Alternator question

1991stanggt

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Sep 23, 2003
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I have a question...i have a stereo system in my 91 gt and i was thinking about getting a better alternator. Then i realized maybe i could just switch the one from my moms 97 mustang with mine since hers is stored and rarely driven anyhow. Would it provide more power and would it be an easy swap?

thanks
 
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Modulars use different alternators than the fox. You need to do the 3g swap. You can find them on numerous cars, liek the sn 95's, or the ford taurus also works. If you want a brand new unit, go with either Pa performance or a guy on ebay named ALTERSTART. The 3g must be wired differently, but not a big deal to do
 
1991stanggt said:
I have a question...i have a stereo system in my 91 gt and i was thinking about getting a better alternator. Then i realized maybe i could just switch the one from my moms 97 mustang with mine since hers is stored and rarely driven anyhow. Would it provide more power and would it be an easy swap?

thanks

I agree with TIMMY2734. Do the 3G upgrade. Alterstart has 150 amp alternators for about $120, with a lifetime warranty. PA Performance has a great wiring upgrade kit for about $50 (you'll need the standard-long or premium-long kit).

Do a web search for the 3g alternator upgrade and you'll find numerous articles with step-by-step instructions.
 
Carney Woods said:
not to steal the thread but what does the 3g upgrade mean?

3g is the new alt that ford started using on the stang in 94. It has a 130 amp output as opposed to the 75 amp alt that cam on the fox V8's. Foxes can be upgraded to the newer style with a little bit of bracket and wiring modifications.
 
plastic_cow said:
What sort of wiring upgrade needs to be done? I just ordered my alt but didn't hear anything about rewiring my 3g 160 amp alt for an 88...
Thanks

The 3g alternator puts out way more current than the stock wiring can handle. You have to upgrade or you could fry the stock wiring, as well as the rest of your car.

A minimum of 4 ga wire should be used between the new alternator and the starter relay (or battery). An appropriate fuse or fuseable link should be put in-line with the new wire. PA Performance has reasonably priced upgrade kits that include everything you need for the new wiring.

Do a search online for instructions on how to do the upgrade. Some of the old wiring needs to stay in place for proper electrical system function. The bigger power wire just bypasses the old wire between the battery and the starter relay.
 
plastic_cow said:

If I'm not mistaken, you'll need to look for instructions on how to do the upgrade from an external voltage regulator, stock setup. A couple more steps but still pretty easy, as I recall.

Hardest part is trimming the bracket for clearance of the new alternator. Borrow a small die grinder if you don't have one. A Dremel took me an hour, and I went through several cutting wheels. I can't even imagine trying to use a file, except for final smoothing of the cut edge.

Enjoy your upgrade. It's nice pulling up to a stoplight at night with all your lights on, your a/c fan on high, the stereo cranked, and NOT seeing your battery discharging. :nice:
 
Here's websites with pictures...

See http://www.geocities.com/smithmonte/Auto/3G_130A_Alternator_Upgrade.htm - all the tech data you could ever want to know
OR
http://www.fordmuscle.com/archives/2001/03/paperformance/index2.shtml
OR
http://www.mustangcentral.net/tech/alternator.html - excellent pictures of installation

For the right way to do the wiring. Some people will tell you that you can skip the wiring upgrade, but it will catch up with you sooner or later. A fire in the wiring harness is ugly and expensive.