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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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well, you can disable the flap by unplugging the vacuum line, plugging it then tying it off. I'm pretty sure you won't make any power, though.
I think it may only close durring decel so I doubt there will really be that much of an effect on sound *outside* fo the vehicle. on the other hand, interior resonance will likely increase.
mine stays open at idle and every other 330 that I've been behind at a stop light had the valve open as well (lots of 330's in this area).
it's near the end of the tail pipe so it would be visible if it were closed.
nope, you have to leave it as is.

ChetG said:

Ive always been curious about the exhaust valve thing. I think the sound of the exhaust with holes open is too boomy and tiresome, not sporting in any way, just horribly boomy, and also creates significant resonance in the cabin which detracts from the engines smoothness. I was wondering if there was any way to remedy this (keep valve closed??), and not loose any power/torque. Does the mechanism work in any way to improve power, or is it purely for acoustic purposes.

thanks in advance.
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