Well I'm finally getting some work done on my intercooler sprayer, so here's part 1
the ultimate sprayer requires ultimate gauges, so that's up first.
I decided to install a water level gauge for the water tank, a pressure gauge, and a pre and post IC temp gauge.
The first two gauges are pretty straightforward and will not be covered here in great detail. Basically, like all gauges, you have 5 wires to run, two for lighting that connect to your dimmable dashboard circuit (easily tapped behind the radio from the harness that's made for your OEM boost gauge or OEM tripple cluster). The second two wires are gauge power, which I ran from my power outlet, so the gauges are on when the radio's on. I can check water level and so forth without starting the car. The last wire goes to your sender. You also need to GROUND your sender if its not connected directly to something that's bolted to the chasis. There are plenty of gauge install threads on this board and other so I'm not going to go into it again.
The third gauge I installed was an SPA Digital Dual Displat temp gauge. SPA makes about 20 different dual display gauges with just about every possible combination of two readings you may want. pressures, temperatures, whatever. They are sold as a kit that contans all necessary senders, wiring and so on. They're really great. The gauges start ar right around $200, and bimmerworld.com seems to have the best prices for them.
I chose to install my water spray-related gauges together on my A-pillar using a Lo-tek tripple gauge pod for wagons. ** Wagons have a different A-Pillar ** so make sure you get the right one if you have a wagon.
here's a shot with most of the electricals for the 2 "common" gauges already done, with a larger hole drilled for the SPA gauge. Since the SPA gauge comes with a harness and all wires have waterproof connectors already on, you'll have to drill a somewhat bigger hole to get the wires through.
plastic conduit is your friend..helps keep all your wires from getting tangled