Boost Controller
http://www.greddy.com/upload/file/PRofec_Bspec2.pdf
My opinion, worth 2 cents, is that if you're keeping it simple, then why not simply use a manual boost controller? You can always upgrade, or update in the future.
Regardless, it looks like the harnesses for that controller, are easily replicated, just won't be "plug in" unless you also buy/use some weatherpack or whoever's connectors. The MAC valves, hose, fittings, etc., can be bought all over the internet. Amazon probably has most, if not all, of it. You can absolutely "T" two MAC valves together.
I totally understand wanting some control. My controller has just two boost setting presets. I use the main one (default), as my "low" boost, and the 2nd one as my "high" boost, or in my case, triggered with an external "scramble" button, since I bracket race.
I datalog every pass and made myself a little laminated "cheat sheet", which tells me (pretty closely) what % to set my controller at, for a specific amount of boost, and ET (footbraking). I can pretty closely dial in anywhere from mid 11's to mid 9's, and anywhere in between, and may try some 10.0 Index class racing this year, so I 100% get what you want to do.
So, to run a 10.0 index, using transbrake, I'd need 40% duty cycle on the mac valve, or 50% if footbraking, since car is obviously slower (or mine is anyway). Then tweak it a few % one way or the other to get dead on.








