pipe, Stock ZCP Muffler

I was looking to get rid of the tractor 3-cylinder sound, while not becoming an unbearably loud, rice-rocket, race-car, because IMHO, BMWs are sports cars for the street, not race cars. After switching to AA Equal Length Non-Resonated setup, I was initially very happy that it got rid of the tractor sound, but it introduced the following:

- Ear piercing 3K rpm resonance/boom
- Warm startups (open valves) screamed Rice-Rocket
- Some rattles till car warmed up fully

After following posts and listening to RugbyBro videos, I decided to switch to resonated pipes. However, I only replaced the Passenger side pipe with a resonated one, and all problems solved. Now:

- Very very minor, almost exotic 3K rpm resonance which mellows down even more after warmup.
- Warm startups (open valves) are appropriately aggressive for a sports car, and not a loud blat screaming I am a rice rocket. Your neighbors won't hate you anymore, lol. No need for BootMod to eliminate cold start routine.
- Very minor rattles that disappear within 1 minute of startup. These are mostly coming from the well-known valve baffle areas, and the exhaust warming up.
- The higher pitched exhaust note past 3-4K rpm still exists and is extremely enjoyable when driving through under-passes, or even merging into traffic. I don't have to WOT to enjoy the exotic sounds, they can be enjoyed on the street as well.

All in all, a big thanks to RugbyBro and mike@x-ph.com for helping me achieve my objective. Thank you both! RugbyBro, I highly recommend, if you are good with the wrench, to put the car up on ramps, and swap the driver's side pipe back to non-resonated. I am pretty sure you won't regret it. IMHO, the 1 hour spent is at least worth the try.

Thanks to a few of you, I’ve installed the resonated EL midpipes with factory downpipes and muffler. I’d like to see if you (or anyone reading this) would like to trade EITHER a driver or passenger side NON-RESONATED connector pipe for my RESONATED connector pipe? Takers?

[Valvetronic Designs]

Pretty saucy combo! Is resonated downpipes the way to go?

[mike@x-ph.com]

Originally Posted by Valvetronic Designs

Pretty saucy combo! Is resonated downpipes the way to go?

[delz0r]

Originally Posted by ra2289

DriftWorks 2-1 downpipe is now up for preorder: Outcast 3” Downpipes

Don’t like the O2 sensor routing (on the one side) but may still have to give this a try.

This is super interesting. Adding a single mid and the option of adding a cat to the single mid for emissions compliance is potentially a great compromise.

[ra2289]

Originally Posted by delz0r

This is super interesting. Adding a single mid and the option of adding a cat to the single mid for emissions compliance is potentially a great compromise.

Yeah, it definitely opens up some more options.

[deli333]

Originally Posted by Valvetronic Designs

Pretty saucy combo! Is resonated downpipes the way to go?

I have been telling this for a long time. Resonated downpipes and resonated single mid makes the car sound like v6, super smooth, no embrassing sound at any rpm range.

[Valvetronic Designs]

Is this the ultimate setup? Sounds damn near single turbo!

https://youtu.be/JnVUIAj9SyQ?si=2QcPJ2u81bI9N080

[2sporty]

Originally Posted by Valvetronic Designs

Is this the ultimate setup? Sounds damn near single turbo!

https://youtu.be/JnVUIAj9SyQ?si=2QcPJ2u81bI9N080

That sounds absolutely terrible. Tons of rasp. Single turbo does not sound like that at all.

[Valvetronic Designs]

Originally Posted by 2sporty

That sounds absolutely terrible. Tons of rasp. Single turbo does not sound like that at all.

did you want the full video?

[TractionControlDelete]

Sounds great to me. If anything, the F80 sounds better in-person so I imagine the valvetronic is incredible irl

[greysea]

Originally Posted by TractionControlDelete

Sounds great to me. If anything, the F80 sounds better in-person so I imagine the valvetronic is incredible irl

Didnt that one guy regpaq that went to thunder hill with you have the valvetronic exhaust? I watched his youtube of installing it. Think I saw his name in your thunder hill thread.

I cant remember though if he had the titanium version…

Videos never do true justice for sound.

[TractionControlDelete]

Originally Posted by greysea

Didnt that one guy regpaq that went to thunder hill with you have the valvetronic exhaust? I watched his youtube of installing it. Think I saw his name in your thunder hill thread.

I cant remember though if he had the titanium version…

Videos never do true justice for sound.

Come to think of it, I do remember he had some version of the valvetronic. It did sound good whatever setup it was. The one from this YouTube video sounds different than anything else I’ve heard on the platform but I guess audio equipment has an effect. The regpaq exhaust didn’t sound like this video, to me atleast. It sounded like the middle ground between the Single and Equal Length Midpipe when paired with the stock muffler.

[WarMachineM3]

I personally think there is good rasp and bad rasp. The Valvetronics titanium system produces and lot of good rasp. Adding any resonators cleans it up a little, but becomes less raspy. It's sounds more like an NA inline six as opposed to single turbo. I would say the V2 Valvetronics titanium equal length system, however, it's close to sounding like a B58, but not as smooth, but still sounds great. You have to hear it in person to really get the right judgement on it, as with any exhaust.