Fox Whats A Good Size Alternator To Buy?

[James V]

Found out the current stock alternator (75 amp) will barely give enough power to run the electric fans. (as I'm sure most of you know the stock alternator is pretty bad) What would be a good size to replace it with? I saw a kit with a 160 amp on LMR.

 

[Mustang5L5]

110-130 is all the standard typical bolt on fox body needs unless you have a competition grade stereo system.

Start doing things like multiple fuel pumps, electronic water pump, etc and then you can consider going higher

 

[Bullitt347]

I run a 200 amp alt in my car, uses stock brackets.

 

[jrichker]

110-130 is all the standard typical bolt on fox body needs unless you have a competition grade stereo system.

Start doing things like multiple fuel pumps, electronic water pump, etc and then you can consider going higher

Here's a map for your journey...

Electric fan = 3G alternator if you want long life & reliability from your car.
The electric fan saves some HP. The stock fan's parasitic drag runs from 7-12 HP depending on who you talk to. The electric fan uses about 1/2 HP of power from the electrical system.

Figure this:
Ignition system & computer = 12 amps
Fuel pump = 12 amps
Exterior lights = 15 amps
Fan (heater or A/C) = 15 amps (can run between 5-25 amps depending on setting)
Radio & instruments = 10 amps
Wipers = 10 amps
Rear window defroster = 5 amps

That's grand total of 79 amps from a 65 amp alternator. Talk about overdrawn at the bank!

If you aren't going to waste money on a super stereo system on a car that has loud exhaust, the 130 amp 3G or 6G alternator is a very good choice. There is enough power to run all the stock electrical equipment and electric fan with no problems.

 

[James V]

110-130 is all the standard typical bolt on fox body needs unless you have a competition grade stereo system.

Start doing things like multiple fuel pumps, electronic water pump, etc and then you can consider going higher

I want to start doing more mods and HP adders eventually, should I get a higher amp alternator now?

 

[James V]

110-130 is all the standard typical bolt on fox body needs unless you have a competition grade stereo system.

Start doing things like multiple fuel pumps, electronic water pump, etc and then you can consider going higher

I want to start doing more mods and HP adders eventually, should I get a higher amp alternator now?

 

[mikestang63]

any 94-99 3G alternator from a Mustang will work

 

[Bullitt347]

You have to add up the amp draw of all your accessories that consume power and then go about 20% larger than that. In my case I have 2 electric smog pumps used as an crankcase EVAC system, one electric cooling fan, electric water pump, FAST XFI ecu, Aeromotive Eliminator fuel pump, Rule I/C water pump, Boost controller, Bosch water pump for supercharger, trans brake solenoid, line lock solenoid, MSD ignition system and oh, yeah, the headlight and tail lights if needed along with power windows. So, yeah, 200 AMP 3G ALT.

 

[a91what]

250amp 3g alt. 3000watt stereo and usual powered goodies.

 

[Davedacarpainter]

You have to add up the amp draw of all your accessories that consume power and then go about 20% larger than that. In my case I have 2 electric smog pumps used as an crankcase EVAC system, one electric cooling fan, electric water pump, FAST XFI ecu, Aeromotive Eliminator fuel pump, Rule I/C water pump, Boost controller, Bosch water pump for supercharger, trans brake solenoid, line lock solenoid, MSD ignition system and oh, yeah, the headlight and tail lights if needed along with power windows. So, yeah, 200 AMP 3G ALT.

Please don't take this as an insult.....WOW!

 

[Mustang5L5]

I want to start doing more mods and HP adders eventually, should I get a higher amp alternator now?

All depends on what you do. If you just add an Efan, all you need is a 3G/6G 130 amp oem alt. If you start building the starship enterprise and need power for all sorts of things like Bullitt347, then you can go with a bigger alt. But for most fox mustangs, 130 is plenty

 

[Bullitt347]

If you start building the starship enterprise and need power for all sorts of things like Bullitt347, then you can go with a bigger alt.

Hmmm, Starship Enterprise....I like it! Could someone point out to me where engineering is located cause I have yet to reach warp speed...

 

[Davedacarpainter]

Hmmm, Starship Enterprise....I like it! Could someone point out to me where engineering is located cause I have yet to reach warp speed...

That'll take that larger dilithium crystal spec alternator.....I think it's rated at 14 bagillion watts. You'll need a different sized pulley.