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.

MM&FF: What are the most common misconceptions you hear with regard to Mustang charging systems and requirements?

RH: We hear it all, but most people think that an upgrade is an upgrade, and truth be told, all 130-amp units are not made equal. There's a price difference for a reason. The OEM 130-amp units are better than the stock Fox 65-amp units, but they're a far cry from what we build. We also build 200- and 240-amp siblings to them. The other unfortunate situation is that people are selling really bad-quality units on eBay, and they're giving everyone a bad rap because of high failures and low output.

MM&FF: Is it important to wire auxiliary pumps and fans with a relay. If so, why?

RH: I would say that wiring anything with a high-amp draw can be helped with relays. Electrically, it makes sense to let the relay handle the larger loads, but it also helps to protect the alternator. The voltage regulators are fragile, electrically. Back in the '60s and '70s, the "test" for an alternator was to remove a battery cable while the car was running. If the car died, then the alternator was bad. With today's sophisticated electronics, that's the worst possible thing people can do now. The arc or voltage spike created by doing that is deadly to an alternator's circuit, and any computer in the car can really be harmed by that. Improper jump-starting procedures can do that, too. Remember the old rules: turn both cars off, hook the cables up by positive-to-positive, negative to ground then start the good car, then start the dead car. People just tend to let the good car run and then connect positive-to-positive and negative-to-negative, and when that last connection is made, there's a big spike from positive to ground.

MM&FF: What should one look at when considering an upgrade to an electric fan?

RH: That's certainly an individual decision, but there are a lot of good cfm fans out there that don't draw a million amps. One thing we see a lot, which can be a misconception, is that people buy the OEM fans from a wrecked Lincoln, Contour, or other car, and although they move air, they draw about 60 or so amps. That's just not necessary, and it's hard on the alternator and battery. The other thing, with any larger amp upgrade, is the wiring. People tend to use wire that is much too small. Electricity is like air to an engine. You can have 1,000 hp, but if you have a 1 1/2-inch exhaust, it won't breathe. It will run, but it will be restricted. Electricity is the same. If you have a big alternator, you need big cables and grounds, as it has to complete the circle efficiently.

MM&FF: What are the most important things one needs to consider when buying a PA alternator?

RH: The most important things in buying any alternator are quality and size. Make sure you buy as much quality as your budget allows. Our units aren't for everyone-we get that, but we do build the highest-quality and highest-output units at each size level on the market, and support that with tech and customer service. We also go one more step in offering a wide range of conversion plugs and kits to adapt the modern technology units safely to the older cars where they can utilize that power reliably.

Another thing is to do the math and make sure you're buying one large enough (in output) to do the work. Alternators aren't meant to work at 100 percent capacity, so buy it with reserve. Volts and amps are inverse, so buying extra capacity not only gives them room to grow, it also yields a higher static voltage in the car-and we all know that ignitions, fuel pumps, and accessories love voltage.

You May have to test fit the PA alternator to make sure you have clearanced the bracket enough, but once that's complete, there are just two more bolts to install. PA supplies a new top bolt.

One area people get wrong is pulley ratios. An alternator needs a minimum speed to make magnetism (amps). When people have cars that idle very low or they have power pulleys (or a combination of both), they need to calculate pulley sizes to move that alternator back into the range that it will make magnetism. This is not a "brand" issue but a physics issue, and many people call us because they put a new alternator on the car and the volts are still low, or the windows go up slowly. Many times this can be solved with a $10 pulley and some simple math. The same can be said for the high-end builds. People build engines and computers to take 8,000 rpm, but they don't slow down the accessories (i.e., alternator), and then at the top end, they blow them up. We put a pulley sheet in every box and have a calculator on the Web site. We'll also do the math on the phone with customers. Making sure the alternator is spinning within its design limits will assure long life and excellent output.

MM&FF: How do the PA starters differ from the factory '92-later models.

RH: Essentially, we have sourced all new parts for these with lifetime warranties. They're the same size as the '92-and-up starters, but they're stronger, and the high-quality parts make them unique. Ford made these in a variety of outputs (torques). A 1.1 kw was the most common, with some cars moving up to 1.5, and 1.7 on the trucks. We build them all at 1.4-1.7 kw. Unfortunately, there are some people who import these things for like 35 and 40 bucks. They look pretty and sell fast on eBay or the Internet, but they aren't very good quality. It's hard to tell from the outside, but there's quite a wide range of quality.