Thread: exhaust valve
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      05-26-2011, 09:40 AM   #8
doughboy
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Drives: 2018 M2 Comp 6MT
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Quote:
Originally Posted by m1bjr View Post
Not even at cruise.

Only during cold enrichment cycle.

You should hear it pop open once its off warm-up.
it doesnt close again unless its subzero.

You'll see easily from the vapour on a cold morning, that both are open quickly.
It does open after the fast cold idle, but it's used by the DME again on light throttle cruise and at other specified load/throttle points to control noise.

I tried disconnecting mine so it stayed open, it sounds loud at warm up but the boominess at about 80 on light throttle is horrendous. There is increased boom noise at other times too.

Saves BMW having to design a perfect exhaust, just use a flap to get rid of unwanted resonance.

Last edited by doughboy; 05-26-2011 at 09:47 AM..
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