SL/R231: DOES the facelift SL450 have an exhaust flap???
Thread Starter
MBWorld Fanatic!
Joined: Oct 2010
Posts: 8,120
Likes: 4,351
From: Corona Del Mar, CA
2019 SL450, 2019 E450 Luxury Trim Wagon, 2024 BMW I7 xDrive60
DOES the facelift SL450 have an exhaust flap???
We touched on this in another thread, but it went unanswered, so I thought would start a new thread.
Under hard acceleration, my 2019 SL450 ROARS. At all other times, it is very quiet, which leads me to believe that when you really open the throttle, an “exhaust flap” opens up. Does anyone here know for sure? Might someone have a diagram showing the exhaust system? If it were a simple thing to do—and would not cause any harm—I would consider disabling such a device, as I prefer my vehicles to be as quiet as possible.
Under hard acceleration, my 2019 SL450 ROARS. At all other times, it is very quiet, which leads me to believe that when you really open the throttle, an “exhaust flap” opens up. Does anyone here know for sure? Might someone have a diagram showing the exhaust system? If it were a simple thing to do—and would not cause any harm—I would consider disabling such a device, as I prefer my vehicles to be as quiet as possible.
Senior Member
Joined: Oct 2019
Posts: 293
Likes: 153
From: Nova Scotia, Canada
2019 SL450; 2023 M850i coupe
Not sure about a flap, but as I think you know (from attached link) the 450 has an Active Exhaust Sound Booster in the trunk. As you suggested in that link: “it might be easy to just unplug the thing, to see what the effect is?”.
https://mbworld.org/forums/sl-class-...generator.html
Have you tried unpluging the thing?
https://mbworld.org/forums/sl-class-...generator.html
Have you tried unpluging the thing?
Last edited by hornethandler; May 3, 2026 at 02:52 PM.
Junior Member
Joined: Dec 2025
Posts: 19
Likes: 4
2011 R350, 2025 GLA, 2018 SL450
as a new owner of a facelift '18 450 and a avid tinkerer that has a penchant of playing with automotive systems my strong suspicion is the extra noise is from the exhaust trunk speaker. startup and the burble on throttle lift sounds exactly the same every time.not a stretch that it may be active while driving in sport also.
Playing with the trunk speaker is on the short list but won't happen till the following week
Playing with the trunk speaker is on the short list but won't happen till the following week
