M40i exhaust valve 🤔🤔🤔

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omegabri

Member
Hi all

Does anyone know the actual technical reason that the exhaust has a valve that only opens in sport mode etc. on the M40i?
I don't understand why a car would require a value in an exhaust system, which would effectively cause back pressure on the engine (when closed) compared to an open exhaust system.
Is it anything to do with the turbo, or engine warm up?

Can I have it switched permanently open? I'm guessing not only would the engine breathe better but it would sound more open.

Bri 👍🏻
 
The F Type and others have a similar system, having an open exhaust all the time can be very tiring on a long trip, it wakes the neighbours up, so pretty anti social. I had a mod exhaust on my last Z4, quite loud lots of crackles and pops but it was too much for me all the time.
The G29 in comfort mode is very docile and economic - 35mpg but pulls like a train from low revs, sport mode changes the whole car, throttle response, fueling, exhaust, take your pick which suits you
 
ive only got the 30i but ive got mine open all the time. its just a software thing. I bought bimmer code and bimmer link for my iphone. and the ob11 bluetooth device that goes with them. ill look later which one did the exhaust valve, but its an easy thing to do. you can also turn the fake engine noise off. still in 2 minds if I like it better on or off though.
 
Normally on BMWs the valve is open on cold start to allow the cats to warm up as fast as possible..

Like others have suggested closing it is to do with day to day comfort and possibly certain drive by tests..

Back pressure issues are irrelevant below say 200 BHP ..so not an issue for day to day driving..

And I’m sure they factored those in the design anyway..
 
I found a fuse that can be pulled and leaves it open. But decided to leave as factory anyway.
Mainly was wondering why and what for.
My mate has an M4 Comp. Now that sounds much better. Wish I could get the M40i to sound like the M4 Comp 🤔 Oh well.....
 
christy said:
The M40i exhaust valve plays a crucial role in optimizing performance and sound in high-performance vehicles tyre shops in kakkanad It regulates exhaust flow, enhancing engine efficiency and improving the driving experience. By controlling the exhaust sound levels, it balances between a quieter ride and a sporty exhaust note. Proper maintenance or upgrades to the exhaust valve can significantly impact vehicle performance and overall driving pleasure.
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Love this new generation of BOTS..or is it a little chappy in Banglalore tapping away?
 
omegabri said:
I found a fuse that can be pulled and leaves it open.
Click to expand...
Which fuse please? :thumbsup:
I use BimmerLink to make it open but I need to connect my phone to the OBD dongle everytime I want it constantly open.
 
Trying to remember...... F203. Its located on the left hand side of the fuse terminal board, in the boot. It's a 7.5 amp. In fact, I think the only 7.5 in that block (which if memory serves me correctly is the red one.)
If you drive the car, and come back with the exhaust hot and in sports mode, it should be in the open position. Turn the ignition off, and pull the fuse. Done! The car doesn't come up with any faults or anything, which is kinda why I was wondering what exactly the flap was for? It certainly doesn't seem to effect driving modes.
Anyway, with the fuse out it stays open 👍🏻👍🏻 I tried it, but didn't understand why the flap is there and what's its for, so I just popped the fuse back in
 
Ledg said:
ive only got the 30i but ive got mine open all the time. its just a software thing. I bought bimmer code and bimmer link for my iphone. and the ob11 bluetooth device that goes with them. ill look later which one did the exhaust valve, but its an easy thing to do. you can also turn the fake engine noise off. still in 2 minds if I like it better on or off though.
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I’ve got bimmer code. Would love to code the valve to always be open. How did you do it?
 
ori said:
Ledg said:
ive only got the 30i but ive got mine open all the time. its just a software thing. I bought bimmer code and bimmer link for my iphone. and the ob11 bluetooth device that goes with them. ill look later which one did the exhaust valve, but its an easy thing to do. you can also turn the fake engine noise off. still in 2 minds if I like it better on or off though.
Click to expand...

I’ve got bimmer code. Would love to code the valve to always be open. How did you do it?
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Fake engine sound can be turned off by bimmercode easily. All you need to do is backup and remove the FSC code from RAM module.

But for exhaust valve, you can't code it to always open using bimmercode. You will need to use bimmerlink to force it open and you need to do this every time. This is my understanding.
 
ori said:
Ledg said:
ive only got the 30i but ive got mine open all the time. its just a software thing. I bought bimmer code and bimmer link for my iphone. and the ob11 bluetooth device that goes with them. ill look later which one did the exhaust valve, but its an easy thing to do. you can also turn the fake engine noise off. still in 2 minds if I like it better on or off though.
Click to expand...

I’ve got bimmer code. Would love to code the valve to always be open. How did you do it?
Click to expand...

sorry not looked on here for a while, bummer link is what I use to do the exhaust valve.
 
I’ve had the fuse out a few times for the exhaust valve, and not found it drones on the motorway. However, I've reinstalled it. Setting Sport Individual with comfort transmission, I’m finding pushing the accelerator hard but then releasing fairly quickly does occasionally get pops and burbles which is enjoyable - a 2020 car. Ironically, going really slowly and letting the engine braking do the work, it burbles quite a bit, and accelerating just a little and backing off slowing right down it does the noise thing again.
 
I don’t like the ASD, specifically with an additional amp installed; the engine sound from the speakers wil become horrible.
At first I switched off the ASD using bimmercode, including the removal of the FSC code. However this also prevented software updates to install because of the missing FSC code in the modules.
Also this disabling of ASD didn’t do anything for the engine/exhaust sound, which I really like in sports mode.
Searching the web I found a post regarding an “engine sound” option in the i-drive menu and decided to give it a try.
It seems to work for our G29 (at least for the M40i) and gives you a menu to alter the real engine/exhaust sound for the different driving modes.
You can enable this i-drive menu option using bimmercode; go to Headunit, Expert and set DISPLAY_MENU_CONFIGURATION_ENGINE_SOUND to enabled and DISPLAY_CONFIGURABILITY_ENGINE_SOUND to aktiv
Play around with the options the menu gives you; it’s clear setting the mode to sporty enhances the engine/exhaust sound in normal and economy modes as well.
The selected mode does not stick when switching off the engine but the menu itself is programmable to one of the numbered buttons of the audio system. Imho easier than using bimmercode to open the exhaust valve every time you start your car and also good to have the option for more “silent” modes when cruising on a highway.
I don’t know how or if it also affects ASD because I don’t use that signal currently in my additional amp anymore (instead of coding it out to prevent future software update errors) but that’s an other topic and still work in progress for me.
 
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