130 amp in a 85 cfi

[billison]

Ok, i'm wanting to upgrade my alt in my 85, it's a cfi car converted to carb, it does not have a volt gauge and the alt has 2 wires coming out of it. Do i need something special to do a 130 amp upgrade? or can i just get a alt out of a 94 and the wires off it and wire it like you do the 87=93 cars? thanks

 

[jrichker]

The 85 wiring is different from th later models. Here's the conversion diagram:

The main changes I would make would be to use a 4 gauge
power feed wire from the alternator to the starter solenoid
and a 125-150 amp fuse.


Any car that has a 3G or high output current alternator needs
a 4 gauge ground wire running from the block to the chassis
ground where the battery pigtail ground connects. The best
place for the block ground is where the battery ground for the
starter bolts down. The 3G has a 130 amp capacity, so you
wire the power side with 4 gauge wire. It stands to reason that the
ground side handles just a much current, so it needs to be 4
gauge too.

The chassis ground and battery pigtail ground go to the bolt being
pointed at in the following photo.

Picture courtesy timewarped1972

 

[billison]

ok so i can do it then, i posted on another site and one guy was saying i have to buy a special convertion kit and nother guy said with my car haveing a amp meter i could not upgrade, but i might not have understood them

 

[billison]

ok, let me get this right, the "a" wire goes back to the red grommet and the "s" goes back to the stater,both back on the alternater, the red grommet gets fused and then connects to the +side of the solenoid, what exatly does the "I" wire connect to? And i just remove the old wires then? thanks

 

[jrichker]

The I wire goes to a one side of a dash lamp with a 500 ohm resistor wired in parallel. The other side of the dash lamp and 500 ohm resistor goes to the switched 12 volts that is hot in the Run position.

 

[billison]

ok, i don't have a volt meter in my dash with it being a 85, and it don't work anyway after i pulled the computer to install the carb, would just a key'd 12 volt be ok? or do i need to find this wire?

 

[jrichker]

The I wire is the regulator wire that tells the regulator to turn on and feed power to the field windings in the alternator. Use the dash lamp bulb & 500 ohm resistor to feed power to this circuit. The lamp & resistor limit the current flow in case of a regulator failure, so don't skip using them.

 

[billison]

ok, any special way to find it? should it be in on of the stock alt wires? It seams odd the alt connects to it's self twice..thanks for your help

 

[jrichker]

The I wire is connected to switched power. That means it taps into the ignition or accessory side of the ignition switch or fuse panel. The reason for that is so the regulator doesn't turn on the alternator windings and drain your battery if the engine isn't running.

AutoZone wiring diagrams

http://www.autozone.com/servlet/UiB..._us/0900823d/80/16/71/3c/0900823d8016713c.jsp for 79-88 model Mustangs

http://www.autozone.com/servlet/UiB..._us/0900823d/80/19/59/5a/0900823d8019595a.jsp for 89-93 model Mustangs

http://www.autozone.com/servlet/UiB..._us/0900823d/80/1d/db/3c/0900823d801ddb3c.jsp for 94-98 model Mustangs