Alternator Questions

[03_SVT COBRA]

Well recently I got the battery light while driving and took it to Advance Auto to see what the problem could be (already was thinking it was the alternator, but ehh). So they told me the alternator was starting to die since is was not charging correctly.

So I started looking at alternators and realized it is a little more complicated than I thought. The car has typical intake and exhaust, along with a smaller upper pulley (one on the Eaton), she dynoed at 481HP/506TQ @14psi. So now knowing the basic engine mods, here is are my questions:

1. What alternator should I get?
-PA Performance Alternator 130 amp
-PA Performance Alternator 170 amp
For the 170 amp, would need to upgrade the wiring system?

2. Bigger Alternator Pulley?
-Since I believe the lower pulley is stock, is there a need to swap alt pulleys?
-If I get the 170 amp alt and put the larger pulley on it, will it still make "170 amp"?

As far as I know, the larger pulley is good for extending the life of the alternator, but will it still produce enough juice?

 

[jrgoffin]

Gets asked about weekly.

This will help:

http://www.modularfords.com/threads/235857-Terminator-quot-Alternator-101-quot

 

[MineralCobra]

Alternators are known to go on these cars, main killer is the heat and location.

When my alternator went out it would charge ok when car was cold and in colder weather but once it was hot and heat build up in the engine bay voltage would drop to 11ish.

I tried the 170 amp alternator from ebay vendor that many had luck with.. for me it sucker voltage would drop at random times etc.

Finally went with NAPA unit, it has lifetime warranty and so far it's been treating me good. I did make a heat shield between the alternator and the headers, I also wraped my primary tube closest to the alternator to remove some heat. The regulators do not like the heat and headers/manifold are right there.

Hope this helps, that's just my experience.

 

[Stage 4.6]

Theirs a lot of info on the alternator failures on this forum, but in a nutshell i also went with the various recommendations from here, and after 2 consecutive failures I went with the stock ford alternator and it came with 3yr warranty I installed the 3.5 Metco pulley on it and have had no issues in the over 2 years.

Check out TERMINATOR FAQ theres a link for the alternator issues.

 

[Bdubbs]

I've only had one fail so far in the 7 years I've owned my car. It looked like a oem motorcraft unit.

Last year I upgraded to the nations alternator with external regulator. Also did a wire upgrade.
https://www.svtperformance.com/forums/threads/my-first-review-of-nations-200-amp-alternator.1118055/

 

[Comp04svt]

Another option is Justin Wheelers 200a unit and wire upgrade. Search for J2Fabrication on facebook. A lot of people on the cobra facebook pages run his alternator, including myself, and I've yet to see someone post about any issues. Also nice that it is a direct replacement, and you wont have to deal with any alignment or fitment issues.

If you have an upper only and no lower, you don't necessarily NEED a bigger pulley, but it is definitely not a bad idea. I would do no bigger than a 3.2 so you don't run into undercharging concerns at idle. Justin sells a slightly larger pulley than stock that would probably be ideal for your setup.

 

[BossBlock302]

This is a pretty good tutorial I found. Seems the stock alternator is under-powered and you want to go with a bigger power/ground cable (this dude went with a big 3 upgrade) once you go to a higher amp alt.
Its also good to run your brake line ducts to the alternator to cool it down and possibly add a heat shield.

 

[03_SVT COBRA]

Thank you for all the replies!
Although I still have a question
130 amp or 170 amp (with wire upgrade)?

 

[03_SVT COBRA]

Also what is amp for the stock alternator?

 

[holiks03cobra]

I wouldn't buy a PA alternator. I had issues with both of mine. The first one, something broke inside and the pulley wouldn't turn the internals. The second one burned up and almost caught fire. I currently have a Wheeler alt and my only complaint is the volts at hot idle are on the low side.

 

[03_SVT COBRA]

LOL, I am going to just get the 130 PA Performance Alternator.
I need the car running again, it is a daily driver. I don't push it hard. I am in college and don't have much money, so I will just wait next time to get either nations alt or mechman alt (both of those seem really good but ).

As far as I know running 130 should be fine, right?

 

[Bdubbs]

Might as well give it a try. Alternators fail a lot on these cars. Some work for others and some don't.

 

[jrgoffin]

Also what is amp for the stock alternator?

Read the link I posted.

 

[hotcobra03]

I have been using parts store alts..lifetime replacement

I did come across issues with ground wire from battery to radiator support..

It was melting inside where it wasn't seen..

I upgraded that ground only and noticed I have higher volt reading now in car..

Was getting 14.1 at battery but low 13s in car..

Now I see 14.5 at start and 13.9 hot with ac on..