130 Amp Taurus Alternator Swap
Thread Starter
Senior Member
Joined: Jun 2007
Posts: 346
Likes: 2
From: BC
130 Amp Taurus Alternator Swap
So I had the same problem alot of the S4 guys are having... the stock 70A alternator is barely enough to keep up with the stock system never mind a car with fans, stereo, amplifiers, etc....
So after doing some searching, I discovered some people on the forum have done Taurus alternator swaps... it's a 130A alternator, and because there are so many Taurus's, they're pretty cheap. The swaps that I did find done here seemed too complicated, they were making crazy brackets to make the alternator fit.
I made a trip down the local junkyard and picked up a mint alt out of a 96 Taurus, 3.0 OHV engine. My research tells me a 3.8 alt will also work. Looking at the alt, I found a way to mount it without having to make the brackets.
The Taurus uses a serpentine pulley, and the pulley on the stock S4 alt doesn't fit onto the shaft of the Taurus alternator. Rather than drilling out the stock pulley, I made a trip down to a local alternator shop and picked up a brand new pulley slightly larger than stock (so I don't over-rev the alternator) that fit perfectly on the shaft of the Taurus alt.
The Taurus alt has two ears on it, one small and one big. I had to grind a little off of the small ear to get the pulley alignment just right. When grinding it, you have to make sure you keep the surface flat, so you dont throw the pulley alignment out on the vertical plane.
Once that was done, I realized that the other ear was too high for the stock adjuster bracket. I unbolted the adjust bracket, and made a small extension for it, drilling an extra hole in the oem bracket so the extension couldn't rotate, and three holes in a 1/4 piece of steel, bolted the two together and put it back on the car:
The belt was pretty simple- I need a belt 1" longer than the OEM belt.
Once I had the alternator in, it was a simple matter of wiring it up. The Taurus uses a system a lot like the FC. The main cable to the battery was upgraded to a 4GA, hooked up, run through a 150A circuit breaker, and connected to B+.
There are two other plugs on the Taurus alt, a single wire and a three wire. The single wire connects to the middle pin on the three wire, labeled "S". The two remaining wires are "A" (Yellow/White) and "I" (Green/Red). "A" Needs to be wired into constant power (I wired the original alt power wire to this, and "I" Goes to switched power, Black/White wire on the stock S4 alt harness.
Once that was done, I got to work on upgrading the ground wires on the car- I grounded the engine to the body using a tab on the back of the Taurus alternator, and an unused hole on the shock tower:
I grounded the body directly to the battery, connecting to an unused hole near the coil. You can see it (blue cable) in the picture below. You can also see the power cable running down to the circuit breaker, and and the new batter cables. The two small wires hooked up to the battery go directly to my voltage gauge:
Started it up, and boom, 13.86 V at idle
Raised the RPM a bit, to 1500, and was just over 14 V:
Hope all this info helps somebody!
-Dirk
So after doing some searching, I discovered some people on the forum have done Taurus alternator swaps... it's a 130A alternator, and because there are so many Taurus's, they're pretty cheap. The swaps that I did find done here seemed too complicated, they were making crazy brackets to make the alternator fit.
I made a trip down the local junkyard and picked up a mint alt out of a 96 Taurus, 3.0 OHV engine. My research tells me a 3.8 alt will also work. Looking at the alt, I found a way to mount it without having to make the brackets.
The Taurus uses a serpentine pulley, and the pulley on the stock S4 alt doesn't fit onto the shaft of the Taurus alternator. Rather than drilling out the stock pulley, I made a trip down to a local alternator shop and picked up a brand new pulley slightly larger than stock (so I don't over-rev the alternator) that fit perfectly on the shaft of the Taurus alt.
The Taurus alt has two ears on it, one small and one big. I had to grind a little off of the small ear to get the pulley alignment just right. When grinding it, you have to make sure you keep the surface flat, so you dont throw the pulley alignment out on the vertical plane.
Once that was done, I realized that the other ear was too high for the stock adjuster bracket. I unbolted the adjust bracket, and made a small extension for it, drilling an extra hole in the oem bracket so the extension couldn't rotate, and three holes in a 1/4 piece of steel, bolted the two together and put it back on the car:
The belt was pretty simple- I need a belt 1" longer than the OEM belt.
Once I had the alternator in, it was a simple matter of wiring it up. The Taurus uses a system a lot like the FC. The main cable to the battery was upgraded to a 4GA, hooked up, run through a 150A circuit breaker, and connected to B+.
There are two other plugs on the Taurus alt, a single wire and a three wire. The single wire connects to the middle pin on the three wire, labeled "S". The two remaining wires are "A" (Yellow/White) and "I" (Green/Red). "A" Needs to be wired into constant power (I wired the original alt power wire to this, and "I" Goes to switched power, Black/White wire on the stock S4 alt harness.
Once that was done, I got to work on upgrading the ground wires on the car- I grounded the engine to the body using a tab on the back of the Taurus alternator, and an unused hole on the shock tower:
I grounded the body directly to the battery, connecting to an unused hole near the coil. You can see it (blue cable) in the picture below. You can also see the power cable running down to the circuit breaker, and and the new batter cables. The two small wires hooked up to the battery go directly to my voltage gauge:
Started it up, and boom, 13.86 V at idle
Raised the RPM a bit, to 1500, and was just over 14 V:
Hope all this info helps somebody!
-Dirk
