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      02-02-2017, 01:37 PM   #170
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Drives: F90 M5
Join Date: Sep 2009
Location: SoCal

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Quote:
Originally Posted by cbakking View Post
I have same question about the valve control on stock exhaust, I even took it to dealer about it.
As my X5M inner valve doesn’t open when M button is pressed, SA and shop foreman told me that it doesn’t work that way.
They told me that it never opens instantly when M button is pressed, it’s actually controlled by the back pressure.
Is this true? Anyone here with stock X5M exhaust that valve opens instantly when M button is pressed?
False. Well, sorta true, but mostly false. The valves will open up automatically at certain RPMs when not in M mode, but will open and stay open as soon as you hit the M mode button.
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