Buzzing Noise at 2k RPM after AA EL Midpipe

[victorboost]

I recently purchased and had an Active Autowerke EL Resonated midpipe installed into my F80 M3. The midpipe is mated with stock ZCP Muffler and Gintani Downpipe.

As soon as I got it installed, I noticed an annoying buzzing noise. Sounds like a straight piped civic but only at 1700-2100 rpm and then completely goes away. This only happens under load while accelerating, and I cannot replicate this issue while in park revving. The buzzing also is significantly louder when the muffler valves are open.

I have brought it back to the shop a few times and have made slight adjustments for fitment etc. as far as I know now, there is no contact between the heat shield and the pipe, as well as the DP to midpipe gasket is in decent shape. The gintani downpipe is catless and the shop is blaming the buzzing on the fact the downpipe is catless. (Midpipe is resonated btw)

My clutch recently went out and had to drop the transmission to replace the clutch. Part of the process is dropping the midpipe so I figured the buzzing was due to faulty installation and having it installed by a different people this time around may fix it. However the buzzing is still there.

If anybody has any pointers would be very appreciated, this has been driving me crazy

[TopJimmy]

It's still likely to be a heat shield. Just use a small pry bar to gently push them up a little where it looks really tight. Or double some cardboard to make a spacer and see if you can slide it along the top of the pipes, from front to back. If it feels tight or gets stuck there's a spot to work more clearance.

[mike@x-ph.com]

Originally Posted by TopJimmy

It's still likely to be a heat shield. Just use a small pry bar to gently push them up a little where it looks really tight. Or double some cardboard to make a spacer and see if you can slide it along the top of the pipes, from front to back. If it feels tight or gets stuck there's a spot to work more clearance.

+1 I had the same issue.

I readjusted the install and it fixed the issue right away

[2sporty]

Sorry brother, but it's absolutely not the heat shields. It's the AA EL midpipe, itself. Check out this thread where people who buy the midpipe become salespeople for it, even though they know it turns your car into a straight piped civic. And they delude themselves into thinking it was worth the investment even though we all know it sounds like a straight piped civic.

https://f80.bimmerpost.com/forums/sh....php?t=1893796

[PandaxF82]

Any possibility of recording a sound clip. I think that would help us help you diagnose.

[victorboost]

Originally Posted by PandaxF82

Any possibility of recording a sound clip. I think that would help us help you diagnose.

Here is a clip boss. Valves open once the TC and MDM lights go on. Right in that 1700-2100 rpm range that the buzzing happens.

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

[victorboost]

Bump

[victorboost]

bump help please!!

[M3god]

Originally Posted by victorboost

bump help please!!

Either get a brace for the midpipe or it's the actuator clip that needs replacement

[RoundelM3]

FYI, you have TWO downpipes...if you didn't replace the "doughnut" gaskets where the midpipe joins the downpipes, that's one other thing to check.

[victorboost]

Originally Posted by RoundelM3

FYI, you have TWO downpipes...if you didn't replace the "doughnut" gaskets where the midpipe joins the downpipes, that's one other thing to check.

I forgot to add that the rasp is also there on startup. In that case would it point to the gaskets? I would assume the change in exhaust pressure on startup and accelerating under load is enough to cause the buzzing, but when revving without any load it doesn't buzz.

[mapster37]

Youre going to have to get your vehicle on a lift and inspect the entire exhaust system. The AA EL midpipe is a very tight fit...

[victorboost]

Originally Posted by mapster37

Youre going to have to get your vehicle on a lift and inspect the entire exhaust system. The AA EL midpipe is a very tight fit...

Is it possible that the pipe itself just causes the buzzing? I'm pretty confident there are no points of contact with the pipe and any parts of the under carriage.

[PandaxF82]

1. Check all flange and gaskets on your downpipes, and midpipe to exhaust. These gaskets should have been all replaced and should be replaced anytime you put on new downpipes or any exhaust hardware to ensure proper fit and optimal airflow.

2. Check the valves on the stock exhaust. You're running additional airflow now and creating more back pressure. This may create additional pressure from the air flow to the stock muffler.

3. If the sound is coming from the front, of the car. Run a diagnostic of your wastegate alignment. Over time, your wastegate actuators can move out of alignment and create some fluttering as well.

