[n8dgr84]

AFAIK the difference between Sport and S+ is that S+ has more aggressive throttle response map (shorter pedal) and some anti-lag features built-in to decel and shifting.

You won't know until you try it, but, I think adding the resonators will reduce the "barkiness" and add some warmth and mellowness to the tone. Make it sound more like a 2JZ. It will also slightly reduce the drone and improve in-cabin comfort.

[No_curebimmer]

Originally Posted by n8dgr84

AFAIK the difference between Sport and S+ is that S+ has more aggressive throttle response map (shorter pedal) and some anti-lag features built-in to decel and shifting.

You won't know until you try it, but, I think adding the resonators will reduce the "barkiness" and add some warmth and mellowness to the tone. Make it sound more like a 2JZ. It will also slightly reduce the drone and improve in-cabin comfort.

I’m tracking with you, but my recent tweaks of the BimmerLink and MHD burble management seemed to reduce the in cabin droning. And clearly, all that can be amplified/diminish via engine drive mode (ie zero such issues when in efficient). For the life of me, I couldn’t capture downshifting farts while in S+ (which I presume are primarily affected by boost pressure, RPM and rev match feature).

My biggest find was that, in MDM mode, the engine/exhaust behave differently than simply S+. For example, I noticed that the revs hang for much longer when downshifting, and as a result (my speculation) affect the exhaust notes differently. In S+, the revs are quicker to come down, forcing rev matching and thus downshifting farts. I wonder…would turning off rev matching minimize what I call ‘downshifting farting’?

Now, let’s break this down scientifically:

1. mufflers quiet (i.e. better manage air flow) exhaust volume across all RPMs

2. resonators prevent unwanted resonance (what we call general raspiness and/or in cabin droning) which happens within a particular RPM range.

3. There are many kind of resonators (diameter and length size, chamber design, materials used, etc) - but these ones are made by AA to specifically address raspiness and some in cabin droning for M2C vehicles (as confirmed by them to me via email during the purchase process).

Empirical data aside from users on this forum, I am not entirely convinced that, as a result of introducing these particular resonators, my dB volume will noticeably lower nor ‘diminish’ the strong muscular exhaust notes I currently have.

I will keep my appointment this week to install them, so stand by for some impressions and other ‘non pro’ vids.

[FMOS Racing]

I'm looking forward to your results.

I've added resonators to several vehicles in the past, both "single pipe" style and "merge" style to add some smoothness to the exhaust note. There's a particular tone that appeals to me, and a high quality resonator and muffler combo has almost always gotten it for me, though sometimes the size of the resonator/muffler is an experiment.

I currently have the AA unresonated EL mid, along with their valved axle back. I'd love to soften some of the unnecessary exhaust blats. I simply don't have that much need for attention.

[No_curebimmer]

At the performance muffler shop!

So I’ll hit 2 birds w/ one stone:

1. Remove the clamps - you can see from the condensation build up that I have exhaust leaks there
2. The resonators will be installed and WELDED in place where I encircled in red

[No_curebimmer]

Done!!!

Attached are pictures of the installation

[No_curebimmer]

Also took a short clip:
https://youtube.com/shorts/pCCjyBAsd9Q?feature=share

Brief initial observiert:

Pros:
- exhaust flow is definitely more controlled
- on my way from the shop, I haven’t experienced in cabin droning
- also, no raspberry sounds upon downshifting

Cons:
- it is somewhat quieter and less roudy than before

I can see that I could take my M2C on a cross country trip, and drive it in S+ w/o droning or headaches.

Bottom line: it’s a balancing act with the exhaust on these S55.

W/O Resonators:
Adding AA EL and Dinan muffler definitely changed/improved the exhaust notes for the better (deeper growl, lower frequency). However, occasional raspiness was still present as journeyed in this thread .

WITH Resonators:
Car is now, shall I say, ‘more grown up’? I have not noticed any raspiness at any RPM levels or driving styles/modes.
Downside though: quieter exhaust experience.

[FMOS Racing]

You should get them to sponsor you. Exactly what I would hope to get from the resonators. Thanks!

[No_curebimmer]

Let’s give credit where it is due:

ONLYACTIVE - your Equal Length midpipe (and now, resonators) are Top Shelf, completely transforms the unbecoming stock S55 exhaust sounds! Your R&D and manufacturering prowess has given countless smiles to us S55 owners!

Dinan_Engineering Your exhaust/muffler for M2C platform is equally superb: lightweight, exquisite design and fabrication create a fantastic exhaust note, by itself or even when paired with something like AA EL, it is, in my humble opinion - the best icing on a very special cake!

Special shout-out to my pro installer: Kinney Muffler Shop in Ft Worth TX. They REALLY listen to their customers, and will tirelessly work with you to achieve what you want out of your exhaust - if you’re anywhere near N Texas…I highly highly recommend Kinneys for your custom exhaust work - they will exceed your expectations!

https://kinneysmufflershop.com/kinne....com/HOME.html


Thank you all - 5 stars indeed! I’m a happy happy camper now 😃

[n8dgr84]

Definitely sounds deeper with the Dinan but more refined and tamed now.
Now you can enjoy road trips with no droning!
Very nice!

[e90m3808]

If the resonators are the key to eliminating the 2k rasp- it will be hard to decide if I can tolerate the quieter sound.

