2016 640i (F06) Gran Coupe - Cannot Hear Exhaust After Engaging Sport Mode

[eou2]

Hi all,

Been trying to find information on this issue I've recently started having, wondering if anyone has experienced this before I bite the bullet and bring it to the shop for a look. Some background:

- In the past when I engage Sport Mode the exhaust profile would change, exhaust would be louder, letting off the gas would result in pop/crackling of the exhaust, and under hard acceleration you could hear a nice pronounced "BRRAP" between upshifts

- Looks like the only 6-series with Active Sound in this model generation is the diesel version, so the exhaust sound should be purely mechanical (exhaust flap open/close) and no Active Sound in the gas models (N55)

- Recently I've noticed that when I engage Sport mode, the dials would all change to the red Sport mode dials as before, gear changes would follow the Sport profile (higher revs before upshifting), but the exhaust sounds exactly the same as it is in Comfort mode when I'm in the car (no pop/crackling on deceleration, no BRRAP on upshift, generally no difference in exhaust sound between Comfort and Sport)

- Listening to the exhaust when standing outside the car it sounds just like it would during Comfort mode, no difference when changing to Sport or Sport+

Has this happened to any fellow Bimmerpost members? Any feedback would be appreciated!

[scubachris]

hi.
my car is a 640d,but i believe some of the petrol 6 series have a pneumatically or servo motor controlled flap inside the exhaust tail pipe..not sure if its the twin exhaust (like yours) or the quad exhaust..
this flap opens both tail pipes for cols start and sports mode..some people even tye wrap them open sp they sound louder all the time...it is possible that the flap.or control system for the flap has seized up or not functioning propperly and the flap is staying shut,
that would be my guess,,also have you had any software updates lately? there might have been some coding regarding the exhaust that has been wiped.

[arucano]

According to the parts listing on REALOEM, the 640 does not have exhaust flaps, to reroute the exhaust (and get a change in noise level)

[eou2]

Thanks scubachris and arucano for the responses! I've got an LCI model based on my build date so when I checked the VIN my model does have the exhaust flap on the right muffler, I have to assume it's stuck just like you mentioned so will probably need a repair. Didn't know it would make that big of a difference in the sound!

[Luftpost]

Take a look inside your exhaust pipe. Very easy to determine if you have the exhaust flap or not. While it is vacuum operated, you can actuate it manually (if you have one) with a long probe. Photo below is just a stock bmw photo, not from 6 series.



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