It's the last lap of your Street Stock championship race. You're driving the race of your life, passing your archenemy on the outside in a daring display of driving mastery. Suddenly, the engine goes silent. Turns out that wiring you duct taped together in the spring decides to let loose. Oops.
More often than not, wiring is one of the last things considered when building a car, and it shouldn't be. I've seen plenty of fellow racers doing wiring at the track before hot laps on opening night. But having a quality wiring job is easily within reach for the Street Stock racer, and all it takes is a little patience, some knowledge, and the following tips. We'll start at the battery and follow the path all the way to the front of the car, covering everything in-between.
The battery is the fuel tank for the wiring system. It pays to use the best battery you can afford. Manufacturers such as Turbo Start have developed AGM (absorbent glass mat) technology, which provides long life and less chance for failure due to the elimination of the plates normally found in a battery. The AGM battery is sealed and poses no risk of acid leakage. Consider using a 16V battery. As Street Stock racers, we tend to use stock starters, which just can't take the heat of headers. The extra voltage of a 16V battery will eliminate the hot start problems so common in the Street Stock ranks. A 16V battery also can increase ignition firepower on HEI or other stock-type ignition systems.
You should also take the time to research some of the smaller battery companies. As battery technology moves forward, you can find some cutting-edge products that just aren't available at Wal-Mart. For example, TheV Lite Battery, an AGM battery, weighs less than 33 pounds, which is 2-3 pounds lighter than the conventional Wal-Mart special. The next step up is a full-on racing battery. Performance Distributors' DUI Dyna-Batt is a dry-cell racing battery that weighs in at a feather-like 13.5 pounds.
This rear mounted battery...
This rear mounted battery shows the main ground wire, with a secondary ground running to the front of the car.
Electricity requires a ground in order to flow. The power side of the wiring receives all the attention, but the ground wiring is just as important. A bad ground can cause all sorts of mysterious troubles. Start by grounding the battery negative to the chassis. Mounting a stud on the chassis is an excellent idea. Be sure to clean the mounting point until it's shiny by using a wire wheel or equivalent. The stud will be your main ground point for the entire car. For rear-mounted batteries, run a 10-gauge wire from the ground stud to a convenient point near the front of the car where you can mount another stud. Attach any of your ground wires to this one.
Next, take the cap off your HEI. You'll notice that the coil is grounded. Run a wire from that ground, through the cap, and all the way to the negative post of the battery. This will ensure a properly grounded ignition system. In addition, your high-rpm efficiency can be improved by doing this. If you're using an MSD box or equivalent, you will need to use a heavy ground wire. Run this ground wire to the stud installed above.
The green ground wire is run...
The green ground wire is run from the coil ground and then attached to a dedicated ground stud-welded to the frame or to the negative post of the battery.
The main disconnect switch is an often overlooked component that can be very beneficial from both a safety and reliability standpoint. The main disconnect is used to isolate the battery from the rest of the car. Be sure to show your track's safety crew where your switch is and how the switch operates. It just may save you in the event of a crash.
When charging the battery, turn off the main disconnect to protect your valuable ignition control from voltage surges. When working around the starter, the disconnect can prevent the dreaded wrench sparking syndrome so often responsible for burn marks on your wrenches and possible damage to your ignition.
Running the alternator charging wire directly to the battery will allow the disconnect to isolate the power from the rest of the car during an emergency. The is done because, depending on where the power wire is attached, the alternator can power the car even if the battery becomes disconnected from the circuit.