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only difference with OEM "sports muffler" is cosmetic

1403 Views 11 Replies 4 Participants Last post by  31st330i

I finally got an answer to this thanks to my local parts manager who called BMW (and I suppose spoke with the district parts manager or a deligate).

apparently the sports muffler has black tips and costs $5 more - that's it.

Fred Meloan did tell me (after checking with his parts guy) that all US cars already have the sports muffler but this didn't jive with me since the ETK showed that there were two additional parts required, a vacuum plug and a tie strap.

so now we know.

oh well, at least the OEM muffler is already a straight through design.

okay, so now I'm thinking about removing the resonator or replacing it with the supersprint straight through resonator.
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If the Bentley Manual is correct, the valve is closed only at idle for noise reduction. If you have a friend slowly bring the revs up from idle, you should see the flap open.
I just read in this month's Automotive Engineering that the new 7 has the same flap arrangement in one pipe that is closed up to appro 2200 RPM. How can you tell the guy in front's flap is open - by the vapor coming out of both pipes? Maybe the flap doesn't close completly.
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