3.5i exhaust pipes

[jtaristi]

I have noticed that from one of the exhaust pipes there is hardly no smoke coming out and it does not get hot. The other one gets normal amount of smoke out and gets warm (drivers side).
Is this normal?. Is one of them fake, or only works under certain conditions?
Thanks.

[Deda]

it is not fake,that is for sure!

[Anteater]

The reason is that there is a vacuum flap on the right-hand tail pipe which is electronically closed below 2500 RPM to better control exhaust gas flow and noise. This forces all the exhaust gas through the left-hand tail pipe until the revs rise and the valve opens. A pretty common BMW feature.

Cheers, Anteater

[jtaristi]

Originally Posted by Anteater

The reason is that there is a vacuum flap on the right-hand tail pipe which is electronically closed below 2500 RPM to better control exhaust gas flow and noise. This forces all the exhaust gas through the left-hand tail pipe until the revs rise and the valve opens. A pretty common BMW feature.

Cheers, Anteater

Thank you very much. Makes sense.

[xDrive50i]

Originally Posted by Anteater

The reason is that there is a vacuum flap on the right-hand tail pipe which is electronically closed below 2500 RPM to better control exhaust gas flow and noise. This forces all the exhaust gas through the left-hand tail pipe until the revs rise and the valve opens. A pretty common BMW feature.

Cheers, Anteater

I don't think that either the 30d, 35d or 35i have this feature. Now the 50i on the other hand does, however it has this feature on both the driver and passenger side for the second exhaust pipe (each side has two exhaust pipes that lead into the exhaust tip finisher). See below:

30d, 35d and 35i exhaust system:

Attachment 174192

50i exhaust system:

Attachment 174193

[Anteater]

Originally Posted by xDrive50i

I don't think that either the 30d, 35d or 35i have this feature. Now the 50i on the other hand does, however it has this feature on both the driver and passenger side for the second exhaust pipe (each side has two exhaust pipes that lead into the exhaust tip finisher). See below:

30d, 35d and 35i exhaust system:

Attachment 174192

50i exhaust system:

Attachment 174193

Actually, that is the rear exhaust system just for the diesel - the 35i does have the vacuum flap - and is a different system to that which your links shows - see picture attached. The item #10 shown relates to the exhaust flap.

Cheers, Anteater

[CyberDude]

Maybe someone at the factory forget to remove the paperwork from inside the exhaust pipe. Just kidding! LOL

http://www.bmwusfactory.com/uploaded...anu17_high.jpg

[xDrive50i]

Originally Posted by Anteater

Actually, that is the rear exhaust system just for the diesel - the 35i does have the vacuum flap - and is a different system to that which your links shows - see picture attached. The item #10 shown relates to the exhaust flap.

Cheers, Anteater

I stand corrected. Thanks Anteater.

I think I must have clicked on 35d (twice in a row) instead of 35i when I was comparing the different exhaust systems.

So to sum this up:

30d - No Exhaust Flap on either Driver or Passenger side
35d - No Exhaust Flap on either Driver or Passenger side
35i - Passenger side DOES have an Exhaust Flap, Driver side does NOT
50i - Passenger side AND Driver side have Exhaust Flaps on the inner most pipes the outer ones do NOT (50i has two exhaust pipes her exhaust tip finisher/tail pipe)

Again, thanks Anteater for pointing this out!