Steve Baur
Former Editor, Modified Mustangs & Fords
August 1, 2008
Peak Performance from your ponycar comes from more than just moving air in and out. You must make sure it starts and fires every time. Quit depending on old, stock parts to meet the demands of your high-strung horse, and get a charge out of PA Performance's 130-amp alternator conversion and high-torque starter.

It Seems there's no end to what Mustang enthusiasts can do with their ponycars, whether it's tripling the horsepower output, slashing lap times, or shaving seconds off of their elapsed times. Doing so often involves numerous modifications to the Mustang, and while everyone's always willing to bolt on the latest and greatest speed part, sometimes the rest of the vehicle gets left behind. Such is the case with the Fox-body charging system.

Electric fans are a common early mod, followed by additional fuel pumps, nitrous-oxide solenoids, and high-powered ignition systems, not to mention big stereo systems. Most people don't think about the little stock alternator struggling to keep up with electrical demands that are two and three times out of its operating range. Luckily, PA Performance has been thinking about this for years, and has the products you need to keep that voltmeter hanging high.

"Typically, a stock '87-'93 car had either a 65-amp or 75-amp alternator," says PA Performance's Rick Harmon. "Some suggest that the 65 was used in hardtops and the 75 was for convertibles. We can't find any statistics to prove it, but that makes some sense. The downfall of the stock units was that they only made 20-25 amps at idle. That was barely enough, and then most people added underdrive pulleys or accessories, which just destroys the alternator and battery. Fox-bodies are notorious for slow turn signals and slow power windows when they're stock. Add anything to the system or change the pulleys, and they die."

Electric Fans are often the first mod that starts to tax the stock charging system. Half the time, used pieces from newer cars are pirated and installed, and while they will eliminate the drag on the engine, they do pull on the charging system more than necessary. This is Flex-a-lite's Xtreme electric fan designed specifically for your 5.0 Mustang. The fan draws just 18 amps of current, and comes complete with everything you need for a neat, factory-like installation.

The '94-'95 SN-95 Mustangs came stock with a 130-amp alternator, which was better, and many Fox-body owners retrofitted them to their earlier horses. Unfortunately, these alternators produce only about 50 amps at idle. Comparatively, the PA Performance 130-amp alternator (PN 1608; $199) that we're installing here offers 80 amps at idle, and a maximum of 160.

Our subject vehicle for this charging system upgrade is a '92 Mustang that has been outfitted with a nitrous-oxide system, an aftermarket ignition box, a high-capacity fuel pump, and an underdrive pulley system. It's the usual list of suspects in a dimming headlight situation, and one that we were about to exacerbate with the addition of an electric fan.

All electric fans are not created equal however, so we called Flex-a-lite for one of its Xtreme cooling models. We had sampled the Xtreme fan on our '93 Cobra project, Stolen Goods, and were extremely pleased with the fit, finish, and operation of the unit. When the need arose for another electric fan, we didn't hesitate in ordering the Xtreme, which draws only 18 amps, yet delivers a stiff 3,300 cfm of airflow. The Xtreme also utilizes a thermostat control unit whose operation can be configured in a variety of ways. The Flex-a-lite Xtreme fan (PN 185) retails for $320.

In addition to the alternator and cooling-fan upgrades, we also installed PA Performance's PMGR mini starter, which sells for $135. The last few times we drove the Mustang, the starter was hanging open, so we knew we needed to remedy the situation. We also opted to upgrade the factory alternator wiring using PA Performance's four-gauge Power wire kit (PN 9902; $59). The stock wiring is only designed to handle what the stock alternator provides, so more power from a new alternator should be complemented with a heavier delivery system.

With PA Performance specializing in charging systems, we posed some questions to PA's Rick Harmon. As you'll find out, there's much more to a simple alternator swap than meets the eye.