Evening all,
My mate owns a 330i Sport Touring and he recently asked me if I knew what the butterfly type valve was in one of his tail pipes. I don't know but I assume its to do with emissions. Anyway, he wants to modify his back box and wondered if removing this butterfly valve thing would affect performance etc...
Anyone on here own one or know about it?
Cheers
E46 back box question.
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Phatz
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The Sport - Gone to a new home to be slowly brought back to life
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stuartgallafant
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sounds silly, but im pretty sure its a noise thing only, so that dont get horrid resonance during idle?
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neilofla
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complete guess, but maybe it's a valve that opens at a certain point (e.g. full throttle or large throttle angles) to give louder exhaust noise, and perhaps is closed so it's quieter under smaller loads. Don't Ferrari and Audi have a system that opens up at 3k or 4k rpm to sound fruitier?
Or maybe it opens and closes to keeps back-pressure constant, but I don't know if back-pressure variance really matters that much in everyday engines.
Am I overthinking it?
Or maybe it opens and closes to keeps back-pressure constant, but I don't know if back-pressure variance really matters that much in everyday engines.
Am I overthinking it?