Quote:
Originally Posted by wichitagreg
Does the 2016 M235i (F23) exhaust have a valve that give it the dual outlet in Sport and sport + mode?
I cannot find anything in my owners manual.
It is stock as far as I can tell.
Greg
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For M235i stock exhaust, that is an anti drone valve. I know other bmw models use this setup too, and not sure if it's identical on the Mperf muffler. It closes in certain situations to prevent excess cabin NVH when the engine speed drops below 1500rpm-ish, I'm guessing because the ZF8 in D constantly wants to be between 1100-1500. Others have reported it being open as well as shut in different modes, as well as open and shut sometimes on startup. Seemed inconclusive, but none of that info really concerns me because the idea of a PCM controlled valve is sacrilege to me. FWIW, there's not much increase in drone with it open in all driving situations. Most noticeable on cold start, for a brief 10-15 seconds
I removed the spring that connects motor to valve, then ended up tack welding the valve in the open position. I tried JB weld a couple times at first, but it vibrated loose each time and made a racket. I welded it in a way where I can break it off later and return to normal function if needed.