[Capital10]

I have a 2018 540i Msport, I was wanting to modify the exhaust flap to always stay open, partly for sound but mainly because I hate the look of exhaust only coming from one pipe at idle.

So I’ve gotten under the bumper to look at it, I am not able to move the flap when the car is shut off. I’ve even tried pushing a plastic trim tool in there to manually open it. It will not open with any reasonable amount of force.

Putting it in sport plus even warmed up doesn’t open it. I took it on a quick spirited drive in sport plus and then got out to check in the driveway and it was still closed.

I also tried removing the fuse for the flap but it didn’t work because the flap would never open in any test I did.

Has anyone done the mod on their G30 or know how to make the valve open manually so I can check to see if mine is malfunctining.

Any info would be appreciated

Thanks

[Shepway]

It only opens when driving at about half throttle, and as it's still connected to its actuator you won't be out manually push open, take the small connecting spring clip out and it will easily open but then you have to form something to keep it open, are used an old kebab skewer and a pair pliers took me five minutes.

[DBO]

^I've done the same thing, although it doesn't really change the sound profile. Have you guys noticed that on startup the car seems a lot throatier and louder before it settles back down to being almost silent? There must be something active in the exhaust system somewhere to cause that but I haven't found it yet. There's no other physical linkages in the rear silencer so I could either be something internal (i.e. passive) or further upstream.

[tonyhhandler]

Originally Posted by DBO

^I've done the same thing, although it doesn't really change the sound profile. Have you guys noticed that on startup the car seems a lot throatier and louder before it settles back down to being almost silent? There must be something active in the exhaust system somewhere to cause that but I haven't found it yet. There's no other physical linkages in the rear silencer so I could either be something internal (i.e. passive) or further upstream.

It's a warm up phase mode to quickly heat up the catalytic converter, there is no physical change but it's a software in the DME.