Anyone working on 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.

 

Resistor from motor to +12

 

Hey Mitch, if you are referring to the vacuum motor, there is only a diaphragm at that point. The solenoid that controls vacuum to the diaphragm is located elsewhere, and therein lies the problem. To provide constant, or switched, power to it I have to find it. Trying to trace the vacuum lines to it hasn't worked because they disappear out of view. Any idea where it might be?