just got home from epic 24 hour adventure of picking up my new 550i. Flew from Boston to Wisconsin, arrived in Milwakuee at 8am, got back home at 5am this morning - basically 18 hours of driving- 1150 miles, hit some snow, etc. but she is now home. the car is mint - 2006 - 18k miles, prior to last night had never seen salt - unfortunately drove about 800 miles in heavy salt last night


my question is that when I started her up in cold wisconsin I noticed that exhaust only came out of the left tailpipe, but I figured that it would change after it warmed up because I remembered that my old 330ci had a vaccumm thing that would open one up the other side once it warmed up. half way home I noticed that dryed salt was caked on the left tailpipe and none on the right tip. I felt them and the left was hot and the right one was cold. same when we got home. it just seems like nothing ever came from the right tip. it is supposed to? I haven't looked under there yet ( it is 20 and there is snow on the ground, but is there a vaccuum thing that is supposed to open the right side?

any thoughts?

Love the car so far. fast.

Brian

If it is set up like the 545, the right tailpipe only opens up above approx 3,500 rpm. You should see a vacuum actuator on the right tip aft of the resonator. At highway cruise, you were not above the required rpm, thus the cold right pipe. You should be able to hear the right pipe open up at higher rpms due to the louder exhaust note. There is a definite change in tone, on mine anyway, when it opens up.

Congrats on the new ride. I know how you feel as I just picked up an 06 550i two weeks ago. Like yours mine is super clean with only 12k miles. I would get your car to the car wash ASAP and get the salt off as soon as possible. I have not noticed that the exhaust differences you mention above. Good luck with the car.

Right it only opens up under harder acceleration and higher rpms

Yep. +1.

I definitely notice an exhaust note difference at WOT and part throttle, even below 3500 RPM. This is on my 545

Awesome guys - thanks for the answers, makes sense now. I just thought that the second one stayed open once the car warmed up, but that isn't the case. I just washed the car and switched over to my winter wheel setup.

i'm going to guess, the flap is closed at low rpm, to increase low end torque.

I bet the flap is closed just to keep it quiet. Does anyone know if there is a flapper mod to be able to control the flap manually or electronically like you can do in the VW R32 and other cars with the flapper setup?