640xi exhaust question ?

[lukej]

What’s the best and most economical way to get a little rumble out of the exhaust? It’s just to quit for me..

2015 640xi

[Tfzen]

Catless downpipe.

[upstate650]

Originally Posted by lukej

What’s the best and most economical way to get a little rumble out of the exhaust? It’s just to quit for me..

2015 640xi

easiest way is with an axle back exhaust. The stock cans on the 640 are really constricting. a free flowing exhaust will really open things up and let that sound out.

Might I humbly suggest: http://www.6post.com/forums/showthread.php?t=1482200

[Dsifer]

zip tie trick

[upstate650]

Originally Posted by dsifer91

zip tie trick

Only if it’s valved. Is the 640 exhaust valved?

[lukej]

Originally Posted by upstate650

easiest way is with an axle back exhaust. The stock cans on the 640 are really constricting. a free flowing exhaust will really open things up and let that sound out.

Might I humbly suggest: http://www.6post.com/forums/showthread.php?t=1482200

Ok thanks guys,,,

[lukej]

Originally Posted by upstate650

Only if it’s valved. Is the 640 exhaust valved?

I have no idea what your talking about?

Please explain.

[upstate650]

Originally Posted by lukej

I have no idea what your talking about?

Please explain.

Some bmw mufflers have two outlets on each muffler. Sometimes, one of those two outlets has a valve on it. That valve opens under rpms above 3K or so allowing exhaust gases out more easily and increasing sound output. The zip tie mod involved zip tying the valve open, so it increases volume at all times.

Obviously, this only works if your exhaust is valved.

Google "BMW zip tie mod" for tons of details and pictures.

I don't know if your car has a valved exhaust or not.

If you take some pictures of your mufflers from underneath, particularly where the pipes exit the muffler, we can easily tell you.

[lukej]

Originally Posted by upstate650

Some bmw mufflers have two outlets on each muffler. Sometimes, one of those two outlets has a valve on it. That valve opens under rpms above 3K or so allowing exhaust gases out more easily and increasing sound output. The zip tie mod involved zip tying the valve open, so it increases volume at all times.

Obviously, this only works if your exhaust is valved.

Google "BMW zip tie mod" for tons of details and pictures.

I don't know if your car has a valved exhaust or not.

If you take some pictures of your mufflers from underneath, particularly where the pipes exit the muffler, we can easily tell you.

OK perfect I’m out on a trip right now but as soon as I get back home I will look at it.

I really appreciate the explanation that helps a lot thanks so much .

[Margas]

No valves for the 640i.

I put m5 mufflers on mine with one of the valves open (having both open has unbearable drone - based on some threads on the f10 forum). It's a bit on the quiet side but is a definite improvement in sound and looks.