Among the systems that get very little attention in any performance car is the electrical system. For the most part, electrical systems function fairly efficiently, but there have been many advances over the last 30 years, so there are several areas that could stand improvement. Let's go over some of these and what you can do to make the electrical and charging system perform up to the level of the rest of your performance ride.
Charge ItThe basic automotive electrical system employs a battery, starter, and alternator. The alternator is the heart of the system, since without it, you won't get far. Early alternators were a vast improvement over their DC-generator forebears, with most alternators cranking out a maximum of 60 to 70 amps. This was because they were only asked to power the headlights, heater, and maybe an AM/FM radio, and none of these demanded high-amperage output at low speeds. But today's cars usually include air conditioning, high-output electric fuel pumps, and twin electric fans, not to mention a thumper stereo and other electrical accessories. So high-amperage output at low engine speeds is now in great demand.
Given this increased demand, late-model internal regulator alternators are now designed to pump near-maximum output at idle. This is a great reason to switch to a later-model-style alternator that can handle the load of a typical electronically enhanced street machine. Add up the load of a pair of 20-amp electric fans, a big electric fuel pump, headlights, heater or A/C fan, and a few amps for the stereo and you're looking at a load in excess of 60 amps. This is far greater than the max output of a '60s alternator. There are several companies now delivering high-output alternators, including Powermaster, Bosch and Performance Distributors, as well as the OEM's. Don't be fooled by the small diameters of these late-model alternators. These smaller units are capable of 100 amps or more output even at relatively low alternator speeds.
Some confusion exists in the area of one-wire alternators. These are self-energizing alternators that do not require a separate feed-wire connection to energize the alternator. The term "one-wire" comes from the fact that the heavy alternator charge wire is the only wire connection required to the alternator. Most factory alternators are generally three-wire connections with a pair of small wires that complete the control circuit.
OEM style internal regulator alternators use an external 12-volt connection to signal the alternator to begin charging the moment it begins to spin. One-wire alternators instead rely on attaining a given internal speed to create a sufficient internal voltage to begin the charging process. One-wire alternators need to achieve a sufficient rpm to begin charging, usually around 1,500 to 1,800 engine rpm. So the only thing you have to remember when using a one-wire alternator is to lightly rev the engine once after starting in order to trigger the charging circuit. Some companies like MAD Enterprises suggest that the one-wire alternators do not do as good a job of maintaining system voltage and can be difficult to replace in the field, which is why MAD suggests using a three-wire alternator instead.