[No_curebimmer]

Question:
I would like to ask for thoughts on the overall exhaust tone/note/dB changes when adding some resonators to a non-res AA EL + some aftermarket exhaust (MPE, AA, Remus, Dinan etc).

Baseline:
I love the current exhaust note in my ‘19 M2C: deep, throaty w/o raspiness or typical S55 metallic sounds. Don’t want to alter it except to remove the 2 issues I’ve outlined below.

Current specs:
Stock DPs
AA EL, non-resonated
Dinan axelback (modified w/o the x-pipe)
MHD modified burbles (~1 ms in duration + avg aggression)

Problem statement:
In S or S+ only (in efficient, no issues of any kind), besides pretty obvious cabin drone ~ 2,5 to 3k that most aftermarket exhausts experience, my biggest gripe about this setup is that my car ‘blows a raspberry’ upon downshifting (I’m 6 speed, but likely would be same if I had DCT).

I am considering either:
- adding AA’s own resonators and have my shop weld them in place (link https://store.activeautowerke.com/pr...0697273811055)
- or have my very trusted and highly regarded muffler shop source and tig-weld their own version of resonators (more cost effective)

Would adding resonators to my non res AA EL significantly ‘mute’ or ‘muffle’ the overall tone and dB levels but also help with the raspberry farts? Except the 2 issues above, I really love my exhaust, so I wouldn’t want to fix one problem but introduce another instead.

I recall that most of aftermarket exhausts introduce some droning, but is raspberry blowing also inherent?

PS here is an outside clip of my setup…most would agree that it doesn’t sound turbocharged nor S55 typical and an improvement. https://youtu.be/clf886EQ5tk

[inTgr8r]

Do you still get the issue with burbles turned off?

[No_curebimmer]

Originally Posted by inTgr8r

Do you still get the issue with burbles turned off?

Yes - I suppose the ‘raspberry farts’ upon downshifting are more pronounced because of lack of burbles.

[drp087]

I can't say with direct experience with the non-res, but with my Resonated EL + Remus Race, downshift noises are spot on.
In Comfort mode and less aggressive downshifts sounds are nonexistent
In Comfort/aggressive it is subtle yet noticeable
In Sport/aggressive you are in full daily race car mode

There is a little drone but livable.

I went with Resonated to avoid unwanted noises like you mentioned, if anything maybe try HF Cats with the Resonated EL?

[pawelczyk7]

Originally Posted by No_curebimmer

Question:
I would like to ask for thoughts on the overall exhaust tone/note/dB changes when adding some resonators to a non-res AA EL + some aftermarket exhaust (MPE, AA, Remus, Dinan etc).

Baseline:
I love the current exhaust note in my ‘19 M2C: deep, throaty w/o raspiness or typical S55 metallic sounds. Don’t want to alter it except to remove the 2 issues I’ve outlined below.

Current specs:
Stock DPs
AA EL, non-resonated
Dinan axelback (modified w/o the x-pipe)
MHD modified burbles (~1 ms in duration + avg aggression)

Problem statement:
In S or S+ only (in efficient, no issues of any kind), besides pretty obvious cabin drone ~ 2,5 to 3k that most aftermarket exhausts experience, my biggest gripe about this setup is that my car ‘blows a raspberry’ upon downshifting (I’m 6 speed, but likely would be same if I had DCT).

I am considering either:
- adding AA’s own resonators and have my shop weld them in place (link https://store.activeautowerke.com/pr...0697273811055)
- or have my very trusted and highly regarded muffler shop source and tig-weld their own version of resonators (more cost effective)

Would adding resonators to my non res AA EL significantly ‘mute’ or ‘muffle’ the overall tone and dB levels but also help with the raspberry farts? Except the 2 issues above, I really love my exhaust, so I wouldn’t want to fix one problem but introduce another instead.

I recall that most of aftermarket exhausts introduce some droning, but is raspberry blowing also inherent?

PS here is an outside clip of my setup…most would agree that it doesn’t sound turbocharged nor S55 typical and an improvement. https://youtu.be/clf886EQ5tk

I have a similar set up Non res EL and MPE with stock downpipes.. and while yes it is some drone in the lower RPM with sport / sport plus. i don't have the "raspberry " sounds while downshifting ( also 6 speed) but i turned off burbles completely and love the pure exhaust sound,,

[No_curebimmer]

Thanks folks for the input!

So, trying to systematically think this through:

1. An aftermarket exhaust allows for freeer flowing air; the upsides are obvious to most. The downside is that, because the system now has more air flow/volume, there is an added chance of that extra air bouncing off pipiping resonating/vibrating at an unpleasant frequency (ie droning).
2. Resonators are nothing but devices that divert & retard the exhaust pulses in a preset sequence …

Now, at a high level, the secret sauce of a resonator design is the housing of the resonator (length/diameter), and how many diverging paths are implemented. I am not sure if there are resonators that affect only certain (unwanted) frequencies…but that would mean to identify which frequency causes droning.

