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M2 Technical Topics > N55 Engine / Drivetrain / Exhaust / Bolt-ons / Tuning > Reason for Comfort to Sport Sound Change

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      12-01-2016, 07:11 PM   #1
jiaming927
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Reason for Comfort to Sport Sound Change

Hi,
I noticed that the car changes its exhaust sound when I switch from comfort mode to sport mode (no burble to has burble). I thought the reason for the burble is those flaps I have in MPE, but when I open the flaps (track mode on MPE) the sound gets even louder, does this mean there are two layers of flaps? Or is the burble the result of engine being in sport mode? Very curious..
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      12-02-2016, 08:15 AM   #2
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I thought the burble was due to unburnt fuel?
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      12-02-2016, 08:28 AM   #3
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Originally Posted by zenmaster View Post
I thought the burble was due to unburnt fuel?
I believe you are correct, my understanding is the fuel map changes from comfort to sport which creates this effect. I have to say I love the sound of the M2.
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      12-02-2016, 08:38 AM   #4
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Yes, the engineers obviously had an objective to create a good exhaust sound on this car! No fanboy, but have to say I like what they did - has its own character. Had a concern it would be obnoxious cruising around town, but not the case.
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      12-02-2016, 12:23 PM   #5
jiaming927
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Yeah that's probably the reason. I read this: https://www.quora.com/Why-do-modern-...n-the-over-run and I thought it's due to flaps.
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      12-03-2016, 04:03 AM   #6
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Current vehicles have this engineered in. Cars like the F-Type, Focus RS and also the M2 have been engineered like this.

In case of the F-Type they spray a little bit of fuel in the beginning of the exhaust near the manifold that ignites in the exhaust and you gets you the burbles. At least that is what an engineer at Jaguar told me.

More and more cars have some kind of system engineered in and by changing the mode on the car the system inside change and give you a different exhaust note.

It could well be there is a second flap some cars, but I did not see this flap when I changed my exhaust at Akrapovic. There was nothing there other than the turbo and then the downpipe.

MR
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      12-04-2016, 01:24 PM   #7
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When the flaps open your sound changes because its bypassing the muffler. Maybe they do some stuff with tune too.
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      12-04-2016, 01:41 PM   #8
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Quote:
Originally Posted by jiaming927 View Post
Hi,
I noticed that the car changes its exhaust sound when I switch from comfort mode to sport mode (no burble to has burble). I thought the reason for the burble is those flaps I have in MPE, but when I open the flaps (track mode on MPE) the sound gets even louder, does this mean there are two layers of flaps? Or is the burble the result of engine being in sport mode? Very curious..
press the DSC button if you like even more burbles, traction lights up in the instrument cluster, the is M Dynamic mode, tons of snap, crackle and pop
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      12-05-2016, 11:24 AM   #9
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Quote:
Originally Posted by jiaming927 View Post
Hi,
I noticed that the car changes its exhaust sound when I switch from comfort mode to sport mode (no burble to has burble). I thought the reason for the burble is those flaps I have in MPE, but when I open the flaps (track mode on MPE) the sound gets even louder, does this mean there are two layers of flaps? Or is the burble the result of engine being in sport mode? Very curious..
If i am not mistaken there are 2 set of flaps as you have the M performance exhaust. The stock car comes from the factory with flaps which open/close depending on the mode selection and are situated in front the end exhaust box. The m performance exhaust has a different end-box and additional flaps which sit behind the end-box and you can control from the Bluetooth controller and even see them operate if you look in the exhaust tips.
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      12-07-2016, 12:29 PM   #10
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Quote:
Originally Posted by M2ME2 View Post
press the DSC button if you like even more burbles, traction lights up in the instrument cluster, the is M Dynamic mode, tons of snap, crackle and pop
I am gonna try this today
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      12-07-2016, 05:00 PM   #11
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Correct! There is different mapping between each mode which changes the amount of snap crackles and pops the M2 makes!
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