So basically since I first got my 335i, I have been contemplating this. I wanted something simple that allows me to open and close the muffler valve when I want.
I've seen where some people have the little remote to open and close it. I can only see this being beneficial if you may be are able to open as much or little as you want, To dial the volume to the preferred level. I am at a point where I want it loud or quiet, not an in between. And given that BMW has generously provided us with our own butterfly valve, why not use it.
My plan is to use the connector that allows for the golf tee mod from inside the trunk. (If you are unfamiliar with what I'm speaking of, check out this thread,
http://www.e90post.com/forums/showth...t=Golf+tee+mod) Granted my plan still leaves you susceptible to the code logging that disconnecting the connector does.
Testing the wires of the solenoid circuit leads me to believe that the circuit is power switched, and the red is ground and purple is power.
So my thought is to Cut the power and put a banana connector in line. This allows me to go back to stock operation should I want to. Using a 3pin on/off/on rocker switch, Where the common pin is attached to the power wire going toward the solenoid. 1 pin goes to the remaining stock power wire.
at this point, You could use a 2 pin, on/off rocker, and be able to switch between stock functionality and the golf tee mod on the fly.
But because I plan on deleting the driver side muffler (like the aggressiveness of the muffler delete), I want to silence it on demand as well. So for the third pin I will run a fused line to a constant (at least when the ignition is on, going directly to the battery or a constant "on" source will drain the battery).
Honestly for my preference, I would likely be happy with an on/off rocker where it eliminates the stock operation. But I figured that since it isn't any extra work to have the 3rd option, I might as well.
I will post pictures and operation video once I finish, but for now am looking for input from electronic fans for any glaring issues.