[harperium]

Has anyone noticed this?

I have Fuse 203 pulled (exhaust valve always opened).

What I've noticed is:

1. The pops and bangs always come from the right (passenger) side
2. A lot more moisture comes out of the left (driver) side
3. With Fuse 203 pulled, not only is cold start twice as loud (at least), the are more noxious fumes esp. from the left (driver) side, e.g. ammonia smell during warmup.

I would guess the exhaust path between the 2 sides is not the same?

[Blacktemplar]

I’ve noticed that as well - after a longer drive in Sport the left side exhaust is almost cold, while the right side is hot. There’s also a lot less condensation/exhaust fumes from the left, which makes me think there’s not much functionality on the left channel. Either that or the valve isn’t opening properly on mine.... don’t have fuse 203 pulled

[harperium]

Originally Posted by Blacktemplar

I’ve noticed that as well - after a longer drive in Sport the left side exhaust is almost cold, while the right side is hot. There’s also a lot less condensation/exhaust fumes from the left, which makes me think there’s not much functionality on the left channel. Either that or the valve isn’t opening properly on mine.... don’t have fuse 203 pulled

Even in Sport, the valve won't open unless you're above around 4000 RPM

Hence the desire to pull Fuse 203.

Most of the sound you hear from the exhaust is ASD when the valve is closed. Welcome to The Matrix.

[Blacktemplar]

Originally Posted by harperium

Even in Sport, the valve won't open unless you're above around 4000 RPM

Hence the desire to pull Fuse 203.

Most of the sound you hear from the exhaust is ASD when the valve is closed. Welcome to The Matrix.

So rev the engine to > 4,000 rpm then pull 203?

[harperium]

Originally Posted by Blacktemplar

So rev the engine to > 4,000 rpm then pull 203?

Let the car warm up, put it in Sport, rev it up some, turn off car (from Sport mode), pull the fuse. This seems to leave the fuse in an open state.

You can easily tell b/c exhaust will come out of the left tip idling, in any mode.

From what I can tell, if Fuse 203 isn't pulled, when you're in Sport mode, the valve doesn't fully open esp at lower speeds and RPMs. How this relates to pulling the fuse I don't know. I've only pulled the fuse while the car was off.

Even at a dealership - they had to put in the fuse in order to perform the backup camera recall, and then they re-pulled the fuse. I'm fairly certain the dealership didn't have the car in Sport mode or anything, but the valve is open all the time. Others have reported you have to be more careful with the timing and the procedure to get the valve to stay open but that wasn't my experience.

[chicagofan00]

Originally Posted by harperium

Let the car warm up, put it in Sport, rev it up some, turn off car (from Sport mode), pull the fuse. This seems to leave the fuse in an open state.

You can easily tell b/c exhaust will come out of the left tip idling, in any mode.

From what I can tell, if Fuse 203 isn't pulled, when you're in Sport mode, the valve doesn't fully open esp at lower speeds and RPMs. How this relates to pulling the fuse I don't know. I've only pulled the fuse while the car was off.

Even at a dealership - they had to put in the fuse in order to perform the backup camera recall, and then they re-pulled the fuse. I'm fairly certain the dealership didn't have the car in Sport mode or anything, but the valve is open all the time. Others have reported you have to be more careful with the timing and the procedure to get the valve to stay open but that wasn't my experience.

Fuse 203 doesn't need to be in place to do the software updates. Fuse 218 (for ASD) does need to be in for the software updates to work.

[BMWZ4]

I'm interested in doing this but this is the 3rd how-to variation I've read. Is there an actual step-by- step available? I searched, but no firm instructions

EDIT: ok nvm...I missed this post. Seems it's the way to go
https://www.bimmerpost.com/forums/sh....php?t=1692504

[patrickkc]

I want to pull fuse 203 too, but my dashcam was wired up to fuse 203. Does somebody know where I can relocate the dashcam fuse from 203? I believe fuse 203 is always live.

[tonyb15re]

Maybe Im missing something, surely the valve is electronically opened thus pulling the fuse would stop it from opening as you're stopping the lectric from getting through? I would have also thought that the valve routes gasses through both sides of the exhaust thus silencer (muffler for the people over the pond) therefore quieter, if its open then gasses would route out without going via the muffler therefore only one side with the clean less silenced path would be used.

[SteveX3M40i]

Originally Posted by tonyb15re

Maybe Im missing something, surely the valve is electronically opened thus pulling the fuse would stop it from opening as you're stopping the lectric from getting through? I would have also thought that the valve routes gasses through both sides of the exhaust thus silencer (muffler for the people over the pond) therefore quieter, if its open then gasses would route out without going via the muffler therefore only one side with the clean less silenced path would be used.

Hi,
I am sure that I remember reading the the valve actuator is spring loaded and that it needs power to keep it closed - therefore removing fuse 203 whilst the valve is in the open position - would ensure that it stayed open!
Cheers
Steve

[Alias1431]

Source?

[satz]

Does the left side exhaust valve need to be closed for some reason (by design)? Does it help with warming the engine faster, or reducing emissions while engine's cold?

Or would the exhaust cause a drone if you force the valve to be open all the time?

Is there any mechanical way of trapping the valve open? I remember on the E90 335i, there were a couple of mods involving the vacuum activator line for the valve...

[Blacktemplar]

Originally Posted by harperium

Has anyone noticed this?

I have Fuse 203 pulled (exhaust valve always opened).

What I've noticed is:

1. The pops and bangs always come from the right (passenger) side
2. A lot more moisture comes out of the left (driver) side
3. With Fuse 203 pulled, not only is cold start twice as loud (at least), the are more noxious fumes esp. from the left (driver) side, e.g. ammonia smell during warmup.

I would guess the exhaust path between the 2 sides is not the same?

Update - now running with 203 pulled, and I've noticed the same thing, much more vapour from the left side exhaust, and when I stop, the vapour takes longer to clear from the left. Haven't noticed anything obvious re pops/bangs or smells, but cold start is louder and as far as I can tell more of the noise comes from the left. I've also noticed that after a longer run, the right hand tailpipe is hotter than the left.

[suby01]