[2sporty]

Originally Posted by victorboost

I forgot to add that the rasp is also there on startup. In that case would it point to the gaskets? I would assume the change in exhaust pressure on startup and accelerating under load is enough to cause the buzzing, but when revving without any load it doesn't buzz.

Yes this is classic AA EL midpipe with the lawnmower sound at start-up and at low RPMs and high gears. It's also definitely the pipe because you said the valves open make it worse. This is CLASSIC AA EL midpipe behavior. Also, your video was terrible, it did not make the sound apparent at all. Get a better mic or don't post it and confuse everyone. The sound, in person, is much more apparent than in your video. It's the pipe itself, which I already told you, yet you keep wanting to come up with another reason for it because you've purchased the pipe and you're "invested" in it. Everyone who has the pipe knows damn right it's the pipe and a lot of people don't want to say it because they've "invested" in it. Any half-witted semi-competent installer would check the heat shielding gap before handing the car over to you. On the M2 forums, there is a long thread about the lawnmower sound at start-up and at low RPMs. If you don't believe me, go there and read it.

[PandaxF82]

Why have cold start when you're Catless? Disable it. Doesn't make any sense.

[victorboost]

Originally Posted by PandaxF82

Why have cold start when you're Catless? Disable it. Doesn't make any sense.

I don’t have cold start warm up. On startup it just revs up to 1500 and immediately drops to 600 rpm idle.

[victorboost]

Originally Posted by 2sporty

Yes this is classic AA EL midpipe with the lawnmower sound at start-up and at low RPMs and high gears. It's also definitely the pipe because you said the valves open make it worse. This is CLASSIC AA EL midpipe behavior. Also, your video was terrible, it did not make the sound apparent at all. Get a better mic or don't post it and confuse everyone. The sound, in person, is much more apparent than in your video. It's the pipe itself, which I already told you, yet you keep wanting to come up with another reason for it because you've purchased the pipe and you're "invested" in it. Everyone who has the pipe knows damn right it's the pipe and a lot of people don't want to say it because they've "invested" in it. Any half-witted semi-competent installer would check the heat shielding gap before handing the car over to you. On the M2 forums, there is a long thread about the lawnmower sound at start-up and at low RPMs. If you don't believe me, go there and read it.

I’m willing to accept it and take the L, just confused why some people running same setup and don’t have this issue..

[RugbyBro]

Sounds like something is possibly not bolted down tightly or valve rattle, any way you can get a better sound clip? It’s a little hard to tell on the one you’ve posted but I can just make out what you’re talking about. I don’t have that sound on either cars I’ve run EL on. There are some quirks to S55 that EL exacerbates but not this one

[whitedc5]

Originally Posted by 2sporty

Yes this is classic AA EL midpipe with the lawnmower sound at start-up and at low RPMs and high gears. It's also definitely the pipe because you said the valves open make it worse. This is CLASSIC AA EL midpipe behavior. Also, your video was terrible, it did not make the sound apparent at all. Get a better mic or don't post it and confuse everyone. The sound, in person, is much more apparent than in your video. It's the pipe itself, which I already told you, yet you keep wanting to come up with another reason for it because you've purchased the pipe and you're "invested" in it. Everyone who has the pipe knows damn right it's the pipe and a lot of people don't want to say it because they've "invested" in it. Any half-witted semi-competent installer would check the heat shielding gap before handing the car over to you. On the M2 forums, there is a long thread about the lawnmower sound at start-up and at low RPMs. If you don't believe me, go there and read it.

We get it bro, you don't like the EL midpipe and the owners of the pipe make you very upset. Try not to get too worked up over it, it's just a pipe.

[2sporty]

Originally Posted by victorboost

I’m willing to accept it and take the L, just confused why some people running same setup and don’t have this issue..

Believe me, they all have it. It's like having STDs and just not talking about it because they paid for it.

[2sporty]

Originally Posted by whitedc5

We get it bro, you don't like the EL midpipe and the owners of the pipe make you very upset. Try not to get too worked up over it, it's just a pipe.

^^^
Look at this guy, for example. Go to any M3/4 meet and these people will deny, IN YOUR FACE, that they have any buzzing noises or red bumps on their weenie. Then, when they drive off or cold start their car, you'll hear it. That undeniable ear-wrenching noise. They were in denial, or deaf. Civic EG hatch straight piped directly into your ear. And they'll call it an EG3/6 rather than a Civic just so you know how cool it is.