Grounded For LifeAnother important area within the electrical system that rarely gets attention is the ground circuit. Even the simplest electrical circuit requires a power source, wiring that connects to a load (like a lightbulb), and wiring to complete the ground circuit back to the battery. But when performing electrical-system repairs, it's the ground circuit that is often ignored. The classic example of this is a dragging starter that begins after the battery is relocated to the trunk. The installation often includes a large multistranded positive battery cable from the battery to the starter, followed by a wimpy ground strap usually connected to a corroded sheetmetal connection. This creates a poor ground circuit that causes grief once the engine warms up and resistance increases. The fix is to add several large ground cables between the engine, the frame, and the battery to ensure a solid ground circuit all the way back to the battery. If you have any questions about the validity of your circuit, perform a voltage-drop test (see "Drop It").
Getting ConnectedAll electrical devices require dozens of feet of stranded wire and connectors to make all this happen. While voltage loss is proportional to increases in wire length, the big voltage-drop culprits are connections. This is especially true with poor connectors or hastily performed temporary fixes that become permanent repairs. A poor connector or a power feed line that has been spliced several times can quickly become a focal point for many electrical problems. There are several ways to make a good electrical connection, but we'll go over just one. The key is to make the connection as permanent as possible in order to prevent problems from occurring later.
The best way to create an excellent electrical connection is to use quality terminals instead of those cheesy plastic-coated connectors. Stick with the standard non-insulated connectors. Use a quality wiring stripper and crimping tool, and if you're really motivated, you can also solder the connection to ensure minimal voltage loss. With that done, you can finish the connection by covering it with a length of shrink tubing.
Most musclecars can benefit from a live 12-volt power source under the hood near the battery. If you've ever seen a positive battery terminal with six or eight different wires leading off the terminal, you know that it's less than attractive, let alone barely functional. The much cleaner alternative is to mount a terminal near the battery that is fed from a large 8-gauge wire from the battery. This terminal can then feed high-current items like an MSD-6 box, stereo amplifiers, nitrous solenoids, and electric fans.
Adding CircuitsAnother difficulty facing car crafters that wish to upgrade their older supercars is that there are usually very few extra electrical circuits in these older cars that offer fusible circuit protection. Adding extra circuits on an as-needed basis is clumsy. A much more expedient method is to employ one of those add-on circuit boxes available from companies like Painless. These are pre-wired circuit boxes with built-in ATO-style fuses that can manage several circuits without overloading your existing fuse box. The biggest hassle would be finding a place to mount the box. Then all you have to do is wire up the circuits you want to add and you're ready to run. Painless offers these slick units in universal 3-, 7-, and 12-circuit blocks complete with fuses and a heavy-duty relay. Painless even offers a 12-circuit universal pre-wired fuse block that will replace your existing fuse box. These kits are very easy to install and will give a professional look to your wiring system.