Strange deep rhythmic pulsing noise ar 2250 RPM in 7th gear

[noone]

Picked up a new 2018 M3 competition with 500 miles on it with MPE all stock from the factory. Drove it home 800 miles. On the drive home, I noticed while driving 80 mph with cruise on in 7th gear at 2250 rpms, a strange deep noise wondering if it's the exhaust. Goes like this- hummmmmmmmmmmmmmm, pause, hummmmmmmmmmmmmmmm, pause etc. it's a weird pulsing rhtymic noise and deep like it's possibly exhaust related but I can't really tell. If I drop the car into 6th gear, and drop my speed so it gets to 2250 rpms, the sound is not reproducible. Wondering if anyone experienced this and what was done to address. Thanks.

[millerrh]

Possibly some kind of drone from the exhaust. I have only had mine a week and while driving along the highway today, thought I noticed a tad bit of drone as well. Didn't really bother me much (not that noticeable) and I didn't pay attention to the RPM or anything like that when it happened. I have had aftermarket exhausts on most of my previous vehicles and exhaust drone is a real thing. What I heard isn't even comparable to most aftermarket exhausts.

[knightarmor]

Sounds like you are describing the Active Sound (ASD) being pumped through the speakers. Disable this and let us know if it goes away.

[noone]

Originally Posted by millerrh

Possibly some kind of drone from the exhaust. I have only had mine a week and while driving along the highway today, thought I noticed a tad bit of drone as well. Didn't really bother me much (not that noticeable) and I didn't pay attention to the RPM or anything like that when it happened. I have had aftermarket exhausts on most of my previous vehicles and exhaust drone is a real thing. What I heard isn't even comparable to most aftermarket exhausts.

Is exhaust drone usually consistent, like one long hummmmmmmmmmm ?

Because mine sounds like you are in a spaceship- hummmmmmmmmmm hummmmmmmmmmm hummmmmmmmmmmm

[millerrh]

Originally Posted by noone

Is exhaust drone usually consistent, like one long hummmmmmmmmmm ?

Because mine sounds like you are in a spaceship- hummmmmmmmmmm hummmmmmmmmmm hummmmmmmmmmmm

In my experience with non BMWs, exhaust drone has more likely been a pulsating type sound that is not consistent, but also has a consistent presence as well. So you will hear a pulsating hum with drone that isn't' just a consistent sound. My theory is that the drone comes from some resonant frequency in the cabin. So as you hover around that frequency it will fade in and out giving you that pulsating sound.

[noone]

Originally Posted by millerrh

In my experience with non BMWs, exhaust drone has more likely been a pulsating type sound that is not consistent, but also has a consistent presence as well. So you will hear a pulsating hum with drone that isn't' just a consistent sound. My theory is that the drone comes from some resonant frequency in the cabin. So as you hover around that frequency it will fade in and out giving you that pulsating sound.

Thanks for this input. It's probably not worth worrying too much about as I wouldn't think the dealer could do much if anything about it.

[NaptownBimmer]

Sorry to resurrect an old post, but I am experiencing the exact same issue in my new to me 2016 M3 non-competition with 56k miles. OP, did you ever find out what was causing this rhythmic humming noise or have you just learned to live with it?

[noone]

I don’t drive 80 much consistently in this car so I don’t really know. I’ll check again tomorrow. Mine is not a daily driver. I’ve got less than 15k on the odometer.

[Doctor X]

Post an audio clip.

Will be hard to understand the sound from typed out messages hahah