Wanted to do a little update since it's been a while. The car's been on jackstands in the garage for several weeks now but will hopefully be coming down this weekend, so thought I'd get things started with a small project I just completed.
As anyone who's followed this build knows, I've been running Varex mufflers on stock exhaust piping for a while now. Hilariously I originally bought these mufflers years ago for a different car, but they ended up being an absolute perfect fit for the Z4. The coolest part about them though, being that they're internally valved to be straight through or "turbo" style.
You can see in the above (dirty) picture they have a removable tip (which the included one fits the stock cutouts in the bumper perfectly) and that little box looking thing is the motor that opens and closes the valve. Now although this setup has been installed on the car for close to a year, it took me quite a while to actually run the wiring into the cabin to actuate the valves. When I finally did, I realized the closed position was so quiet as to not even be useful, which basically killed my interest in the project, so I left it in a state of half-completion.
With the car up in the air for the past few weeks however, my gaze slowly crept towards the exhaust again. It sounds great with the mufflers "open", but is almost silent with them "closed". I want something that sounds great "closed" and insane when "open", so exhaust piping has been acquired and will be going on soon. In the meantime though, I figured I'd address the unfinished switch/wiring.
I had originally purchased a rocker switch with the required polarity switching (the valve operates by switching polarity to open/close), but this style of switch proved to be much too tall. It would need to sit above the surface of the center console to fit, which obviously would work. So I went about designing a relay setup, momentary button switches, and a housing to make it fit/look better.
I'd actually done this once before on one of my old cars, but had to re-draw the diagram to remind myself of how it worked.
And then assembled it in real life
Properly sized switches were easy enough to find on Amazon
And then I hopped into tinkercad to design a housing that I could 3D print. Took a few iterations but eventually I ended up with something that looked like this:
Obviously it doesn't fit perfectly flush, and using simple screws to attach it to the cubby isn't the most elegant, but for the amount of work I was willing to put into it, I'm pretty happy. Tinkercad is a pretty flexible design application, but nowhere close to what I'd need to create something with OEM fit.
From there I installed in the car, and now she's ready for the work this weekend to commence!
