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Race Car Wiring

Wiring a race car or your street ride can certainly be a daunting task for the person who has little to no experience with electrical work. The basic goals are to connect "some" device to the battery of the vehicle in a manner that is safe, has solid connections and electrically correct. This article isn't meant to be a replacement for the gobs of books that you can find at any bookstore on the subject, but rather just some interesting tips and tricks that I have picked up over the years in performing this type of work.

As pointed out in one of the latest Camaro project pages, my first big tip is to purchase one of the wiring kits available if you are starting from scratch. The amount of time you can spend to collect everything you need plus the time spent building the system just doesn't justify the small amount of money that a kit cost. Even if you are doing a street car, I have found complete kits for as little as $150 that have 12-15 circuits in them. If you need more than that, they can usually be added either by the maker of the system or yourself.

On our latest project, we decided to go with a Painless Wiring system and it was an easy choice as I had installed the same type of system from them in my dragster a few years ago. If you follow the instructions and have all of the components in place, you can wire up a race car in an afternoon of work. The tools and pieces you need in addition to the kit would be a good pair of crimpers, an extra supply of solderless connectors and normal hand tools.

Wiring Tips

#1. Decide on the circuits you need first, then buy or build to suit.

#2. Don't be afraid to modify what you have, either adding to it as needed or removing what you don't want.

#3. Better connections are made via soldering the wire to the terminals. You don't have to find solder terminals, just cut or pull off the insulation jacket from a solderless term, place a length of heatshrink on the wire, place the wire in the terminal, crimp, then solder. After it cools, push the heatshrink in place and heat until it conforms to the terminal/wire combination.

#4. Use an old hair dryer as a quick source of heat for heatshrink. You can also take the plastic cap from a paint spray can, drill a few 1/4" holes in the top and use that to capture the heat from the hair dryer. You can shrink the heat shrink tubing with this method in just seconds.

#5. Use another plastic cap with two v-slots cut into it 180 degrees apart. This can serve as an extra pair of hands to hold wires together to allow you to solder them.

#6. When you need to add a wire to an existing one, do not use those Scotchlock connectors. They will fail, usually as you're staging for the final round in a million dollar race. Instead, very carefully slice the insulation of the wire that you want to splice to and remove it from a short section completely, leaving the wire exposed. Twist your new wire evenly around this point, apply solder and in this case, wrap with 3M brand electrical tape. 3M is the only tape you should buy, nothing else is worth purchasing.

#7. When wiring heavy continuous run electric motor items or any other item that takes a great deal of current, plan on using relays. The relays should be located close to the item they control and normally if you group them you can provide one large positive feed and split it among them. This saves running multiple feeds to the item and saves your expensive switches from continually arcing internally each time a component is turned on. Primary examples are fuel pumps, water pumps, radiator fans, headlights, shifter solenoids or NOS solenoids. Radio Shack sells a very nice compact relay that is easy to wire and install.

#8. Layout all of your wiring for everything before you start making the first connection. That way you can group your wiring together and decide if you can minimize or gang assemble feeds or grounds. An example would be the lighting for an array of gauges. One feed split off to each bulb and one ground connection is all that is needed, not an individual pair of wires for each light.

#9. Grounds are very important. You should consider grounds in the same manner as you think of providing battery voltage. Without a good ground path, all the voltage you can get to the component will be wasted. Along with grounding the battery to the frame, additional grounds should be provided from any ignition panel and between the engine and frame itself. Do not rely on solid motor mounts to provide your ground path.

#10. Wiring leads to ignition coils and crank-trigger systems should be spun together. This is simply taking both lengths of wire and twisting them together. This will reduce the inductance voltage that tends to form around leads of this type and reduce the chances of ignition misfire.

#11. Build a testlight from a 12v light bulb, long run of wire and aligator clips. You can use this to test your wiring, switches and connections before connection to your components to make sure you have everything right. It just might save an expensive ignition box.

#12. Never install an unfused or unprotected circuit. If one burns up the car, I can guarantee that one will be the one that does it.

#13. Make a wiring chart as you buid the system, it can come in real handy later when you ask yourself "did I use pink for the tailights or transbrake?".

#14. Don't use butt connectors to lenghten wire. Strip the insulation, put heatshrink tubing in place, mingle and twist the wires together, then solder. Push tubing in place and shrink. You now have a connection that will never come apart.

#15. Need to join three or more wires together, say two joining to one? An easy way is to take a large solderless connector that will accomodate all three wires, cut the ring or spade part off of the terminal and crimp the remaining barrel portion onto the wires. A touch of solder and heat shrink and you have a perfect connection.

#16. If your connections are going to be exposed to a lot of moisture such as the lighting on your race car trailer, consider placing a dab of clear silicone on the connections. The silicone will help keep out the moisture and reduce the chances of corrosion.

#17. In your race car keep an extra fuse taped to your fuse panel. It could make the difference in winning the next round or help you get back to the pits for repairs.

#18. After you have finished the last connection, protect your wiring by covering it with a wire covering. The stuff is cheap, keeps your wiring from getting pinched or cut and allows you to make easy additions in the future. Only tape wrap wiring that you are absolutely sure is never going to be added too.