Buzzing Noise at 2k RPM after AA EL Midpipe

[Shubacca]

You could look into this too, wouldn't hurt:

https://www.bimmerpost.com/forums/sh...php?p=29101970

[MineralWhiteF80]

Im going to add something here that you should at least check and rule out:

I had the small thin metal bracket that connects the bank 1 and bank 2 pipes on the AA EQ midpipe break on one side of the welds and it caused a buzzing rattle sound. I felt like I checked all heat shields, center support clearance, and all exhaust clearance several times and it made no difference.

After a fair bit of banging around on the exhaust with a mallet, i was finally able to A) get the exhaust to make a slight rattle and B) get a rough idea of where it was coming from.

I inspected that first connecting bracket at microscope level and found what looked to be a small stress fracture at the weld. This was a TINY crack that was very hard to even notice.

Turns out the weld was 99.9% broken but still looked like it was intact. I bent the bracket up and away from the broken weld side and my buzzing rattle was gone forever.

As of right now with stock down pipes, equal length resonated mid pipe, and MPE exhaust with valves forced open all the time and no cold start, I have ZERO rattles, buzzing, or any other issue whatsoever with my exhaust.

See attached picture for bracket im talking about

[F82be]

After installing my akrapovic with the EL i had the exact same noise, really loud buzzing/rattle around 1800-2200rpm on load.

Checkt everything, nothing loose or hitting. Muffler valves I rouled out because the buzzing/rattle got louder with valves open.

Next i changed my downpipes with oem cats AND rattle went completely away or atleast that I can hear inside the cabin..

But i'm 99% sure it's the wastegate's and not the midpipe that make the rattle noise like some here say

Looked on bootmod live data and the rattle started when the wastegate's start to go open till about 90% ( % value goes down the more they open)

Checkt the wastegate's and sure enough there's quit a bit of play on them..

However I do find it a bit strange that oem cats mute the wastegate rattle that much?

Never heard (or noticed) it with my MPE probably because off the second cats & MPE naturally tincan'ish sound

[F82be]

Soundclips off the rattle/buzzing I had


https://youtube.com/shorts/PCg47pI3cE8?feature=share




https://youtube.com/shorts/zK-QJj2Vh_E?feature=share

[M4J0R T0M]

Originally Posted by MineralWhiteF80

Im going to add something here that you should at least check and rule out:

I had the small thin metal bracket that connects the bank 1 and bank 2 pipes on the AA EQ midpipe break on one side of the welds and it caused a buzzing rattle sound. I felt like I checked all heat shields, center support clearance, and all exhaust clearance several times and it made no difference.

After a fair bit of banging around on the exhaust with a mallet, i was finally able to A) get the exhaust to make a slight rattle and B) get a rough idea of where it was coming from.

I inspected that first connecting bracket at microscope level and found what looked to be a small stress fracture at the weld. This was a TINY crack that was very hard to even notice.

Turns out the weld was 99.9% broken but still looked like it was intact. I bent the bracket up and away from the broken weld side and my buzzing rattle was gone forever.

As of right now with stock down pipes, equal length resonated mid pipe, and MPE exhaust with valves forced open all the time and no cold start, I have ZERO rattles, buzzing, or any other issue whatsoever with my exhaust.

See attached picture for bracket im talking about

How many miles were on your EL when this developed?

[M4J0R T0M]

Originally Posted by F82be

Soundclips off the rattle/buzzing I had


https://youtube.com/shorts/PCg47pI3cE8?feature=share




https://youtube.com/shorts/zK-QJj2Vh_E?feature=share

So after installing my Arm resonated DP's, AA EL res mids to my ZCP muffler I have the dreaded buzz at 2k RPMs. At first, I just noticed it on cold starts, and then it would go away. Now it comes back under hard acceleration after it warms up, but only under load typically. If I'm driving hard it will also do it as I'm revving past 3k as well.

I haven't had a chance to get up under the car and check everything out but I'm hoping to be able to do so in the next couple of weeks. I'll report back with what works or didn't work.

For the record, I've probably got about 1500 miles on my setup now.

[F82be]

Originally Posted by M4J0R T0M

So after installing my Arm resonated DP's, AA EL res mids to my ZCP muffler I have the dreaded buzz at 2k RPMs. At first, I just noticed it on cold starts, and then it would go away. Now it comes back under hard acceleration after it warms up, but only under load typically. If I'm driving hard it will also do it as I'm revving past 3k as well.

I haven't had a chance to get up under the car and check everything out but I'm hoping to be able to do so in the next couple of weeks. I'll report back with what works or didn't work.

For the record, I've probably got about 1500 miles on my setup now.

Hope it's not the wastegate's like mine. You can easily check them from the top takes 10mins, Just need to remove airbox.

However mine was always there cold or hot, soft or hard acceleration also when downshifting or overrun but strangely always/only around 2k RPM but i only drove it for maybe 20miles so I didn't really got a good hear of the buzz/rattle thru the rev range

[M4J0R T0M]

Originally Posted by F82be

Hope it's not the wastegate's like mine. You can easily check them from the top takes 10mins, Just need to remove airbox.

However mine was always there cold or hot, soft or hard acceleration also when downshifting or overrun but strangely always/only around 2k RPM but i only drove it for maybe 20miles so I didn't really got a good hear of the buzz/rattle thru the rev range

I’ll check them out, what am I looking for?


Oddly enough, I drove my car this morning and it didn’t buzz at all, hot or cold.

[victorboost]

Just a little update: after swapping my axle-back muffler, the buzzing was still there so I figured the culprit was my downpipe. I noticed that everybody running a VRSF downpipe had no issues, and so I figured that any downpipe with a flex joint will create that buzzing when paired with the EL midpipe.

I swapped my gintani downpipe with SSR downpipes, and the sound is almost entirely gone. I believe VRSF downpipes should clear the buzzing almost entirely. Hope this helps!

[e90m3808]

To everyone who has resolved the 2k rasp- are you all using the resonated connecting pipes?

[Joy15779]

My friends... I have an Akra DP Skat, I HAD OPF and stock terminal then my tuner removed OPF and replaced with REMUS (?) Mid......

It' s something I cannot held.. TOO much noise and too much pollution, the air coming out is pure cancer. I' going to come back to OPF if you don't have better suggestion,
Please consider my car is stage 3/4. Bigger kratos turbo, eventuri, Dorch, injectors, coils , bla bla. Will I loose something in power replacing OPF? According to my personal point of view peanuts only

[Soul Coughing]

An update for people: I had a vibration/resonance on cold start with the AA mid pipe non-resonated. It would happen in the first couple minutes of a drive - not all the time, but it didn't sound great. I assumed it had something to do with the cold start sequence/wastegate's, as it wouldn't happen with a warm start. Well I turned off the cold start sequence and now the car has no vibration/resonance when i first start the car. It is night and day in how different it sounds and is much better!

[Joy15779]

Originally Posted by Soul Coughing

An update for people: I had a vibration/resonance on cold start with the AA mid pipe non-resonated. It would happen in the first couple minutes of a drive - not all the time, but it didn't sound great. I assumed it had something to do with the cold start sequence/wastegate's, as it wouldn't happen with a warm start. Well I turned off the cold start sequence and now the car has no vibration/resonance when i first start the car. It is night and day in how different it sounds and is much better!

Cold start utilises a different stechio. Like in old cars when you pull air, do you recall?