What We Did
Replaced the old and worn-out alternator with a 130-amp DUI unit
Keep the jumper cables at home.
While most DIY-ers out there don't necessarily have a car full of expensive electronic devices to run, we do, however, still need a properly charged battery for cold-cranking in the winter months. And if you've got a slew of interior instruments to run and upgraded headlights, LED taillights, EFI, or an underdrive pulley, then the factory-style alternator may be straining to recharge the battery while driving. If you find yourself continually charging your battery only to find it weakened time after time, the alternator may be to blame.
In a nutshell, an alternator is the car's own charging system and is spun by the engine's drivebelt. The alternator converts mechanical energy from the engine's drivebelt into electrical energy. Once the engine is running and rpms rise during driving, the alternator spins, recharging the battery. But smaller-diameter pulleys don't have the ability to spin the alternator at the rate necessary to recharge the battery. Also, things like heat generated from an overworking alternator may also contribute to a weakened charge for the battery.
While our project '72 Nova only had an aftermarket head unit and four relatively small speakers, we did have a three-gauge pod and a G-Tech unit to power. We also have plans in the works to install more accessories, including an electric fuel pump, which could potentially strain our aging factory-style alternator. We needed an upgrade. DUI offered up a Mr. Amp (130-amp) alternator as a solution, but also offers a 190-amp version. They'll maintain peak performance in the ignition system and even produce 65 amps at idle, which help eliminate battery drain on underdriven pulley applications.
Fortunately, replacing an alternator is a cinch. Using only handtools, we removed and replaced the old alternator with a more efficient Mr. Amp alternator. We go step by step to give you the rundown on how to do one yourself.