For many years, the Mustang was a simple car. The original dream of a small and relatively light platform with a small-block V-8 and rear-wheel drive, with a bunch of options to individualize the owner experience, has been a hallmark of the Mustang right up through the mid-1990s. Later into that decade, the Mustang started packing on standard features, safety equipment, and more, leading to the Mustang we see on dealer lots today. Sure it is still rear-wheel drive with a V-8 under the hood of the GT, but today you'll also be getting stability control, traction control, ABS, power everything, HID headlights, electric power steering (EPAS), and much more. All of these features add up to a lot of power consumption and it's not unheard of to find 130-160 amp—and in some cases 200 amp—alternators. However, the everlasting Fox era Mustangs, while short on electrical needs when new, often pull double duty as rolling concert halls, race cars, and more. Their stock 65-amp alternators just won't cut it when these cars start seeing electrical upgrades.
The alternator in the '86-'93 Mustang is considered a 2G alternator. It has a single power plug on the side of the case along with a bolt-on internal regulator and plug-in stator connection. The rectifier/power plug can be a fire hazard due to excessive resistance and poor internal design of the 2G unit. In 1994, Ford reengineered their alternator to fix these issues. The new 3G based alternator featured an internal fan design, integrated regulator, and higher output. But don't think that a 3G alternator upgrade is just for late-model owners. The 3G unit uses the same 7-inch spacing (from pivot to fixing holes) as the '65-'85 1G alternator. This means you can upgrade your vintage Mustang, Mustang II, or early Fox's 1G unit with the power and reliability of a 3G alternator.
The 3G alternator starts at an impressive 95 amps, but you can also find 130-amp and higher models through aftermarket sources. One such source is PA Performance. PA's alternators are 100 percent new and fully load tested during assembly. They also include the voltage regulator and correct pulley. The 130-amp model, which we're installing here, puts out 80 amps at idle and a maximum of 160 amps! That's nearly triple the output for a bolt-in charging upgrade. Your stereo amplifier, aftermarket ignition box, high-output coil, and more will thank you for this upgrade!
The 95-amp unit is indeed a direct fit into the Fox-body's cast aluminum mounting bracket, while the 130 amp unit requires a minor amount of bracket trimming to clear one of the alternator case bolts, plus an additional charging lead to support the increased output.
While PA Performance does sell direct, they have a large dealer network to order from, which can help with shipping times. In our case, Mustangs Unlimited was our closest dealer and since we needed a few additional parts for this aging '89 hatch, we got everything we needed from Mustangs Unlimited quickly.
1. This stock 2G alternator...
1. This stock 2G alternator has seen better days but until now has kept up with the electrical needs. However, the owner of this ’89 5.0L hatch recently added a huge amp and speakers and plans nitrous and a high-power ignition system as well. It’s time to step it up.
2. As with any electrical...
2. As with any electrical upgrade or repair, step number one is to disconnect the battery. You want the system “dead” while modifying or adding wiring. The stock rectifier plug, which is where the 2G’s problems often manifest, is disconnected first, followed by the regulator and stator connectors. We’ve also removed the air filter for more working room, but this step isn’t completely necessary.
3. The stock 2G alternator...
3. The stock 2G alternator is held in place by two bolts, a 5⁄8-inch pivot bolt and a 9⁄16-inch fixing bolt. The 9⁄16-inch fixing bolt is being removed here. You can see we’ve already removed the serpentine belt.
4. Once you have both bolts...
4. Once you have both bolts out, the 2G alternator is free to be removed from its mounting bracket. There is a steel compression bushing where the lower bolt passes through that might make things tight. Give the alternator a little back and forth wiggle and it’ll push the bushing in enough to free its grip.
5. You can skip the next few...
5. You can skip the next few steps for the 95-amp alternator, but for the small amount of extra work we really suggest the 130-amp unit. There is a small amount of grinding to the bracket required, which can be done on the car if you like, but we removed the bracket to keep aluminum shavings away from the engine compartment. The bracket is retained by a 9⁄16-inch bolt, shown here, and two �-inch bolts on the opposite side of the vertical support. You will also have to remove the Thermactor air pump mounting bolt (but not the pump itself) if your Fox still has the pump installed. This ’89 clearly did not, as you can see by our lead photo.
6. As noted in our opening...
6. As noted in our opening text, the PA Performance alternator comes out of the box with all new components and even the pulley already in place. The 130-amp alternator is PN PA1619 ($189.95). The upgraded charging cable kit is a Mustangs Unlimited part and is PN EZ130F ($104.95). Note, however, that PA Performance requires a 4ga charge cable to maintain their lifetime warranty on the 130-amp unit (recommended on the 95-amp as well).
7. Fitting the 130-amp PA...
7. Fitting the 130-amp PA Performance alternator to the bracket with just the pivot bolt will show you where the alternator interferes when you pivot the alternator into place.
8. Mark the aluminum rib with...
8. Mark the aluminum rib with a paint pen or crayon and grind/cut away the material to allow the alternator to fully pivot into place, as seen here. This modification took less than five minutes with a pneumatic cut-off wheel, but could just as easily been done with a good hacksaw.
9. Depending upon casting...
9. Depending upon casting tolerances, you might need to grind a small flat spot at the fixing point ear to clear the new alternator case. If the case rubs, grind the ear for clearance; if it doesn’t, you’re fine. We went ahead and followed the included instruction sheet and made a little more room between the alternator and the bracket ear. Reinstall the aluminum alternator bracket and the new alternator back onto the engine. The alternator comes with a new fixing bolt, as the top ear is now a metric thread.
10. Wiring changes will depend...
10. Wiring changes will depend upon which wiring adapter you use. For the Mustangs Unlimited harness, we used the one-wire connection. The only thing that you’ll have to cut and crimp is the green wire with red stripe from the old voltage regulator plug. This is the alternator “turn on,” or exciter wire, that comes from the dash’s charge indicator light.
11. The remaining connections...
11. The remaining connections to the Mustangs Unlimited harness are shown here. From left to right we have the voltage regulator (plug-in), the stator wire (plug-in), and the main charging lead (bolt on).
12. The 3G uses the newer...
12. The 3G uses the newer power lead attachment method (and much like the vintage Mustang’s 1G) of having a battery terminal stud on the rear of the case. Simply slip the ring terminal over the end of the stud and tighten the supplied 10mm nut.
13. The Mustangs Unlimited...
13. The Mustangs Unlimited charge lead needs to be routed to the battery or positive side of the starter solenoid. To reach this location, the new charge lead is routed under the alternator and across the top of the water pump to the opposite side of the engine compartment.
14. The inside diameter of...
14. The inside diameter of the ring terminal on the end of the Mustangs Unlimited charge lead is a bit too small to fit over the starter solenoid’s stud. Using a pair of locking pliers to secure the terminal, a step-style drill bit made quick work of opening up the inside of the terminal to the proper size. DO NOT hold the terminal with your bare hands, as a drill bit can catch the terminal and quickly injure you. This is also why we prefer the step-style drill bits, as they rarely “grab” the metal. Mount the ring terminal to the solenoid as shown and secure any wiring with tie wraps to the Mustang’s OE wiring.
15. We did not have a load...
15. We did not have a load tester available, but a simple voltage check across the battery terminals with the Mustang at idle showed a nice bump in charging voltage of nearly half a volt (stock was 13.89 at idle). As with any electrical/charging system upgrade, it is imperative to check your grounds, battery cables, and battery condition to get the most out of your upgrade.