[No_curebimmer]

Originally Posted by e90m3808

If the resonators are the key to eliminating the 2k rasp- it will be hard to decide if I can tolerate the quieter sound.

So I can see how this could be a dilemma for most of us upgrading the S55 exhaust: we want best of all worlds don’t we?

However, I want to make a clear distinction between noise vs sound! Prior to the resonators, it’s true, my car had more noise, it was indeed more roudy so to speak (uncontrollably in some ways). After the AA resonators installation however, the result turned out to be a focused and purposeful Super OEM++ exhaust system.

By controlling the ‘noise’, one would end up having an enjoyable ‘sound’ experience.

While I would have loved to retain some fractions of that ‘roudy noise’, it was all worth it to eradicate headache inducing noise (droning) and end up with a car that now, in my opinion, sounds like a high-end Euro performance car should!

BMW = Freude am Fahren, noch einmal, ja?

[maxcbrdriver]

It's interesting seeing the impact the resonators have in your setup. I'm running the AA single with resonators and a Remus Race and while I have no idea what it would sound like without them, I can tell you that's it's plenty rowdy and loud with valves open. Valves closed is substantially quieter, which is interesting in its own right bc the Remus Race uses helmholtz resonators instead of a typical baffle design. Amazing how effective they are.

[No_curebimmer]

Originally Posted by maxcbrdriver

It's interesting seeing the impact the resonators have in your setup. I'm running the AA single with resonators and a Remus Race and while I have no idea what it would sound like without them, I can tell you that's it's plenty rowdy and loud with valves open. Valves closed is substantially quieter, which is interesting in its own right bc the Remus Race uses helmholtz resonators instead of a typical baffle design. Amazing how effective they are.

I’ll admit, I originally wanted a Remus Sport but the extremely long wait time they had mid 2020 turned me looking for more attainable options. So as it happened, I got my Dinan within a few weeks of my order…given the supply-chain madness a few years back, I considered myself lucky (like most, I hated my OEM back box with passion).

But yeah, Remus Race is arguably the most raucous option out there for M2C, especially when paired w/ AA single midpipe, which IIRC, is noticeably louder than EL. Your setup is quite free-flowing, so do you have raspiness?

So I’m sorta curious…when comparing the before/after vids, what do you guys notice?

[n8dgr84]

IMO if you had big wang and CF aero everywhere and only drove occasionally, your non-resonated exhaust would be more suitable.

The sound you have now seems to better suit the build and intended function of a daily driven M2.

I like it.

[No_curebimmer]

Originally Posted by n8dgr84

IMO if you had big wang and CF aero everywhere and only drove occasionally, your non-resonated exhaust would be more suitable.

The sound you have now seems to better suit the build and intended function of a daily driven M2.

I like it.

Thanks for comment above ! Not that I’m looking for y’all to validate my AA resonators purchase/install, but it nice to see it my exhaust build ‘resonates’ with some owners (haha!!!)

I documented this AA resonators build to objectively (?) outline the pros/cons of only adding resonators in an EL setup, with all other components being same. With resonators, it is very much still mean, very controlled with plenty of growl, zero raspiness, a purposeful exhaust that sounds the part - just slightly less raw than w/o them…100x better than stock S55!

It’s always a compromise in any mods we do, so at some point we need to put down the sword and enjoy what we have.

PS it is possible that the occasional raspiness I had was due to the exhaust leak I had at the clamps?

[n8dgr84]

Unlikely due to the exhaust leak - those mostly sounds like *flutttutututt*



Btw here's mine for comparison:

https://youtu.be/0B1kNtYKwmo

https://youtu.be/S6Cm9d4FfvQ

[No_curebimmer]

Originally Posted by n8dgr84

Unlikely due to the exhaust leak - those mostly sounds like *flutttutututt*



Btw here's mine for comparison:

https://youtu.be/0B1kNtYKwmo

https://youtu.be/S6Cm9d4FfvQ

Yep, yours has a very distinctive sound, higher pitch I reckon, more ‘racy’ I would say than mine.

[No_curebimmer]

Originally Posted by alan435

I always get so stoked when I see/hear someone with a proper sounding S55, glad you're enjoying the "matured" set up brother!

Vielen Dank mein Freund!

[FMOS Racing]

I ordered resonators for mine yesterday.

Thanks for this thread!

[speedsnice]

I have 2 sets of Active Autowerke resonators for sale. One set is the first Gen and the second set is the larger second Gen resonators.
Available in New York if anyone is interested.

[No_curebimmer]

Uploaded a new vid, thanks to my 11 yr old ;-)

https://youtu.be/JpeA38vmTTo

Whatcha y’all think… fantastisch, ja?

Personally, I find it super super clean: no raspiness of any kind, does not sound like a turbocharged motor at all, and a far far cry from the awful stock S55 tinny/metallic sound.

Only quibble? A small part of me wishes it were 20% louder though…

[FMOS Racing]

Was the 11 year old revving or filming??

I have one of those, too. I think she'd launch a piston out of pure glee if I allowed her to rev the car!

Love the sound. I own several gnarly, cammed, rumbling V8s, so it's not a matter of loudness. I just don't care for the "tinniness" of my M2C's exhaust the way it is right now. I look forward to getting resonators on it.