I would suggest you put one in between the pump and the injector and keep the other as a spare.
This is where if you are tuned for meth and have advanced your timing to help produce more boost if there is no liquid flowing will do the most damage. ( destroy your engine)
One on both sides of the pump is over kill IMO.
Also on a side note, I have a solenoid and boost switch from my coolingmist kit that I would be willing to part with and is advertised in the for sale threads.
Originally Posted by Ben Crowson
I was thinking one between the pump and solenoid and one between solenoid and nozzle- they would have to be activated when the solenoid is activated since they are flow based units and not pressure switches (ie there is no flow in pressurized line between pump and solenoid when solenoid closed).