cyberay

Anyone know of a way to either adapt the exhaust flap profile of the sport setting to the efficiency setting? Or better yet, a way to keep the flaps open regardless of engine speed. On other I cars that I have owned, or own, the flaps open when vacuum is not present. On this S550 coupe I've found it is just the opposite, the flaps are pulled open when vacuum is applied to a vacuum motor located on one of the two exhaust pipes on each side just ahead of the tip. Originally I thought that I'd locate the fuse that controls the function and remove it to deny vacuum to the motors. But then I found that would just keep them from opening under any condition, plus there doesn't appear to be a fuse dedicated to just that function, unlike the S63 AMG which does. There is one other possible solution and that is to disconnect the linkage between the vacuum motor and the exhaust flap. But doing that would allow the flap to move freely, and probably result in some rattling as well. Maybe one of the more technical folks on the forum can think of something and post it.

Plutoe

Not a problem talk to a tuner and determine if they can remap your ECU!!

cyberay

Thanks Plutoe, but I'd rather pursue a simple mechanical solution rather than have the ECU fooled with. In this case it's simply a matter of providing a constant vacuum source to the vacuum motors rather than a controlled source. It would be quite easy, I think, if I can determine either the vacuum hose routing to the motors or, in the alternative, the location of the electro-mechanical device that controls the vacuum to the motors. Maybe a visit to the local MB service department and a conversation with one of the techs is in order.