U78 exhaust flaps
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From: Keep it simple - keep it OEM
AMG C63s Coupe
U78 exhaust flaps
Hello Boys & Girls,
are the exhaust flaps fully (100%) open
when you press the button in the center console?
Does anyone know how to activate emotion start?
Cu
are the exhaust flaps fully (100%) open
when you press the button in the center console?
Does anyone know how to activate emotion start?
Cu
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2019 C63CS
No. How far they open depends on the rpm. There’s an aftermarket module you can install that keeps them fully open at all times.
Emotion Start is described in the owner’s manual. You just press and hold one of the shift paddles and then start the engine. The feature only exists in the 2019+ FL models.
Emotion Start is described in the owner’s manual. You just press and hold one of the shift paddles and then start the engine. The feature only exists in the 2019+ FL models.
Last edited by superswiss; Jan 15, 2026 at 03:53 PM.
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2019 C63CS
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From: Keep it simple - keep it OEM
AMG C63s Coupe
The elec-drive rear flaps can technically only be fully closed or fully open. That is that was told to me and it sound logical.
On this point this aftermarket module seams like fake agent ?!
Last edited by C63s_Jack; Jan 26, 2026 at 08:50 AM.
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From: Keep it simple - keep it OEM
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Good question - now we have two claims about how the flaps work.
Interesting topic.
But we will find it out.
If WIS noting says then is the oem mechanism to check how it works.
Hmmm - if you start engine or allways ?
Interesting topic.
But we will find it out.
If WIS noting says then is the oem mechanism to check how it works.
Hmmm - if you start engine or allways ?
Last edited by C63s_Jack; Jan 26, 2026 at 08:48 AM.
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2021 C63S AMG
I have the Renntech EVM. It comes with a small electronic fob where setting 1 is EVM active and setting 2 is stock sound. At idle, in any drive mode, the sound character and volume are very different with the module active. While driving, same thing - volume and tone are dramatically different. Prior to installing the module, the sound was relatively tame except under acceleration with 'quiet mode' turned off.
The module remains active or inactive during engine startup based on whatever setting you used last. Hopefully that answers your question! I can't confirm exactly which flaps are affected.
The module remains active or inactive during engine startup based on whatever setting you used last. Hopefully that answers your question! I can't confirm exactly which flaps are affected.
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If you want just random noise, like any Infinti or Mustang ( sorry...I am euro..), then you can take out the electric actuators and block flaps.
But,
If you want the AMG sound, is very simple and no need to do anything.
On AMG within a very complex algorithm, the flaps are used for increasing the back-pressure squeezing the exhaust gases to compress inside the exhaust system - not too much of course - in such a way as the engine to start producing some calculated misfiring, knockoff, pop's&bangs, as when the system decide to open the flaps, the noise will come out together with the real noise from the engine.
So in my opinion, blocking/setting the flaps on open position, will consequently not making any backpressure, no calculated misfires, just pure cheap sound
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W213 All-terrain
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Spain has the best infrastructure in the EU but with only 120km/h speed limit, very close is Italy and Germany indeed has some troubles but they still ride over 200km/h where they can.
In the EU we have regulations and tariffs from ages, that's why we can build infrastructure, schools and hospitals, this is like normal here.
Even with more than 50% tariff for fuel ( all EU is like that), in Spain Diesel is between 1,24 and 1,45€ per liter ( lowest price in the EU) and considering long distance drive with 5 - 6l/100km that's completely irrelevant.
Of course, big gasoline engines is still present but more likely are "Sunday" cars
We was born with 10% tariffs for US cars, but nobody care as any US model is considered "exotic" so the one who wants to be exotic pays.
Spain is a very big country in Europe, very long distances between points of interest and bicycles can't be the near future. Maybe scooters like in Italy, but here even millionaires drive a Polo or a Ibiza on the way to the yacht port ...
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C63 amg esate
