Equal-length exhaust discussion: new S55 sounds

[Kilabyte]

Originally Posted by RugbyBro

Where are they holding you??? We’ll send help

[Mp3Supply]

Originally Posted by kindafrosty

In light of recent posts, I wanted let you folks know that ONLYACTIVE took care of me. Obviously this was an isolated incident; they did not intentionally ship the midpipe missing a weld, however I was overly frustrated as you all read. I don't believe I misrepresented Active in my posts, but I did not intend to paint Active in a bad light. While there was some miscommunication, Active promptly responded and solved my issue, and I would shop with Active again.

The fitment is perfect and the midpipe sounds glorious. There's much less rattle than my old VRSF dual midpipe. Looking forward to providing a long-term review in the future.

Big on you to come back and just close the loop.

[BMa703]

Will a dinan exhaust mate up to the EL midpipe without any cutting?

[Maryan425]

BMa703 It should mate up perfectly with no cutting. I have the same setup on my car currently with catless VRSF downpipes and resonated eq midpipe.

[BMa703]

Originally Posted by Maryan425

BMa703 It should mate up perfectly with no cutting. I have the same setup on my car currently with catless VRSF downpipes and resonated eq midpipe.

Awesome! Any rasp/drone with your setup?

[kindafrosty]

Non-res EL with stock downpipes and ZCP muffler so far is highly amusing driving above 3.5k RPM with the flaps open now, totally changed the sound of the car in a good way. Unfortunately though, I spoke too soon on the rattle aspect and I'm experiencing this heinous metallic/tin can buzzing noise on cold start, but ESPECIALLY when driving regardless of engine temp. It's seems to be a very common issue on the M2C forums (thread below). The video below (not mine) highlights the main problem that's started to happen when modulating throttle in the 1.5-3.5k RPM rev range; most midpipes you'd hear the "brraappp" sound, but this is just not harmonic. Happens with the flaps both open and closed. I won't lie, it's embarrassing and is potentially a deal breaker at it sits, so I'd love to find a solution. I didn't hear this issue on any of the M3/M4 non-res EL stock set-up videos, so confused as why I'm having the issue.

I'm going to readjust the install next week even though the fitment was great. Something could have expanded due to the first few heat cycles? Others have said it's the ZCP muffler design and/or valves vibrating, yet a few clips I've seen sounded great. Could try resonators or replace the muffler clamps with welds, really not sure. Anyone else had similar issues with a metallic buzzing noise when driving with non-res stock setup?

https://f87.bimmerpost.com/forums/sh....php?t=1837660

[rborane]

M4 with Non-res EQ with base muffler and OEM Downpipes, and I don't get any buzzing noises that sound anything like the video above.

[RugbyBro]

Originally Posted by kindafrosty

Non-res EL with stock downpipes and ZCP muffler so far is highly amusing driving above 3.5k RPM with the flaps open now, totally changed the sound of the car in a good way. Unfortunately though, I spoke too soon on the rattle aspect and I'm experiencing this heinous metallic/tin can buzzing noise on cold start, but ESPECIALLY when driving regardless of engine temp. It's seems to be a very common issue on the M2C forums (thread below). The video below (not mine) highlights the main problem that's started to happen when modulating throttle in the 1.5-3.5k RPM rev range; most midpipes you'd hear the "brraappp" sound, but this is just not harmonic. Happens with the flaps both open and closed. I won't lie, it's embarrassing and is potentially a deal breaker at it sits, so I'd love to find a solution. I didn't hear this issue on any of the M3/M4 non-res EL stock set-up videos, so confused as why I'm having the issue.

I'm going to readjust the install next week even though the fitment was great. Some have said it's the ZCP muffler design and valves, yet a few clips I've seen sounded great. Could try resonators or replace the muffler clamps with welds. I want to identify the noise source first before upgrading mufflers and potentially having the same issue. Anyone else had similar issues with a metallic buzzing noise when driving with non-res stock setup?

https://f87.bimmerpost.com/forums/sh....php?t=1837660

I get that rattle specifically in high gear low rpm situations. Like if I’m cruising at 35 in 5th gear and spinning like 1500 rpm and I lean into the gas a little bit. However I don’t get that in 1, 2, or 3 at that same RPM. It sounds extremely similar to when driving during cold start with the valves open, which has lead me to theorize that possibly at high gear low rpm cruising situations, the waste gates are open as there is very little boost needed and to prevent unnecessary turbine spinning. Could be completely wrong about that but having lived with the midpipe for a year, I’ve become very familiar with just about every kind of rattle imaginable lol and I can replicate that exact rattle in the video by doing the above

