Sorry to drag up a really old thread. This is a very creative solution. I have been considering doing something like this but with a vacuum/ catch can and pluming it to both the pvc/intake manifold and the exhaust-powered E-vacs so in theory when manifold vac goes down, the evacs kick in. Just need to figure out a crossover for the two vacuum sources but it seems like it would work well. How did you do the crossover from your vacuum pump? or did you just run it as the only option?