OEM muffler bypass mod, anyone regret it?

Newb17 · 08-03-2015, 07:30 PM

Stock mufflers are very underwhelming. Torn between the 4 pipe non perforated or bypass method. Is the bypass a lot louder than the 4 pipe?

Sered · 08-03-2015, 08:08 PM

They regret it when they get testpipes lol

Ezio · 08-03-2015, 08:13 PM

4 pipe and bypass are near same.

Helmsman · 08-05-2015, 04:07 AM

Quote:

Originally Posted by Newb17

Stock mufflers are very underwhelming. Torn between the 4 pipe non perforated or bypass method. Is the bypass a lot louder than the 4 pipe?

I started with 2-pipe only. Significant difference, haven't thought a second about the additional 2 pipes since.

Cheers

ashtaron14 · 08-05-2015, 04:22 AM

I did the perforated method (2 pipes) and feel that it's good enough.

I'm pondering the test pipe, but I have not heard the perforated method with the test pipes; whereas the ACM method with test pipes, is...

Just have a shop take off the muffler and drive around the block, I think that's about similar sound to test pipes and bypass.

DBE · 08-05-2015, 05:05 AM

I have thr 2 pipe. Want more because im greedy. 4 pipe booked for tomorrow

Move Over · 08-05-2015, 07:22 AM

I have 4 pipe and love it. When I go test pipes, I'm having resonators welded in place.

Newb17 · 08-05-2015, 11:47 AM

I'm leaning towards the bypass(ACM) mod.

///M Power-Belgium · 08-05-2015, 12:20 PM

Quote:

Originally Posted by Newb17

I'm leaning towards the bypass(ACM) mod.

Question...
Do you want drone...Yes or no ?

Newb17 · 08-05-2015, 12:28 PM

Quote:

Originally Posted by ///M Power-Belgium

Question...
Do you want drone...Yes or no ?

I want a noticeably louder exhaust than factory, all around. If there's some drone with the bypass, I'm ok with that. What I'm really wondering about is the volume difference between the 4 pipe and bypass. If there's very little difference, I'd go with the 4 pipe.

zipsonic · 08-05-2015, 01:24 PM

I just (like 5 days ago) replaced mine with ACM bypass method. It's much louder. I do not regret this. Also low speed cruising its hardly noticeable, so it won't affect your neighbors. 5-8K @ WOT its a beast. Like a Ferrari and some old V8's love child. It really changes the character of the car.

Newb17 · 08-05-2015, 01:27 PM

Quote:

Originally Posted by zipsonic

I just (like 5 days ago) replaced mine with ACM bypass method. It's much louder. I do not regret this. Also low speed cruising its hardly noticeable, so it won't affect your neighbors. 5-8K @ WOT its a beast. Like a Ferrari and some old V8's love child. It really changes the character of the car.

Thanks! Were you stock before the ACM? 2 pipe? 4 pipe?

///M Power-Belgium · 08-05-2015, 01:27 PM

Quote:

Originally Posted by Newb17

I want a noticeably louder exhaust than factory, all around. If there's some drone with the bypass, I'm ok with that. What I'm really wondering about is the volume difference between the 4 pipe and bypass. If there's very little difference, I'd go with the 4 pipe.

Between 4 pipe and bypass (ACM) is very little difference , almost none.
With the 2 big and all 4 perforated pipe replacement method, the Helmholtz chambers are still intact and functional .
Helmholtz chambers are designed by BMW and are anti-drone and unique because our Oem exhaust is a very good exhaust and also double walled .
With the bypass or ACM method the Helmholtz chamber function is deleted because the pipes going now straight through and so the exhaust will drone at low rpm's .
My thread because I've done this mod. by myself => http://www.m3post.com/forums/showthread.php?t=733817

There is also something like sound quality ..And for me personal the bypass sounds like a broken exhaust with lack of sound quality ,while the 2 big or all 4 method just sounds amazing .
In the video you can hear the 4 pipe method...

Newb17 · 08-05-2015, 01:34 PM

Quote:

Originally Posted by ///M Power-Belgium

Between 4 pipe and bypass (ACM) is very little difference , almost none.

Good to know.

Quote:

Originally Posted by ///M Power-Belgium

There is also something like sound quality ..And for me personal the bypass sounds like a broken exhaust with lack of sound quality.

Can you try explain what a broken muffler sounds like to you? I would think the ACM sound quality is very close to the M performance exhaust(minus the drone) being it's straight through as well.

Quote:

Originally Posted by ///M Power-Belgium

In the video you can hear the 4 pipe method...

Sounds very good.

///M Power-Belgium · 08-05-2015, 01:53 PM

Quote:

Originally Posted by Newb17

Good to know.

Can you try explain what a broken muffler sounds like to you? I would think the ACM sound quality is very close to the M performance exhaust(minus the drone) being it's straight through as well.

Sounds very good.