Edit: I do not have the rattle when in optimal gears for performance relative to speed - only when in suboptimal gears. With valves closed and stock muffler, I can’t hear any of the rattle (100% absorbed by the muffler)

[kindafrosty]

Originally Posted by RugbyBro

I get that rattle specifically in high gear low rpm situations. Like if I’m cruising at 35 in 5th gear and spinning like 1500 rpm and I lean into the gas a little bit. However I don’t get that in 1, 2, or 3 at that same RPM. It sounds extremely similar to when driving during cold start with the valves open, which has lead me to theorize that possibly at high gear low rpm cruising situations, the waste gates are open as there is very little boost needed and to prevent unnecessary turbine spinning. Could be completely wrong about that but having lived with the midpipe for a year, I’ve become very familiar with just about every kind of rattle imaginable lol and I can replicate that exact rattle in the video by doing the above

Edit: I do not have the rattle when in optimal gears for performance relative to speed - only when in suboptimal gears. With valves closed and stock muffler, I can’t hear any of the rattle (100% absorbed by the muffler)

Your edit makes a good point. The rattles don't occur much when I'm in D mode (DCT). So you're saying when I'm in S mode manually controlling gears I may not be at the right gear for the speed causing the metallic buzzing? Though I get the same tin buzzing noise with the flaps closed on cold start and when driving, it's still there but less pronounced with the flaps closed.

Would you say you have the same cold start and metallic buzzing noises as heard in these videos?

(this one occurs with an after market exhaust which scares me)

(buzz around 0:03-0:04)

[RugbyBro]

Originally Posted by kindafrosty

Your edit makes a good point. The rattles don't occur much when I'm in D mode (DCT). So you're saying when I'm in S mode manually controlling gears I may not be at the right gear for the speed causing the metallic buzzing? Though I get the same tin buzzing noise with the flaps closed on cold start and when driving, it's still there but less pronounced with the flaps closed.

Would you say you have the same cold start and metallic buzzing noises as heard in these videos?

(this one occurs with an after market exhaust which scares me)

(buzz around 0:03-0:04)

That sounds exactly like my cold start sequence. I think it’s a combo of the frequencies being pushed out, the design of the midpipe, and the waste gates being wide open on cold start (to warm the cats). I mainly attribute this rattle to the wastegates being open because if you start driving during the cold start, the rattle intensifies and makes and awful racket particularly if the valves are open (sport and sport+ valves are always open in 1st and 2nd). It goes away after the sequence is over. As for the second visit, that sound at the 0:03 mark isn’t the same rattle, that’s just the sound of the exhaust.

Edit: I’ll try and get some sound clips tmrw when I drive, I’m almost certain we are talking about the same rattle now. I can induce it at will haha

[kindafrosty]

Originally Posted by RugbyBro

That sounds exactly like my cold start sequence. I think it’s a combo of the frequencies being pushed out, the design of the midpipe, and the waste gates being wide open on cold start (to warm the cats). I mainly attribute this rattle to the wastegates being open because if you start driving during the cold start, the rattle intensifies and makes and awful racket particularly if the valves are open (sport and sport+ valves are always open in 1st and 2nd). It goes away after the sequence is over. As for the second visit, that sound at the 0:03 mark isn’t the same rattle, that’s just the sound of the exhaust.

Edit: I’ll try and get some sound clips tmrw when I drive, I’m almost certain we are talking about the same rattle now. I can induce it at will haha

Thank you so much. If you think it's the waste gates, why don't more people have the issue and how come many videos online don't have our cold start rattle? As for the second video, if you're saying 0:03 is normal, why I haven't I heard it in other non-res stock muffler clips? If we are talking about the same noise and it's not a design or my install error, I'm surprised you are able to live with it when driving with a warm engine. Today I drove a lot more and felt embarrassed especially downshifting in S2/S3 mode or when letting off gas slightly, all I get is this high-pitched metallic tin noise which is not gracious to the ears. Neither is the cold start but I can code that out once the warranty expires, or this winter. The upshifts above 3k RPM sound great as we all know, but if I manually shift (even in S1) around 2k RPM and keep lightly accelerating, I will hear the same metallic noise drone on for a second or so.

[TacoJova]

Anyone have a direct comparison of the Remus Rear versus the Dinan Rear all else being equal?

