How much alternator needed?

[Chris-90LX]

I've decided to do something about my low charging issues. I installed power pullies a while ago and there is no way my stock (75 Amp) system can keep up with charging the battery the way it should at idle. It hasn’t been a problem yet, but it just doesn’t do it too well!

I don't have a large demand for power. The car has a stock stereo system in it and it doesn’t even have a rear window defroster.
What do you guys suggest? Is there a simple way to check what I should install to cover the pullies?

Who has the best kit for bumping up the amps?

What should do it, 100, 130, 140 or more?

 

[houstonstangguy]

i just posted this in another thread. I think it still pertains to you as well.

my battery just started dying within the last 2 weeks. i couldnt figure out why. i replaced the battery and it still started draining. i took it around the corner and they told me the alt worked sometimes and sometimes it didnt. cost me 15.00 to find out for sure the alt either had a short or was going bad.

I called pep boys and oreilys for a 94-95 gt 130a alt. they wanted between 119.00 with a 35.00 core and 139.99 with a 20.00 core. I posted on my local club site and one of my buddies on there told me he just swapped out his for a 130 and the 96 up v6's are all the same 130s that the 94-95 gt used. he gave me the name of the name of the salvage yard he used and sure enough they had 3. I got a 2000 v6 130a alt. for 35.00 with a 10.00 core and a 91 day warranty. not bad at all. I had to get the plug with it and solder that plug on.

I figured why do a stock 75 again when I can get a 130 now. it wasnt a big deal at all. the slight grinding of the bracket was the worst simply because i only bought a grind bit and not a drimel. a drimel would have taken about 10 minutes i would guess and having done just a bit on my drill i would say get the drimel. lol

if you decide to do the 130 email or pm me and ill show you where I got the instructions with step by steps. just make sure you get the plug with it or you will have to make your own.

 

[95BLBLVert]

Keep in mind that even if you go with a 3G alt. it will still only put out X number of amps at idle due to the underdrive pulleys. Higher output alts typically use smaller pulleys. If you use an alt underdrive, you are defeating the purpose of using a higher output alt. An alt. must run at a 3:1 alt/crank pulley ratio. In other words, the alt spins 3 times the speed of the motor. Underdrives change this ratio. A 3G alt will put out a little more amperage than your stock unit, but will not run at peak efficiency until you're at cruising speeds.

 

[powershift351]

definitely 3g alt with smaller pully

 

[TRWXXA]

Don't forget to upgrade the wiring when you put on the higher amp alternator.

The stock wiring is barely capable of handling the stock alternator's maximum output. If you put on a high-output alternator without upgrading the alternator-to-battery wiring, you're just asking for a fire.

 

[95BLBLVert]

I make a 4-gauge fine-stranded power wire with inline fuse specifically for alt. upgrades. Let me know if you need one.

 

[powershift351]

sweet 95BLB, how much, I am about to upgrade myself

 

[04sleeper]

Don't forget to upgrade the wiring when you put on the higher amp alternator.

The stock wiring is barely capable of handling the stock alternator's maximum output. If you put on a high-output alternator without upgrading the alternator-to-battery wiring, you're just asking for a fire.

Good call! I used 4 guauge wire from the alternator to the starter solenoid (Battery side) to replace the factory wire. Also got my alternator from Autozone for the 94-95 for $109.00 with a lifetime warranty. I also changed the pulley for an overdrive alternator pulley from Summit for $18.50 part number ASP-520004.

 

[95BLBLVert]

You'll need a power wire upgrade like this or similar to it: