Inline fuse necessary for 3G upgrade?

[Luvmy88]

HI all-


I've got the 4ga wire already for my 94 3g alt upgrade. I've read I should put a fuse in line from alt post to the selenoid, like a 200 amp fuse.

Is this really necessary? Or a safety thing? I will be putting a large load on the alt with a big stereo system.

Thanks

 

[Muirracing]

IT actually.... is highly Recommended.....that you use a inline FUSE
you should use a 150 amp fuse


I have finished my Upgrade with no problems....U will be so Happy u did!!!!
I'm pushing a Big stereo System as well.....
That night I finished..... I NOTICED A HUGE DIFFRENCE in the GAUGE
lighting ...... AWSOME>>

 

[hllon4whls]

Is this really necessary? Or a safety thing? I will be putting a large load on the alt with a big stereo system.
Thanks

Imagine how you would feel with your car burned to the ground with you narrowly escaping it. It is that serious of an item. If you dont think it is important, you are just nuts.

Dont believe it cant happen to you. It can and if I know how most people wire stuff, it probably will.

 

[leakyfaucet]

The stock alternator didn't have a fuse. So I assume the reason people put fuses on the bigger ones are because they are capable of doing more damage to the harness?

 

[Mustang John]

Well, since I ran a 0 gauge welding cable around my radiator support from the alt to the batt, I fused both ends at the alt and the batt. In an accident, it would likely be injured, and the fuses would help reduce the arcing and chance of fire I figure.

I can be anal sometimes... But, better safe I spose...

 

[hllon4whls]

The stock alternator didn't have a fuse. So I assume the reason people put fuses on the bigger ones are because they are capable of doing more damage to the harness?

It sure did. There was a fusable link near the starter solenoid.

IMO, only one fuse is needed. That is one as close as possible to the bat or soleoid. If there is a short, this fuse will open and keep the bat from starting a fire. If the alt grounds out the fuse by the bat will pop and isolate the battery; the car will kill, the alt will stop producing power and there will be no fire.
You may lose the alt, but you wont get turned into bacon before your time.

 

[leakyfaucet]

So that's what those colored things are . If a fusable link broke, did you have to replace the wire or what?

 

[Sgt.5point0]

I actually had an alternator shop make my power wire for the swap that included a new fuse link rather than that big ugly fuse.

 

[sn9550]

You can get the fuse and holder from here. www.evparts.com It's in the marine-rv section under fuses. Mega fuse holder #FU5520 $16.95, 150A Mega fuse #FU9523 $5.90. More practical and cheaper than a wafer stero type.

 

[90mustangGT]

My wire didn't come with a fuse in it and I haven't run one either. I've heard people for it and against it, but I really didn't bother.

I had a bad expereince. A little piece of insulation wore through right after the wire hookup on the alternator. Everything charged and all, and it didn't kill my alternator. I don't know how long this went on but it got hot enough so when I tried to take off the 10mm nut, the stud came off with it. I took it to a alt. shop and the had to replace the whole rectifier because it is one peice. Cost me $57, Alterstart might have replaced it for free but shipping and down time didn't make it worth it. I am not sure a fuse would have saved me, but maby it would have.

 

[tmoss]

I am not sure a fuse would have saved me, but maby it would have.

It would not have saved you - your problem sounds like it was from a loose connection, not too much current. Electrical systems in Hospitals get infra-red scans each year to detect these types of loose connections.

 

[88POSLX]

Last summer I was at a store and my car wouldn't start. A few guys pushed me and I clutch started it. Instantly my belt started squeeling like a bastard. I drove the two blocks home and shut it off. Damn starter wire burned through on my longtubes. Didn't damage the alternator though, luckily. I don't know if a fuse would have prevented this though.

 

[9350notch]

I did a 3g upgrade last summer. I used the factory wiring...is this unsafe?? Also, is the performance of the alternator affected?? Will the battery charge more if I wired up a 4g wire instead?? Also...I still have the '95 pulley on it, is there a different pulley anyone is using that is better?? Thanks in advance.

 

[jrichker]

I did a 3g upgrade last summer. I used the factory wiring...is this unsafe?? Also, is the performance of the alternator affected?? Will the battery charge more if I wired up a 4g wire instead?? Also...I still have the '95 pulley on it, is there a different pulley anyone is using that is better?? Thanks in advance.

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.

 

[FoxChasis]

And if you think that puny (stock) 14GA fuse-link is going to protect the circuit, I'd like to show you the (original, 2G) burned-out alternator and melted wiring harness that was in my '86 GT. Had the fuse-link worked like it was designed to work, the wiring would not have melted and the alternator would not have caught fire.

Don't do it half-assed. Install the properly sized power wire and inline fuse. And DO NOT leave the original power wire connected to the alternator. (Leaving the original wire connected to the alternator will defeat the purpose of having a fuse inline with the new wire, if that fuse happens to blow.) Just leave the original wire connected to the starter relay only.

 

[90mustangGT]

Thanks TMOSS.

It seems the 3G units take some abuse. Most alternators fry out alot more easily. Next the Chevy guys are going to be using our 3G's like they love the 9" rears.