[sayemthree]

can anyone explain what this button does and how it works? it gives me 50 more HP right? (JK) but for real I am not sure and my owners manual is not around and its not on line yet either. google didn't help.

[DC X3M40i]

Originally Posted by sayemthree

can anyone explain what this button does and how it works? it gives me 50 more HP right? (JK) but for real I am not sure and my owners manual is not around and its not on line yet either. google didn't help.

for me it just seems to mute the fake exhaust noise that is piped into the cabin

[MrItaly]

I coded my fake noise off permanently at any setting and still notice a significant difference between the exhaust noise on or off. This comes from the servos activating between the resonator and tail pipes which vent exhaust gas and noise before they reach the pipes. It makes the car much louder from the outside and a noticeable difference from inside despite the excellent acoustic isolation.

[gatorfast]

I am wondering the same thing. In prior M cars, the exhaust valves were controlled by the engine mode (efficient/sport/sport+). Is that still the case with the X3M? If so, then is the exhaust button to permanently open/close the valves regardless of engine mode?

[Wills2]

Green light = more sporty sound, no green light = less sporty sound.

Pretty simple concept, switchable sports exhaust with added ASD.

[kaakti]

Fake means from the speakers?

[BMWZ4]

Originally Posted by kaakti

Fake means from the speakers?

Correct

[bennyboy77]

Originally Posted by BMWZ4

Correct

Originally Posted by BMWZ4

Correct

But do you need to put the engine in Sports mode to get the valves to open, irrespective of the 'fake' noise?

[BMWZ4]

Originally Posted by bennyboy77

But do you need to put the engine in Sports mode to get the valves to open, irrespective of the 'fake' noise?

My vehicle (all X3m's?) starts I default with Comfort, Comfort & Efficient. When I press the button, I hear a change. I haven't tried pressing the button in other settings because I have my 2 M buttons configured such that there is a change in the exhaust sound

[AJCC]

Are we talking about button that changes engine from efficient to sport and sport +?

[BMWZ4]

Originally Posted by AJCC

Are we talking about button that changes engine from efficient to sport and sport +?

No, the button that changes the exhaust note. It's the button just above the rear cam button

[Zero71]

Originally Posted by MrItaly

I coded my fake noise off permanently at any setting and still notice a significant difference between the exhaust noise on or off. This comes from the servos activating between the resonator and tail pipes which vent exhaust gas and noise before they reach the pipes. It makes the car much louder from the outside and a noticeable difference from inside despite the excellent acoustic isolation.

This is my experience also. It's definitely not just controlling the ASD.

[j080808]

Originally Posted by gatorfast

I am wondering the same thing. In prior M cars, the exhaust valves were controlled by the engine mode (efficient/sport/sport+). Is that still the case with the X3M? If so, then is the exhaust button to permanently open/close the valves regardless of engine mode?

https://x3.xbimmers.com/forums/showthread.php?t=1673454

[Max Well]

Originally Posted by AJCC

Are we talking about button that changes engine from efficient to sport and sport +?

Some images from the tech documents - difficult to fully understand what exactly happens when it is engaged, at least based on the rather vague information found in the manuals and documents. With our ASD units bypassed, even in Sport+, we're not noticing much difference inside whether it is off or on, regardless of speed or RPM. Granted we're not driving with our windows down so maybe the exterior noise is enhanced, but that isn't a concern for us. Would be helpful to know if it has any contribution to performance on the back end, though.

[gatorfast]

Originally Posted by j080808

https://x3.xbimmers.com/forums/showthread.php?t=1673454

What does that have to do with my question?

As another poster mentioned, even the manual is vague in its description of what the button does and how the exhaust sound changes by pushing the exhaust button compared to the engine response button.

[sayemthree]

Mine seems to always start with the green light on. So this is fake noise ? Any way to keep it off ?

[Zero71]

I've pulled fuse 218. I have no fake noise. In Sport and Sport plus there is a marked difference in external exhaust noise with the button on and off. I believe it's controlling the exhaust valves. An easy test is when you start the car up and the rear is close to garage, so the exhaust is easier to hear, toggling the button off makes the exhaust quieter. It's only going to impact sound if the valve is open, if it's closed then there'll be no difference, and if you've modded your valve to always be open then there'll be no difference either.

[AlpineWhite_SJ]

The function as I read it in the manual is to control the overall exhaust volume and tone to be sportier when enabled. That is achieved by opening the valves on the exhaust, which correspondingly gives you louder ASD sound from the speakers. if you disable ASD, you should just get the exhaust note with valves open.

For European models, the particle filters kill what little glorious noise there is left after all the cats, so not sure how much difference it makes.

[Wills2]

As far as I can ascertain with my ears, the ASD does change depending on the throttle mode selected, the sports exhaust is independent of that.

So from a base line of just the sports exhaust on, the ASD gets louder as you cycle up through the throttle modes but the sports exhaust operates separately from the throttle modes (clearly as it has a separate button)

[smithf80]

Originally Posted by Wills2

As far as I can ascertain with my ears, the ASD does change depending on the throttle mode selected, the sports exhaust is independent of that.

So from a base line of just the sports exhaust on, the ASD gets louder as you cycle up through the throttle modes but the sports exhaust operates separately from the throttle modes (clearly as it has a separate button)

This is incorrect.

Let me clarify this for everyone. The modes are what mainly control the exhaust flaps. There is a huge difference between Efficient and Sport Plus on my X3MC. The flaps are not fully open unless you are in Sport Plus.

From the S58 technical document:

The exhaust flaps are operated on a demand-oriented basis and can be influenced by setting the engine dynamics control buttons to “Efficient”, “Sport” or “Sport+”.

Apart from the engine dynamics control buttons, the position of the exhaust flaps can also be influenced by the sound button in the center console switch cluster.
In default mode the button is deactivated and the acoustic characteristics linked to the modes. If the Sound button is pressed then the vehicle interior acoustics are trimmed to the maximum comfort setting. That is independent of the selected driving mode – in other words the Sound button overrides other acoustics settings.

Thus, in order to obtain maximum comfort (quietness) when the Sound button is active, the exhaust flap is kept closed for as long as possible. Therefore, it no longer opens when the driver calls for more power but instead in response to the exhaust mass flow rate. It remains closed as long as it does not affect performance and fuel consumption or until the perceived noise level in the vehicle interior is more comfortable.

Activation of the Sound button also reduces all other activities that have an effect on the interior acoustics (ASD).

[Zero71]

Originally Posted by smithf80

From the S58 technical document:

Yet the owners manual contradicts that, stating opposite states of the button. When the Sound control button is switched OFF the sound is focussed on comfort. When it is switched on, the sound of the exhaust system takes on a more sporty nature. It also states that it has no affect on the exhaust system during engine warm up.

[smithf80]

Originally Posted by Zero71

Yet the owners manual contradicts that, stating opposite states of the button. When the Sound control button is switched OFF the sound is focussed on comfort. When it is switched on, the sound of the exhaust system takes on a more sporty nature. It also states that it has no affect on the exhaust system during engine warm up.

I can tell you with confidence from my ears that the Throttle Modes make 1000x more difference that the exhaust flap button.

The loudest I get the car is in Sport Plus, whether the exhaust button is activated or not.