Quote:
Originally Posted by mblaucoupe135
I think it just makes it louder on startup. as for the sound of the exhaust in the different driving modes I think that is mainly controlled by the active sound. however I'm sure someone else on this forum may know more about this than I do.
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I was under the impression that the louder exhaust on cold starts on BMW turbo engines was the waste-gate bypassing the turbo to lite off the catalytic converter in order to reduce cold start emissions.