140 alternator upgrade - wiring question

90lxfoxbody

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Jan 11, 2006
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i bought a 140 amp alternator off of ebay from a guy who makes them in his shop. he has 100% feedback and before i bought it i contacted several people who bought them from him. all of them had good things to say, so i bought one. the alt bolts in with no modifications and uses the stock wiring harnesses. it even comes with the 6 rib underdrive pulley. sweet. so i have heard that a wiring upgrade is necessary for the increased output. the alt is replacing my 75 amp stocker. i have read that i need to change a wire to a 3 gauge. which wire is it - color, etc. and how do i change it out? is it one of the wires that is in the harness and plug that fits into the alternator? if someone has done this upgrade i would appreciate any input. ( and of course the input of the generally knowledgable guru's on stangent is always welcome ) thanks.
 
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thank you prosc - but i think i may need further information. this alternator is a direct bolt in - same housing as the factory alternator. it is a 2g alternator. so do i need to upgrade to a 3 gauge wire since there is no hot wire that attaches to the back of the alternator?
 
8950HO said:
140 amps through the factory spade connector and wiring:eek:.
I hear that! No way would I run more than stock amperage through that stock cable(s). I would bring this up with the vendor/seller.

FWIW, Some of the 94-95 guys use that guy's alts and have said good things about the units.
 
No longer 100% feedback now, lol.

And yeah, based on everything I have read, do it right and upgrade your wiring. 2G or 3G, that is still a lot more amps than the stocker. Electrical fires/meltdowns = Bad...then again, that is just IMHO.
 
The issue I see is that the stock connector doesnt allow one to upgrade the wiring. It's not like there is a ring terminal on a 2G to attach a new cable to.
 
Dbeck002 said:
Is it necessary to keep the stock orange/black power cables wired up to the 3G even after using heavy gauge cable?
No. The simple way to do it is to leave the fat connector (with the stock charge cables) taped up and hidden on the alternator side.

On the other end, Just leave the connections as they are on the solenoid (so you dont fart with the switch and sense wiring).

I dont recommend connecting the stock cables (connected to the alt itself) if you did the 4 AWG cable upgrade anyhow. It's unnecessary and could lead to issues in the event of a failure.
 
and yet again!!!!! where's our 3g/alt sticky? sticky sticky sticky:D

yes now this is an interesting one, stock alternator housing, 140 amps, and upgrading the power wire......hmmmmmmm

all i can say is, that seems so appealing to use that alt but, he should give away fire extinguishers with them.
 
timewarped1972 said:
and yet again!!!!! where's our 3g/alt sticky? sticky sticky sticky:D

yes now this is an interesting one, stock alternator housing, 140 amps, and upgrading the power wire......hmmmmmmm

all i can say is, that seems so appealing to use that alt but, he should give away fire extinguishers with them.
Right on Target!!!:D
 
So then i ran the power wire from the alt to the soloniod on the fender..guess thats no good huh? I should take it off and go straight to the battery, that could explain the surging i have every once in a whille when i kick my fan on at idle!!