[x328x]

I am about to pull the trigger on a custom exhaust. I might lose the electronic valve function .

What does this mean. What does this valve actually do

When we switch between sport eco etc does the valve do anything to make driving experience different

[jamoka3]

When I asked BMW for specifics of when the exhaust will be open, they said during cold starts, the left exhaust pipe will be closed for approximately 1 - 2 minutes. I was told they designed this for both noise-control reasons and vehicle warm-up. You will then here it open up and it will remain open.

However, while driving in Comfort or Eco Pro, it will adapt to driving habits. If you are not accelerating harshly, it will keep it closed most of the time to give off less sound. If you floor it though, it will open up. It will continue to open in close based on how much you are trying to accelerate.

When in Sport/Sport+ mode, the exhaust flap will remain completely open and the exhaust will start having more noise (the gurgling sound) whenever the engine RPM is decreasing. To hear what I'm talking about, roll down your windows and manually downshift to kick up your engine RPM to around 2500 - 3000 RPM and let the engine speed decrease. I usually hear it gurgle most if the RPM decreases near that range that.

Sport will also make the shifting 'grunt' noise more often in Sport mode. When accelerating hard, with the throttle past half way, manually shift around 4500 RPM and you will hear the noise I'm talking about. They didn't specify this but I believe the shifting noise is only with the Sport Auto.

Hope this helps..

[mahmoud samier65603]

good toke