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      01-04-2015, 01:40 PM   #7
kd0t
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Drives: M235i
Join Date: Oct 2014
Location: SoCal

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Quote:
Originally Posted by ehagerty
So instead of starting a new thread for this question I will tack onto the OP because it is similar.

I installed the MPE and when at start up the flap is closed the exhaust is very loud. At 5am in the morning in the garage on a work day it really resonates. I was thinking about doing the mod so it is open all the time and it would be quieter at start up but not sure what the negative effects would be and why it exactly exists in the first place. Is it to help CAT warm up and/or the get the EGT's up quicker? I would have thought when you upgrade to a M performance exhaust this would be one of the items they would do away with so I figured there was a legitimate reason.

Sorry for all the wind.....thanks
I've heard it's only open on one exhaust during cold start to help warm up faster.

I'm not sure if doing the exhaust flap mod would make it quieter though.. I could be wrong but my brother said it's actually louder inside the house when I cold start my car.

What you can try to do is maybe back up to the driveway after you start it? And let it warm up there - so the sound doesn't get amplified in the garage
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