Alternator swap
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From: La Grande, OR
Alternator swap
I would like to change out my alternator on my '87 F150 out to a higher amp alternator. I have a lot of off-road lights, as well as a winch system that is going on sometime in the near future. Right now, with just my stereo, the headlights dim everyonce in awhile, and when I go through a puddle while mudding, the amps drop (im guessing until the water spins out). It is a serpentine belt system, and I think that it puts out 60-70 amps, but I don't know.
To handle the new load, I was thinking of putting on an alternator from a '94 Crown Victoria that puts out 100-110 amps. They're both internally regulated, so I didn't see a problem. However, the guy at the parts store said that if I did that, I would be running a huge risk of frying my electronics, mainly, the EFI computer. He said that because of the difference in charging power, I would overload the system (but as long as it's regulated it's ok right?).
So my question is, is he right? I've seen some people do these kinds of swaps, and I know that companies sell high-amp alternators, so what gives? Thanks for all the help
To handle the new load, I was thinking of putting on an alternator from a '94 Crown Victoria that puts out 100-110 amps. They're both internally regulated, so I didn't see a problem. However, the guy at the parts store said that if I did that, I would be running a huge risk of frying my electronics, mainly, the EFI computer. He said that because of the difference in charging power, I would overload the system (but as long as it's regulated it's ok right?).
So my question is, is he right? I've seen some people do these kinds of swaps, and I know that companies sell high-amp alternators, so what gives? Thanks for all the help
Fleet Owner
Joined: Aug 2005
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From: Easton,Ks
Originally Posted by nighthawk285
To handle the new load, I was thinking of putting on an alternator from a '94 Crown Victoria that puts out 100-110 amps.
Originally Posted by nighthawk285
They're both internally regulated, so I didn't see a problem. However, the guy at the parts store said that if I did that, I would be running a huge risk of frying my electronics, mainly, the EFI computer.
Originally Posted by nighthawk285
I would overload the system (but as long as it's regulated it's ok right?).
Originally Posted by nighthawk285
So my question is, is he right?
You will have to run a higher gauge wire from the alternator to the starter solenoid, about an 8 GA in place of your 10 GA wire. Also you will need a 12 GA fuse link in it.
Last edited by subford; Nov 23, 2006 at 07:00 AM.
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Alternator only puts out as many amps as needed, up to its max capability. The max capacity is also dependant on alternator speed. Guy at the parts house doesn't fully understand the system. There are some really sharp experienced guys at parts houses, but many are not. Those jim dandy cumpertized alternator testers are not real good either. Had Auto Zone and Advance test my junkyard 3G before I installed it. No Good, according to both. Took it to an old time alternator shop with a crude set up to drive the alternator. They said it is good. Put it in a few months ago and it is fine.
Do a Google search for a 2g to 3g upgrade. Lots of info with step by step instructions, and pictures. Nice thing about the upgrade is the 3g can produce as many amps at idle, as the 2g at full speed.
If lights dim after running thru water, it is probably cause the belt is wet and slipping.
Good luck Frank
Do a Google search for a 2g to 3g upgrade. Lots of info with step by step instructions, and pictures. Nice thing about the upgrade is the 3g can produce as many amps at idle, as the 2g at full speed.
If lights dim after running thru water, it is probably cause the belt is wet and slipping.
Good luck Frank
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From: La Grande, OR
yeah I thought that he was sketchy, as i had never seen him before. i didnt think thait would hurt anything, or they wouldnt sell higher-amp alts, in the aftermarket.
Thanks for the help,
On second note, the lights don't only dim when going through water, but also when my stereo is up loud and all the lights are on.
Thanks for the help,
On second note, the lights don't only dim when going through water, but also when my stereo is up loud and all the lights are on.
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Joined: Apr 2005
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Forgot to add it is a Bosch alternator. It orginally had a standard regulator but the place I bought it from swapped the single wire for no charge.
Total costs
Alternator - 85
Fuse and holder 20
Cable (used old jumper cable) 0
Ken
Total costs
Alternator - 85
Fuse and holder 20
Cable (used old jumper cable) 0
Ken
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Joined: Nov 2006
Posts: 1
Likes: 0
Your lights dim because your system is taking all the juice. That is, if you have a full setup-amps, subs, all that jazz. My '94 has a good alternator, but if I turn up the bass and the volume, I can still make the lightsdrop a little.
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From: La Grande, OR
Originally Posted by 300-6banger
Your lights dim because your system is taking all the juice. That is, if you have a full setup-amps, subs, all that jazz. My '94 has a good alternator, but if I turn up the bass and the volume, I can still make the lightsdrop a little.
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From: Bend,OR
go to www.fordfuelinjection.com click on products. site has 3g alts of various outputs, and also pre made wiring harness's and the fuseable link that is important when running any larger then 100amp alt. I run a 95amp currently and wouldnt feel good having lights and good stereo running off of it. 130-160amp is the next upgrade so i can run all of those things and a winch.
