Well I found a 3G at a yard for 50 bones... so I am thinking about getting it. I have been having some low RPM output issues from my 95 Amp.. I have a Fosgate 3002 running a single JBL GT120, and when I am sitting at idle, my Voltage meeter starts to fall back down around the 12 volt or lower range. I also have a voltage meeter built directly into my head unit and it shows that I am getting 14.1 + while running down the road with just the stereo and the lights going, it drops back down to the 13.5 range when running the heater and lights and stereo. However when I come up to a light as stated before it shows 12.3 ish... with the headlights running.. I always turn the heater off and the stereo down at lights just to avoid taxing the system too much.

So here are the questions... Should I go ahead and get the 130 amp 3G?
Could I get a smaller pulley for the 95 and get away with that or will it over spin the Alt at higher engine RPMs?

Also I remember reading something in the 3G swap threads that I will need to swap the 3G pulley for the one on my 95 amp. Is that because the pulley on the 3G is larger and will cause the same issues? Will my 95 amp pulley on the 3G be enough to solve this low RPM voltage issue?

Let me know your thoughts and or experiences with this issue.

 

From another forum: FullsizeBronco.com - 3G alternator FACTS

 

Putting a capacitor in your stereo system will help also.

 

Someone correct me if wrong..

Most of the 3g alt from models have a larger pulley on them..not much larger but just a little. I simply swapped the pulley from my 2g alt, since it was smaller. At lower RPM, the smaller pulley will provide more output, since it will be turning somewhat faster than the pulley that comes std. on older or maybe newer 3g's. I did the ssame as you and got one for 50$. it was off a '95 mercury.

Hope this helps

 

Upgrade to the 130 amp 3G.

Upgrade your grounds.

Upgrade your charge wire and add a fuse.

Do not waste your money on a capacitor.

If you have a smaller alt pulley throw it on the 130 amp for even better idle voltage.

 

Don't spout of random BS when you don't know what you're talking about.

Capacitors are no waste of money. They are a good thing to have if you have a sizeable amp. If your headlights are dimming when idling, you can use one.

 

I don't know that I would call a 300w amp a "sizeable" amp.... just sayin'

 

Obviously it's enough to cause some voltage fluctuations.

 

Considering the OP pointed out this

With the stereo down, and the heater off, dropping to NO output is not something to address with a capacitor, I would be more inclined to make sure all the connections are good, and change over to the 3G before I would just start throwing a capacitor onto it to try and fix the issue

 

I said a capacitor would help. I didn't say that's all he should do. Jeebus.

 

A capacitor is a device that will save your charging system.... If you are running an amp it really should be a "std" addition...

A capacitor's function is to level out the load to avoid spikes that occur EVERY time the sub "thumps"... higher the "wattage" the larger the spike.

That being said a capacitor won't "cure" a bad charging system but it will save a good one.

 

This is not BS... This is experience with car audio... Go to ANY car audio website and ask about a cap. Everyone there will tell you that you are wasting your money. Its a bandaid to covering up a bigger problem. Use that money and buy some bigger wire for grounds/better battery/ HO alternator.
I have a cap in my garage... Been there a longgg time. Want it? Ill give it to you.
Quick one using google.
http://www.caraudio.com/forums/gener...res-proof.html

 

Thanks for the input guys. And actually I have a capacitor sitting in my room now, only issue is I have had it for like... 12 years.. its a 1 Farad Street Wires... OLD SCHOOL Anyway, thats the reason I don't have it hooked up. I just figured its toast by now.. I really should just toss it out I guess... Oh and it was really nice to have when I had my Soundstream 6.0 running mono 1 Ohm load to two Pheonix Gold XS15s. Bass was alot punchier and my lights did stop dimming in my Grand Marquis.. But I also had an Optima yellow top to draw from so surely that helped too.

Anyway, in regard to this pulley thing, will I run the risk of over spinning the alternator with the smaller pulley at higher engine speeds, or will it stay safely in the alternators operational limits?

 

Actually it is both depending on setup......

So in some cases a CAP does NOTHING!
and in some cases a CAP does ALOT!

1) If you have a system that never draws more current than the battery w/ alternator running can supply then yes a CAP is a total waste of money, space, time, weight....

2) If you have a system in which your battery w/ alternator running can not handle PEAKS then a CAP is beneficial....

3) If you have a system in which your battery w/ alternator running can not handle ambient load and peaks then a CAP is a band-aide and again generally a waste.

So if you fall in case 1 DO NOT BUY A CAP!!! actually do nothing and enjoy...
So if you fall in case 3 DO NOT BUY A CAP!!! upgrade wires(power,ground), alternator, battery...
So if you fall in case 2 Buying a CAP is more economical!!! Why???

Simple you are spending less than all new bigger wire, bigger battery, bigger alternator.

In this scenario what is happening is:

First you have too much loss between source(battery) and load(amp)
Second a battery is designed for large storage and slow delivery and a CAP is designed for small storage and fast delivery(which is why CAPs help).


Generally speaking as in all cases and ESPECIALLY in audio if you don't understand what you are putting together and how each component of the system interacts with each other odds are you won't even come close to a good system.

 

I have read in several different articles about the use of a smaller pulley for idle output, but nothing "ill" about the effects of overspinning. Pretty much, it's only gonna put out so much output, hence you have the MEGA-Fuse tied in there to prevent it from doing so. In case the ALT's design is flawed, you have that fuse there to prevent major damage.

Hope that helps!