Easy way of opening exhaust valve on a 550i
 

The solenoid is behind the cover of the let tail light. Very easy to get to! All you need is a large syringe and a hose clamp used in Aquarians to regulate air flow on the air pumps. You pull the side pipe off the solenoid push it onto the syringe and draw it back, you will hear the valve open, put the clamp on the hose, push it back on the solenoid. Job done! Check the exhaust valve to make sure it is fully open. That's it. I am sure this can be done to any BMW with a valve on the exhaust.

What do you gain from doing this?

I wouldn't recommend it on an I6- I've had a master tech tell me that it serves a warm-up and backpressure function (at lower RPMs) on them. Doesn't matter on a V8, so if you want to safety wire it open or use this nifty vacuum technique, have at it. It will make your V8 car actually sound like a V8 at idle.

Noise. :rolleyes:

It is a V8..... and yes that is what I am going for....just a little more noise. I have looked at 650 exhausts and they seem to have no valves on there two boxes? The two cars share the same engine so, I can only conclude the valve only service to keep the car quite at low speed and idle? I tried a new rear exhaust, but that was just too loud. The seems just right!

On the V8 it's definitely a rumble-reducer at idle- beware, though- make sure that it actually opens when you goose the throttle well- Mine was stuck when I bought the car- the dealer ended up replacing some relay and the actual solinoid before I bought it.

How do you check for this?

I'm not certain of the exact throttle / load percentage required, but it should have some movement revved smoothly to 3/4 throttle at idle, and less in drive with a load. Mine just never moved (I could tell by the soot on one pipe but not the other, and condensation on one pipe after a spirited drive, but not the other).

I have a nice "rumble" now at idle and at low speed.... I think this is the way this car should have been straight from the factory.... one of the reasons you buy a V8 is for the "sound", God knows its not for the fuel economy!

Did you try any physical restraints on the arm, e.g. safety wire or hangar stuff? My only concern would be that the vacuum leaks out past the clamp eventually...

ahh this is a complicated process. All you need to do is bypass the vacuum valve in the trunk as the poster indicates where it is.

The vacuum valve turns on above 3,000 RPM ( electrically). The vacuum is always there from the vacuum line. This means if you disconnect both vacuum lines, one from engine, 1 to exhaust valve, you have a constant vacuum to keep the exhaust muffler valve open.


As long as you have no vacuum leaks this keeps the secondary valve and muffler seconf pipe open, giving you a more rumble at idle and free flowing exhaust. I have picked up .5 mpg by doing.

Does a later model 550 with the sport package have this valve? I was just under my car looking at the muffler in the back, and I don't see anything but a single pipe splitting into two, entering two separate mufflers, then exiting into individual tailpipes. I don't see any kind of valve mechanism under there. It also seems as though both tailpipes are exhausting at idle. I believe that the sport package included a different exhaust on the 550 in 2008. Could it be that this feature doesn't exist with the sport package?

Keith

Nice- I'll grab a connector and give it a try.

This sounds good! have you checked the valve at idle? was it open?

Any pictures?

Yes - Valve opens on vehicle start and stays open.

this^

What?

Thank! going to try this.

Where the heck is the solenoid? I don't see it

x2 on this.. i have an 08 w/ M-sport package. I havent looked into the exhaust but it does have a nice purr when you turn it on and it goes quiet right after.

Would like to keep the purr going :)

Exactly my thought! haha you beat me to it.

I joined the two pipes, and it work great!:thumbup: Valve opens when the car is started and stays open. You can hear the car at low speed now. I have not notices any bad side effects of doing this at all amd mine has been this way for three weeks now. Fuel consumtion is still the same, so all looks well.

Would this work on a 545i?

I can not see why not.... look for the solinoid in the boot join the pipes and see.... best tip I have found on here so far:thumbup: