I don't think this is the exhaust. What you describe is similar to what a few of us noticed to a significantly greater extent when we added M3 rear subframe bushings. One of the guys switched back to standard 3 series bushings and the noise diminished but is still noticeable. My guess is that you are noticing this noise that was there before but because you were listening to your car more you are now more aware of it. See this post
http://www.e90post.com/forums/showpo...5&postcount=32
in this thread
http://www.e90post.com/forums/showthread.php?t=532595.
I know the thread focuses on the fact that we all had Quaife LSDs installed but it has been determined it is not the LSD but the stiffer bushings that are making the noise you describe more pronounced.
Clearly there is an underlying issue...we would all like to know what it is.
Quote:
Originally Posted by jyeah
Hi All,
I was wondering if an exhaust drone for the OEM BMW Performance Exhaust on a 2010 335i with Auto Transmission is normal? It was dealer installed, too.
Symptoms compared to stock exhaust (after 3000 miles):
1. >90 dB loud idling (measured with a sound meter) on cold start (even my fiance remarked, "Your car sounds weird."), it does settle down after 2 minutes and sounds a lot quieter after that
2. Audible low frequency droning sound with slight throttle going uphill
3. Audible low frequency droning sound when cruising on highway around 70 MPH when engine is at ~2K-3K RPM with slight throttle applied. The moment I let the throttle go, the sound droning goes away.
Is this normal?
Because I got it originally because people on the forum mentioned there shouldn't be any drones, I am considering of putting my stock exhaust back on and selling the performance part because the droning tone is very annoying. Not like the pleasant note I get from putting down the throttle.
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