[Mp3Supply]

I have an EL AA Non-Res and I haven't been able to produce the sound in the first video you posted. My 3k RPM is quite deep a full and I haven't had any rattles or metal vibrations. I did have a local performance shop put it on so maybe they inspected all areas and adjusted. It really was a one and done thing and I was out the door and on my way.

There are times when the car isn't fully warm and if I downshift to 3rd to 2nd I can get a not-the-most pleasant sound but after the car is warm its a real deep & full sounding downshift from 3rd to 2nd at like 2.5k RPM.

Some of the latter videos you post sound like my normal cold start. I don't think there would be anyway to get rid of that besides removing cold start with BM3 or something else. (???, just a guess)

I will be swapping the back portion out to be resonated since I'm not a fan of the rasp at WOT but I don't expect any of that to change the tone.

Originally Posted by kindafrosty

Thank you so much. If you think it's the waste gates, why don't more people have the issue and how come many videos online don't have our cold start rattle? As for the second video, if you're saying 0:03 is normal, why I haven't I heard it in other non-res stock muffler clips? If we are talking about the same noise and it's not a design or my install error, I'm surprised you are able to live with it when driving with a warm engine. Today I drove a lot more and felt embarrassed especially downshifting in S2/S3 mode or when letting off gas slightly, all I get is this high-pitched metallic tin noise which is not gracious to the ears. Neither is the cold start but I can code that out once the warranty expires, or this winter. The upshifts above 3k RPM sound great as we all know, but if I manually shift (even in S1) around 2k RPM and keep lightly accelerating, I will hear the same metallic noise drone on for a second or so.

[ManBearBrett]

Originally Posted by Maryan425

BMa703 It should mate up perfectly with no cutting. I have the same setup on my car currently with catless VRSF downpipes and resonated eq midpipe.

So are you saying that a dinan axle back (and probably others) just mates up with the Mid pipe where as a stock exhaust or ZCP exhaust would require cutting because it's all one piece up to the downpipes?

[Slo_F80_Mike]

Originally Posted by RugbyBro

I get that rattle specifically in high gear low rpm situations. Like if I'm cruising at 35 in 5th gear and spinning like 1500 rpm and I lean into the gas a little bit. However I don't get that in 1, 2, or 3 at that same RPM. It sounds extremely similar to when driving during cold start with the valves open, which has lead me to theorize that possibly at high gear low rpm cruising situations, the waste gates are open as there is very little boost needed and to prevent unnecessary turbine spinning. Could be completely wrong about that but having lived with the midpipe for a year, I've become very familiar with just about every kind of rattle imaginable lol and I can replicate that exact rattle in the video by doing the above

Edit: I do not have the rattle when in optimal gears for performance relative to speed - only when in suboptimal gears. With valves closed and stock muffler, I can't hear any of the rattle (100% absorbed by the muffler)

It's weird because I get a weird rattle/ vibration noise on stock non zcp setup while high gear, low rpm. I thought it was just a characteristic of the car since I heard it on a m4 with like muffler delete and the noise was loud enough to hear/ feel next to him on highway windows up as well

[Maryan425]

Originally Posted by BMa703

Awesome! Any rasp/drone with your setup?

BMa703 There might be a minimal amount of rasp when letting the gas go under load but otherwise it is minimal and hasn’t been very noticeable. I will try to get some videos of the setup during this week. I will say that it is the best sounding setup I’ve heard comparing to all of the videos with catless downpipes.

Originally Posted by ManBearBrett

So are you saying that a dinan axle back (and probably others) just mates up with the Mid pipe where as a stock exhaust or ZCP exhaust would require cutting because it's all one piece up to the downpipes?

ManBearBrett The stock exhaust rather ZCP or non competition should mate with the eq length midpipe from AA with no issues. The dinan exhaust, zcp, and non comp stock exhaust all have the same measurements and would fit without modification (even to the stock midpipe). With these exhausts the axle back and midpipe are separate pieces.

I think where you would run into some issues requiring modification would be with the M performance exhaust, because the midpipe and axle back mate at a different point than the previously mentioned exhausts. I hope that helps clarify it a bit.