With that noted… chances are that my existing tone won’t be dramatically changed, likely it will lower the frequency somewhat and help minimize downshifting raspberry sounds + droning.

So…I’ll be getting these from AA and have my shop tig weld them in place

https://store.activeautowerke.com/pr...40697273811055

[No_curebimmer]

FYI - the Dinan has 70mm piping (vs 60mm OEM),so I’m going to have everything welded… attached is my Dinan axelback + non res AA EL welded in place, plus new resonator version (initially they were shorter and slimmer).

I’ve marked up where I believe the resonators will go in.

[drp087]

Sounds about right, I'd also go with the AA resonators, just helps to minimize variables.

Good luck on the chase!

Originally Posted by No_curebimmer

Thanks folks for the input!

So, trying to systematically think this through:

1. An aftermarket exhaust allows for freeer flowing air; the upsides are obvious to most. The downside is that, because the system now has more air flow/volume, there is an added chance of that extra air bouncing off pipiping resonating/vibrating at an unpleasant frequency (ie droning).
2. Resonators are nothing but devices that divert & retard the exhaust pulses in a preset sequence …

Now, at a high level, the secret sauce of a resonator design is the housing of the resonator (length/diameter), and how many diverging paths are implemented. I am not sure if there are resonators that affect only certain (unwanted) frequencies…but that would mean to identify which frequency causes droning.

With that noted… chances are that my existing tone won’t be dramatically changed, likely it will lower the frequency somewhat and help minimize downshifting raspberry sounds + droning.

So…I’ll be getting these from AA and have my shop tig weld them in place

https://store.activeautowerke.com/pr...40697273811055

[No_curebimmer]

Originally Posted by drp087

Sounds about right, I'd also go with the AA resonators, just helps to minimize variables.

Good luck on the chase!

Thanks mate! I’ll post up install pictures and video after the new surgery…

Getting gigly again, ain’t modding fun?

[ESB]

Do you have a video of the downshifts? (I didn’t watch all of the video you included - does the issue happen somewhere there?)

I’m still running just the EL non-res. Stock DPs and muffler. I have burbles turned off via BimmerLink. My downshifts don’t produce any notable sounds. If anything it’s the main part that I feel is lacking in my setup. The downshifts are boring.

[No_curebimmer]

Originally Posted by ESB

Do you have a video of the downshifts? (I didn’t watch all of the video you included - does the issue happen somewhere there?)

I’m still running just the EL non-res. Stock DPs and muffler. I have burbles turned off via BimmerLink. My downshifts don’t produce any notable sounds. If anything it’s the main part that I feel is lacking in my setup. The downshifts are boring.

I don’t have a video of my downshifts…I will try to capture an in cabin drive before I add the AA’s resonators…will post it here.

However…you can actually hear the raspberry sound, as I described it, right around 4s mark in the video I attached in my original post (it’s extremely short, perhaps 1ms in duration max). However, upon some downshifting events (not all downshifts exhibit this issue) - the same sound is extended to > 1s to 1.5s which is way more noticeable.

I will say this re: burbles, given my experience:
- turning off the burbles via Bimmerlink resulted in an overall muted engine/downshifting experience and the engine just ‘felt lazy’ . There aren’t any ‘braaap’ noises, while the rpm’s rise up slower than below…but sure, the exaggerated burbles were gone (PS modding my exhaust increased burbles by min 40%).

- managing the burbles via MHD Tune (I lucked out, my build was June ‘19, so didn’t need DME unlocking): best I can describe it is as low-profile Ferrari downshifting experience: immediate engine response with an accompanying ‘braaap’ exhaust note as the rpm’s suddenly climb up (except ~ 20-25% when it blows a raspberry). Attached is a screenshot of my burbles configuration via MHD…plus I’m running a mild CS tune @ 460 bhp ( OEM+).

[ESB]

Yeah I’m a January 2020 build date so bench unlock is my only option for tuning afaik.

Not going to bother with that in the foreseeable future so removing burbles can only be done via BimmerLink for me. I’d love to tune them like you where they exist but are much shorter … and ideally a bit more random and less predictable. But alas…

I remember your post now about feeling decreased power with that. I don’t think I ever noticed. At this point though I’ve been running without burbles for almost 2 years so even if I did lose some power … ignorance is bliss I suppose.

Fwiw i do still get braaaps on throttle lifts. And sometimes more of a woof (my favorite, but more rare)

[No_curebimmer]

Originally Posted by ESB

Yeah I’m a January 2020 build date so bench unlock is my only option for tuning afaik.