How a broken exhaust sounds ?
Never heard a 20 year old car ? (Sounds like shit )

///M Performance ?
Sounds too hollow it's typical for exhausts made from titanium and inconel , it's like you scream through an empty barrel .
And ACM sounds no way like the ///M Performance .
Here an example....///M Performance vs the Oem exhaust mod. ( the 2 big perforated method)

Newb17 · 08-05-2015, 01:57 PM

Quote:

Originally Posted by ///M Power-Belgium

How a broken exhaust sounds ?
Never heard a 20 year old car ? (Sounds like shit )

///M Performance ?
Sounds too hollow it's typical for exhausts made from titanium and inconel , it's like you scream through an empty barrel .
And ACM sounds no way like the ///M Performance .
Here an example....///M Performance vs the Oem exhaust mod. ( the 2 big perforated method)

I actually went and listened to sound clips of the M performance before I read this reply. First thing that came up mind, sounds hollow. 4 pipe it is. Going tomorrow. Thanks for your input.

///M Power-Belgium · 08-05-2015, 02:01 PM

Quote:

Originally Posted by Newb17

I actually went and listened to sound clips of the M performance before I read this reply. First thing that came up mind, sounds hollow. 4 pipe it is. Going tomorrow. Thanks for your input.

Exactly !

Let me know...Or just PM me .

zipsonic · 08-05-2015, 02:40 PM

Quote:

Originally Posted by Newb17

Thanks! Were you stock before the ACM? 2 pipe? 4 pipe?

It was stock. I have no intentions of making any other changes to the exhaust system because I am so happy with this mod.

I was concerned that I wouldn't like it, so I bought an extra stock muffler to do the mod. There really was no need.

Newb17 · 08-05-2015, 03:01 PM

Quote:

Originally Posted by zipsonic

It was stock. I have no intentions of making any other changes to the exhaust system because I am so happy with this mod.

I was concerned that I wouldn't like it, so I bought an extra stock muffler to do the mod. There really was no need.

Going with the 4 pipe. Don't want any drone.

///M Power-Belgium · 08-05-2015, 03:44 PM

Quote:

Originally Posted by Newb17

Going with the 4 pipe. Don't want any drone.

08-03-2015, 07:30 PM	#1
Newb17 Private 45 Rep 93 Posts Drives: 2003 z06 Join Date: Sep 2013 Location: United States iTrader: (0)	OEM muffler bypass mod, anyone regret it? Stock mufflers are very underwhelming. Torn between the 4 pipe non perforated or bypass method. Is the bypass a lot louder than the 4 pipe?
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08-03-2015, 08:08 PM	#2
Sered Major 154 Rep 1,201 Posts Drives: 08 E90 335i Join Date: Apr 2012 Location: Melbourne, FL iTrader: (3)	They regret it when they get testpipes lol
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08-03-2015, 08:13 PM	#3
Ezio Brigadier General 802 Rep 4,224 Posts Drives: 2026 M4 Join Date: Nov 2012 Location: MI iTrader: (0)	4 pipe and bypass are near same.
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08-05-2015, 04:22 AM	#5
ashtaron14 Major 1176 Rep 1,082 Posts Drives: G80 M3 Join Date: Jun 2011 Location: HK iTrader: (0)	I did the perforated method (2 pipes) and feel that it's good enough. I'm pondering the test pipe, but I have not heard the perforated method with the test pipes; whereas the ACM method with test pipes, is... Just have a shop take off the muffler and drive around the block, I think that's about similar sound to test pipes and bypass. __________________ My G80 M3 Follow me on IG
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08-05-2015, 05:05 AM	#6
DBE First Lieutenant 90 Rep 341 Posts Drives: 08 E92 M3 Join Date: May 2012 Location: Brisbane iTrader: (0)	I have thr 2 pipe. Want more because im greedy. 4 pipe booked for tomorrow
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08-05-2015, 07:22 AM	#7
Move Over Colonel 1316 Rep 2,496 Posts Drives: M3 6MT Join Date: May 2015 Location: Peninsula iTrader: (9)	I have 4 pipe and love it. When I go test pipes, I'm having resonators welded in place.
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08-05-2015, 11:47 AM	#8
Newb17 Private 45 Rep 93 Posts Drives: 2003 z06 Join Date: Sep 2013 Location: United States iTrader: (0)	I'm leaning towards the bypass(ACM) mod.
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08-05-2015, 01:24 PM	#11
zipsonic New Member 5 Rep 29 Posts Drives: 2011 e93 M3 Join Date: Oct 2014 Location: Los Angeles, CA iTrader: (1)	I just (like 5 days ago) replaced mine with ACM bypass method. It's much louder. I do not regret this. Also low speed cruising its hardly noticeable, so it won't affect your neighbors. 5-8K @ WOT its a beast. Like a Ferrari and some old V8's love child. It really changes the character of the car.
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08-06-2015, 04:50 AM	#22
DBE First Lieutenant 90 Rep 341 Posts Drives: 08 E92 M3 Join Date: May 2012 Location: Brisbane iTrader: (0)	Went from 2 pipe to 4 today. I was worried itd be over the top but actually its just like the 2 pioe with a bit more volume. Sounds great, low rasp, low drone and cheap as chips
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