[Kilabyte]

Originally Posted by RugbyBro

I get that rattle specifically in high gear low rpm situations. Like if I’m cruising at 35 in 5th gear and spinning like 1500 rpm and I lean into the gas a little bit. However I don’t get that in 1, 2, or 3 at that same RPM. It sounds extremely similar to when driving during cold start with the valves open, which has lead me to theorize that possibly at high gear low rpm cruising situations, the waste gates are open as there is very little boost needed and to prevent unnecessary turbine spinning. Could be completely wrong about that but having lived with the midpipe for a year, I’ve become very familiar with just about every kind of rattle imaginable lol and I can replicate that exact rattle in the video by doing the above

Edit: I do not have the rattle when in optimal gears for performance relative to speed - only when in suboptimal gears. With valves closed and stock muffler, I can’t hear any of the rattle (100% absorbed by the muffler)

I have the same issue at ~1500RPM, but it only happens if I'm at more than 1/2 throttle, doesn't happen in normal driving.

[TractionControlDelete]

Originally Posted by kindafrosty

Non-res EL with stock downpipes and ZCP muffler so far is highly amusing driving above 3.5k RPM with the flaps open now, totally changed the sound of the car in a good way. Unfortunately though, I spoke too soon on the rattle aspect and I'm experiencing this heinous metallic/tin can buzzing noise on cold start, but ESPECIALLY when driving regardless of engine temp. It's seems to be a very common issue on the M2C forums (thread below). The video below (not mine) highlights the main problem that's started to happen when modulating throttle in the 1.5-3.5k RPM rev range; most midpipes you'd hear the "brraappp" sound, but this is just not harmonic. Happens with the flaps both open and closed. I won't lie, it's embarrassing and is potentially a deal breaker at it sits, so I'd love to find a solution. I didn't hear this issue on any of the M3/M4 non-res EL stock set-up videos, so confused as why I'm having the issue.

I'm going to readjust the install next week even though the fitment was great. Something could have expanded due to the first few heat cycles? Others have said it's the ZCP muffler design and/or valves vibrating, yet a few clips I've seen sounded great. Could try resonators or replace the muffler clamps with welds, really not sure. Anyone else had similar issues with a metallic buzzing noise when driving with non-res stock setup?

https://f87.bimmerpost.com/forums/sh....php?t=1837660

Sounds kind of good to me

[Mp3Supply]

kindafrosty

I tried to get a recording of mine on an iPhone 12 with no audio attachments. Basically its crap sounding on a phone so listen on your computer. I wasn't going to post it but after listening to it on the computer with real speakers, it sounded way better.

F80 Comp DCT
BM3 Stg 1; No Burbles
AA EL Mid Non-Resonated
ZCP Rear
Stock DPs

First Portion of the video is Automatic S2 Economy Transmission...
Return trip and the remainder of the video is Manual Sport +.

I didn't press more then 30-40% throttle since it was rattle pinging noises we were discussing.

[HotRodM4]

Installing the non res version tomorrow. So far, stock everything really. I mean I put the BMC filters, removed the charcoal filters, unplugged the ASD, and turned off the bubbles via Bimmerlink so far.

Can't wait.

Edit: This sounds amazing.

[Mp3Supply]

Originally Posted by HotRodM4

Installing the non res version tomorrow. So far, stock everything really. I mean I put the BMC filters, removed the charcoal filters, unplugged the ASD, and turned off the bubbles via Bimmerlink so far.

Can't wait.

Edit: This sounds amazing.

Sounds good inside.

My phone is always falling over in the cup holder too.

[kindafrosty]

I was able to fix the low-speed vibration issue, ended up being the heat shield making contact with the midpipe. Tight clearance for sure.

This thing sounds incredible 90% of the time, but the other 10% I still cannot figure out this metallic buzzing issue at lower RPMs. I found a video (below) that emulates my issue. Mine does not sound nearly as bad as the video below since he's catless, but it's close and not harmonic as you can hear. I thought resonators may help, but he has resonators and that same metallic buzz is still there.

Here's a video I took and the buzz sound is almost identical when upshifting www.youtube.com/watch?v=S6aBn8DtR_g

Keep in mind it only happens at certain low RPMs. It could be the anti-lag system combined with the resonance of the zcp muffler. While that makes sense to me, there's not many others talking about this "sound" which makes be believe there's other variables, maybe even my throttle position? Also hard to compare when there's very few videos of the AA EL driving around civilly, mainly high RPM pulls or neutral revs.

Before I throw further money into this fire with a new muffler, resonators, or go back to stock, am I really the odd one out here? Or is this a common issue with you stock dp non-res ZCP muffler folk when driving around town normally? I am petrified of the thought of this metallic buzzing noise becoming worse once the cold weather comes, so any thoughts or feedback would be appreciated