Your Corner Wrench: Don’t get shorted on power when upgrading your project car

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There’s nothing wrong with improving performance on an older ride. Whether modernizing old electronics or upping the ante on creature comforts and audio systems, shade-tree techs have been reaping such benefits for years. Sometimes, however, those add-ons can take a toll on a limited electrical power source that the vehicle originally came with. Higher output ignition systems and sound system amplifiers, for example, can draw more electrical power than the engine’s generator or alternator can supply, leading to discharged batteries, engine trouble, and all-around frustration.

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If you’re working on a really old beast with a generator and external voltage regulator and would like to keep proper appearances, some manufacturers such as Powermaster Performance sell one-wire units with internal regulators. Though retaining an original-looking casing, these products can charge your project up with an efficient modern power-plant. These can be a handy way to get rid of rusty external regulators and their often-crusty wiring.

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If you’re dealing with a more modern alternator and space isn’t a problem, it’s often easy enough to source a higher output unit and adapt or replace the mounting bracket for a proper fit. Even if you aren’t running a particularly common vehicle, this method often just requires spacing the alternator’s mounting points to ensure proper belt alignment.

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If space is a problem (or you’re really a stickler for original looks), consider getting the original unit rebuilt and rewound for more output. There still are repair and rebuild outfits out there, but sometimes it takes a little hunting. There’s also a limit to the power increase with new windings and stators, so don’t expect to be able to double the output within the same case.

Even with the proper power, you can be limited by older fuse panels and wiring. Vehicles were built and designed to serve their purpose, and many DIY techs find out the hard way that small fuse panels and bare-minimum wiring can cause power drops after certain upgrades. It’s great to have an HEI ignition system, but if the headlamps dim to the point of not being safe, what’s the point? Remember it’s the alternator/generator that supplies all the power, not the battery. Tackling a full rewire of even the simplest vehicles is not a task for the light of heart (or experience), but in the long run, it can save a lot of headaches in dealing with burnt circuits and damaged electrical components. And again, for popular rides you can often find ready-made kits; just don’t expect them to be plug-and-play.