Anyone with problems doing the 3G swap with stock wiring?

smokin 91, i was told that the 6G alternator with straight clocking, eg the ears 180 degrees from each other, like we need for our 5.0's, came on 2000-2004 mustang 3.8 v6's. i too got mine from ebay and it is wonderful. not like that delco style one wire piece of crap. i have yet to fuse my charge lead, but i know i have a circuit breaker floating around here someplace. should i use 100A or 150A for a 130A alternator?

Use a 150A fuse.

smokin91' said:

Use a 150A fuse.

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If you read the write up at http://www.geocities.com/smithmonte/Auto/3G_130A_Alternator_Upgrade.htm he recommends a 125A fuse for the following reasons:

You can use a 125-150A fuse. I chose the 125A because fuses should be sized to protect the lowest rated component in the line. In this case, the alternator is 130A and the 4AWG is 136A. Also, fuses do not blow at their rated value. The time it takes it to blow is depends on the current flow as a percentage of the fuse's rating. At 140% (175A) of this fuse's rating, it will take it 200 seconds to blow. At 180% (225A), it will take 6 seconds; at 280% (350A), it takes 1 second.

Makes sense to me. As for my set-up, I bought the PA Performance 4ga wire upgrade and it came with a 200A fuse! I am going to eMail PA today to see why they did this and also to have them clarify their recommendation of using the OEM charge wires AND the 4Ga wire.

DucatiRdr said:

If you read the write up at http://www.geocities.com/smithmonte/Auto/3G_130A_Alternator_Upgrade.htm he recommends a 125A fuse for the following reasons:

You can use a 125-150A fuse. I chose the 125A because fuses should be sized to protect the lowest rated component in the line. In this case, the alternator is 130A and the 4AWG is 136A. Also, fuses do not blow at their rated value. The time it takes it to blow is depends on the current flow as a percentage of the fuse's rating. At 140% (175A) of this fuse's rating, it will take it 200 seconds to blow. At 180% (225A), it will take 6 seconds; at 280% (350A), it takes 1 second.

Makes sense to me. As for my set-up, I bought the PA Performance 4ga wire upgrade and it came with a 200A fuse! I am going to eMail PA today to see why they did this and also to have them clarify their recommendation of using the OEM charge wires AND the 4Ga wire.

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Since you are going to rattle their cage, please include this with my name and email address. jrichker@yahoo.com:

"Here is the reasoning behind using only a single 4 gauge fused power feed to the alternator. If you use the two 10 gauge black/orange wires in addition to the 4 gauge wire, you have two fused power feed paths. The current in a parallel circuit divides up according to the resistance of the branches. The total current capacity of the wiring is the sum of the fused paths. The 4 gauge path is fused for 125 amps, and the two 10 gages wires are fused for 60 amps. That is a total of 185 amps, which exceeds the capacity of the alternator. Overload can occur without the fuses blowing, damaging the alternator."

I just got off the phone with PA Performance. I've got to say that these people are very good to deal with. When I first called to order my parts they answered a bunch of questions and continued to do so today. Here is what they had to say:

Regarding the fuse. The 200A fuse was chosen because there is a 20% variance in the rating of a fuse and he said most are over-rated due to liability concerns, then there is an additional 20% variance based on ambient temperature so the actual rating of the fuse can be as low as 128A when you do the math which is 2A lower than the rating of the alternator. He went on to say the fuse was made for a Ford vehicle by Littlefuse. At one point they sold the wire kit with fuse to the engineer who participated in the design of the fuse itself and the engineer sent along a 3 page letter on why the 200A was a good choice. In a nutshell the fuse was chosen to prevent the system from shorting out as you drive down the road, but will work if you bash up the front end while the alternator is pushing current.

As for JR's question. PA did agree that the 10ga wires are underrated, especially for an uprated alternator. He did say that omitting the 10ga wires from the equation was optional - some people have, others haven't but he has yet to hear of a problem. He did say they are relying on the fusable links in the 10ga wires to offset any problems. No real comment on the multiple wiring paths exceeding the current capacity of the alternator except that they have not had any problems despite 1000s of units being sold.

I just used the Powermaster 140amp alternator and called it a day. Very EZ just one wire that came with it and that's it.

cliff88145 said:

I just used the Powermaster 140amp alternator and called it a day. Very EZ just one wire that came with it and that's it.

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That's what I had...but I'd always have to rev the engine to start it charging. And when the regulator failed and started giving me 19 volts, I replaced it...only to have it totally drain my battery. Thankfully it is an Odyssey battery, which can survive being discharged to only 5.6 volts I got a 6G alternator and noticed that it had more amps capacity at idle, because the voltate did not fluctuate as much as with the one wire GM alt. BTW my Powermaster was 2 years old when it failed and the warranty was only 1 year. I had that thing on my 2.3 before I even had my 306.