E9x 335i N55 Exhaust Valve Operation Info

[realtrevor]

Hi All

Can someone give me some quick info on how does the exhaust valve on the 335i E9x N55 models operate.
I know on cold start the valve is closed by default, but after a short while it opens up when the revs have dropped.
My question are;

• Does is does it stay opened forever once the car is warm after a cold start?
• Does it open more at higher revs e.g 3000rpm?
• Does the Sport button (in DCT models) open up the valves just like the Fx models when you select Sport mode?

 

[corp]

I would actually like to know this too. Maybe underload it opens fully and when cruising/lower revs it closes a bit.

 

[realtrevor]

I would actually like to know this too. Maybe underload it opens fully and when cruising/lower revs it closes a bit.

Yes I'm interested in knowing the actual details on what RPMs does it open the valves.

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[gavsadler]

From what I know, the valve closes under partial throttle openings (to reduce noise / drone). I remember reading somewhere that on E-series cars it was <15% throttle openings.

I'm not sure how the modern gadgets like sport mode make a difference though.