Not going to bother with that in the foreseeable future so removing burbles can only be done via BimmerLink for me

I remember your post now about feeling decreased power with that. I don’t think I ever noticed. At this point though I’ve been running without burbles for almost 2 years so even if I did lose some power … ignorance is bliss I suppose.

Fwiw i do still get braaaps on throttle lifts. And sometimes more of a woof (my favorite, but more rare)

10-4 - sometimes the juice ain’t worth the squeeze!

Like I mentioned above, I will post up an in cabin video while driving spirited and hopefully it will give you a decent baseline (will need to use my iPhone 12 Pro as I don’t have any other gear).

I would suggest you run this test though: turn back the burbles via BLink and see if the motor is more responsive…

[No_curebimmer]

Received the resonators from ONLYACTIVE …man, it’s always a pleasure working with them!

Weather has been crappy here in TX so I haven’t had chance to drive the beast much, but I’m looking forward to getting these installed at end of Feb.

[Vulpe]

I've been wondering for the longest time what the inside of the resonators looked like, thanks haha.

[n8dgr84]

Those turbulators will definitely cost a few hp but is well worth it for the improved, more OEM+ mellow note, IMO.

[No_curebimmer]

Originally Posted by n8dgr84

Those turbulators will definitely cost a few hp but is well worth it for the improved, more OEM+ mellow note, IMO.

Not too worried…I’m running a GTS tune (~500 bhp/460 tq). Regardless, even w/o the tune, compared to OEM, I have a much freer exhaust flow, not only due to EQ and no 2ndary cats, but also the Dinan muffler has a larger diameter than OEM piping.

Likely I won’t feel it. The resonators should lower the frequency (deeper rumble), remove that cabin buzzing (droning) when cruising + ‘downshifting raspberry’ aka intermittent raspiness.

I have taken in-cabin vids of my current setup, need to post them shortly …

[n8dgr84]

The resonators won't do much for the "deepness" of the frequency or drone - that is mostly done by the pipe diameter and higher flow rate with the Dinan can.
However, they will reduce SPL a couple dB, mellow the tone and take the edge off of unwanted raspiness. I will be interested to know if they will affect drone - I suspect very slightly.

[No_curebimmer]

Originally Posted by n8dgr84

The resonators won't do much for the "deepness" of the frequency or drone - that is mostly done by the pipe diameter and higher flow rate with the Dinan can.
However, they will reduce SPL a couple dB, mellow the tone and take the edge off of unwanted raspiness. I will be interested to know if they will affect drone - I suspect very slightly.

What is interesting is the level of impact the items below have on cabin drone/buzzing :

1. MHD tune burble settings
2. BimmerLink sound tuning

Recently, I have burble mngmt enabled in MHD but zeroed out both aggressiveness and duration. BimmerLink sound tuning is enabled. Previously, I had sound tuning disabled with MHD burbles mngmt to 1% aggressive/duration- which resulted in noticeable cabin drone.

Now today, I was on my way to an appointment (spirited hwy driving and cruising), and I haven’t experienced any droning (I always drive in S+ mode), so that didn’t bother me. Today my car seems quiter than usual , but I suppose the MHD/Sound Tuning tweaks minimized droning.

However, “downshifting farts” remained…and that was always present; , that honestly is my biggest complaint.

So my appointment with my trusty muffler/weld shop is next week: I will have them remove any clamps (except those at the down pipes) and weld most everything to ensure zero exhaust leaks or loose fittings.

If my dB levels decrease as a result of the resonators, but I will gain a more controlled exhaust flow (min raspiness or raspberry sounds) - so be it, and that will be a win in my book.

Will continue to document my journey and post vids…

[e90m3808]

Will be interesting to hear if the resonators resolve that 2k downshift fart.

[No_curebimmer]

Oh ho …sounds soo good, whatcha boys and girls think?!

Not a pro videographer, but this is my first in cabin vid, redlined, windows down. Sure, inferior quality, but since I have 3 pedals, had to resort placing my iPhone 12Pro on a mount. Gotta get me a GoPro

https://youtube.com/shorts/QWgkXcPFgwM?feature=share

This was in S+, which has been my 99% driving mode.

[No_curebimmer]

Interesting thing happened today.

I haven’t really trusted myself, but for giggles…went for S+ and MDM mode. We all know MDM has 1/2 of the DSC nanies on, but dayum…me thinks the exhaust note is different than S+ alone… and so is the engine response, both for the better!

IIRC, from a sound perspective, MDM just keeps the flaps fully open all the time, nothing else since its thing is handling. How is that different than forcing the flaps open via MHD tune?

Now I’m rethinking the resonators idea . Not the easiest to remove since I am planning on welding everything