I'd like to occasionally disable the EBC for engine longevity, rain, noobs, and of course all those valet drivers.

I'm half assuming, half remembering that the DIY valve "fails" in open mode, so it'll be wastegate only.

I did this during my wet track day by setting the EBC table to zeroes across the board, and it saved my *** a few times when the track was still wet. Part of that was my lack of decent tire, but that's another problem.

My question is, should I run a relay to disable the 12v, or can I just run a switch in the signal line to disable it?

 

Switch is OK. Yes, when shut down, the solenoid stops bleeding boost to atmosphere.

Run hot to solenoid, then run to switch, then to MS, according to this: According to the Brain

 

Perfect, problem solved. Thank you!