650i exhaust flaps kept open!!

[Gareth Steen]

I'm waiting on my new 650i M Sport Coupe to arrive (should be here in a week or so) and I ordered it in the new Sonic Speed Blue with black Nappa leather. Never saw this new blue before only on picture so I hope its as nice in real life as in the pictures. Anyway I have been watching videos on youtube on the exhaust sounds off the 650i and I must say they sound great, however in the initial startup it sounds very quiet until the driver gives it some revs. So I saw a video on youtube of a guy that has an M4 and he videoed how to make it sound louder at start up by unplugging this connecter thing that keeps the exhaust flap from closing. Just wondering is this gonna be possible to do on my 650i whenever I get it? Because the M4 sounded so much better after he unplugged the connecter thingy.

[bravo261]

It's easily possible, search for exhaust flap mod, its quickly done with a well placed zip tie so nothing permanent either

[AmooManiak]

Did you order the M package with the M exhaust? I gotta admit, the exhaust was the best surprise on this car! I previously had the 550i on which I installed the M5 exhaust with both flaps open. The car sounded good in the upper RPM range, however I didn't like the drone up until 2500K RPM. The problem is, everyone thinks you're racing them just because you're trying to get out of the non-drone area.

I love the ability to have a good exhaust that turns into a great exhaust when you get on it, but still keeps the luxury characteristics during cruising. I advise against opening the flaps if it's anything like the M5 exhaust.

[Gareth Steen]

Thanks guys with your feedback. As far as I know the 650i M Sport comes with a sports exhaust, whereas the non M Sport 650i does not. Ive ordered the M Sport. I think i'll try the zip ties and if I think there's too much off a drone all I have too do is cut the ties off again.... no harm done. Cheers guys.

[ndinh]

Originally Posted by Gareth Steen

Thanks guys with your feedback. As far as I know the 650i M Sport comes with a sports exhaust, whereas the non M Sport 650i does not. Ive ordered the M Sport. I think i'll try the zip ties and if I think there's too much off a drone all I have too do is cut the ties off again.... no harm done. Cheers guys.

One side open was the perfect balance for me. Both open gives an unbearable amount of drone and vibration.

Edit: misread the thread. This applies to M6 exhaust. Not sure about 650 stock exhaust.

[AmooManiak]

Here are a couple of clips of my stock M-sport exhaust from when I was dropping the car to get some mods done. Coming from a 550i with an M5 exhaust and open flaps, this gives me the perfect balance. Unfortunately the guy didn't put it in sport mode and just floored it after a roll.

[calbear550]

Originally Posted by AmooManiak

Here are a couple of clips of my stock M-sport exhaust from when I was dropping the car to get some mods done. Coming from a 550i with an M5 exhaust and open flaps, this gives me the perfect balance. Unfortunately the guy didn't put it in sport mode and just floored it after a roll.

Was it a competition M5 exhaust or non? I have my comp m5 exhaust from my 550i as well and was contemplating installing it over the msport exhaust on the 650i GC. I also was very surprised as to how nice the Msport exhaust is, but only problem is that I have to have it in Sport mode and Sport Shift to get it sounding the way I like it. Any info appreciated. Thanks.

[AmooManiak]

It was a non-competition. I'm not sure how much of a difference that makes. When the flaps were closed it was too quiet. With the flaps open, there was too much drone between 1500-2000 RPMS, which is where 80% of my driving occurred.

[BMPOWERED]

I have a 650i GC M sport and I must say the exhaust sound was a nice surprise on this car, having also come from a super quiet, stock 550i M sport. However, sometimes I felt like I had to work too hard (really get on it) to reap the benefits of the M sport exhaust. Therefore I tried the zip tie mod and now I think it's absolutely perfect! There is still zero drone at highway cruising speed. The only slight drone I notice (if you really consider this drone) is under light to medium acceleration from a stop, you can hear the low resonance of the exhaust. Once you get to cruising speed, it is quiet again. Best of all, the zip tie mod was free, took about 10 min, and if you don't like it, they can be cut off in a matter of seconds. My only problem now is that I am upgrading to an M6 style diffuser and will be going with M6 mufflers simply because I need the quad tips to match the diffuser.

[WhiteTornado]

I'm doing zip tie method for now until I upgrade to quad exhaust. The zip tie method really opens it up when you cold start it which I love but then quiets right down to idle. Idle is a more throaty sound and when I pull out into traffic quickly or spirited driving it sounds much better!

Just can't wait for a real exhaust

[SixPost]

Ive been trying to figure out if the exhaust valves are supposed to be open during cold start. From your experience, it sounds like you noticed that it was much louder cold starting with the flaps wired open, than it was in stock configuration... This would suggest that the valves are normally closed during a cold start.... would you agree???

Thanks

[JNMiller]

On mine, the exhaust flaps appear to remain closed on a cold startup. I have yet to hear the exhaust burbles at all, even in sport mode and in manual, and I am probably going to go ahead of and do the little unplug mod to see what it sounds like opened a bit.

[Flying Ace]

On the M cars, the flaps are closed on cold start. I did the mod, the only effects are cold starts. The valve is generally open on throttle applications, so you won't notice any difference in sounds most of the time.

Also, if you deactivate the ASD, it'll sound a bit better.

[Dsifer]

How do I do the zip tie mod

[Giggs11]

I wouldn't do it , as u get a slight deeper sound u will lose bit power in low rpm and when you step on it you will lose that gargle back pressure that valve creates , i did it and didn't like it at all ,