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3.5is Exhaust Valve

Specific discussion about the E89 2009 Z4 (sDrive35is, sDrive35i, sDrive30i, sDrive23i)
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Burgy100
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3.5is Exhaust Valve

Post by Burgy100 » Thu Feb 14, 2019 3:11 pm

As I understand I believe the RH exhaust (looking from behind) has some sort of flappy valve inside it! I’m not sure that it’s working anymore and I don’t no which position it’s stuck in. Does anyone know how I can tell please and is there an easy fix for it please?

Steve
E89 Silver 3.5is 2015 with a Heated Steering Wheel :driving:

Chris1712
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3.5is Exhaust Valve

Post by Chris1712 » Fri Feb 15, 2019 11:51 am

Burgy100 wrote: Thu Feb 14, 2019 3:11 pm As I understand I believe the RH exhaust (looking from behind) has some sort of flappy valve inside it! I’m not sure that it’s working anymore and I don’t no which position it’s stuck in. Does anyone know how I can tell please and is there an easy fix for it please?

Steve
If you look straight down the exhaust you should be able to see it open or closed, you can probably hear whether it's open or not aswell?

It's literally just a disc that pivots in the middle to block off the exhaust. I've modded mine so it's permanently open, because noise :P .
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ihadablackdog
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3.5is Exhaust Valve

Post by ihadablackdog » Fri Feb 15, 2019 3:42 pm

So when should it open automatically, i.e. when starting the engine or caning it etc. My car sounds fruitier when starting from cold.

Is it just for sound, or does it perform some other function as well?
2011 E89 sDrive20i

Chris1712
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3.5is Exhaust Valve

Post by Chris1712 » Fri Feb 15, 2019 7:45 pm

It's open for like 2-3 seconds on start up, and then over certain rpms / throttle positions / gears when driving.
Pure Traction 35iS - Sold!
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Lazza
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3.5is Exhaust Valve

Post by Lazza » Sat Feb 16, 2019 12:38 pm

It’s sprung open. The vacuum mechanism closes it, so at startup it should sound meaty then slowly get quieter as it idles. It’s common to hear some rattling while the valve is actuating.
I’ve cut the vacuum tube on mine and reconnected it with a blank (small stud) so it’s always open.
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Burgy100
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3.5is Exhaust Valve

Post by Burgy100 » Sat Feb 16, 2019 5:24 pm

Thanks peeps for some very useful info and there’s me thinking it’s just an exhaust back box! I couldn’t of been more wrong!
E89 Silver 3.5is 2015 with a Heated Steering Wheel :driving:

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