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Discussion Starter #1
I know that this has probably been discussed many times, and I have searched the archives, but cannot find what I am looking for without reading hundreds of lines of text.
My question is this: Where should the "S"-terminal (Red wire) on a CS alternator be connected to?
I know that the connection goes to the "Batt" terminal and many simply connect a short wire to that terminal. However, GM did not do this. They connected it somewhere up in the harness. What is the reason for this? Are there some other reasons that help performance? Also, I have heard that it is suggested that you should upgrade that wire to an 8-gauge wire instead of 10-gauge. How much current is this wire carrying? I know that it can't be the full 105A because that would take at least a 5AWG wire to carry less than 300circular-mils per amp.

Oh...I am going from a 63amp 10-SI alt. to a 105amp CS-130 in my 'Velle.
Thanks,
 

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"S" is the remote sense line. It's used to measure voltage down stream in the circuit and cause the regulator to control that point instead of the voltage off the back of the alternator. It is not needed for the CS alternator to function but is a nice feature. The attached link may be helpful or it may be too much information. See if that does it for you.
Wire gage is dependent on usage. I doubt you will be trying to pull 105 amps continualy out of the alternator.
http://www.alternatorparts.com/cs130_sbpage1.htm
 

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Discussion Starter #3
Okay...so if I understand correctly, the "S"-terminal is connected to a point in the vehicle harness to sense the voltage at that point. This then takes into account line-drop in the harness and doesn't simply measure the voltage coming directly out of the alternator. A few questions then: Where to sense the voltage? At the battery? Didn't GM run that wire to the horn relay? Seems like a long run of a wire just to sense voltage.
In that article it says that the "P"-terminal is connected to the tachometer. I know that we don't need this wire, but what is the purpose of the wire? I am a fan of making use of all that the alternator can accomplish. It seems like it must sense engine RPM so as to regulate duty-cycle. If this is correct, then it sounds like a good wire to hook-up as it would reduce parasitic drag. I think that the "F"-terminal can not be used unless we dream-up our own fault indicator to retro-fit in our older vehicles.

One last question: So how much current can be expected to flow through the battery wire? I understand that it is dependent on what electronics you have and how many are used at any one time, but if 105amps were used then this would require a 5AWG wire. An 8AWG can support only 54amps (if you assume 300 circular mils per amp for calculating power dissipation). If this is the case, why would anyone want or need a 105amp alternator if it is connected to the battery with only a 10 or 8AWG wire? Well, at least the wire is going to get hot and the insulation is going to get soft.
Just thinking while I type.
 

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"P" is used to drive an external device. If the car doesn't have something to drive, then "P" has no purpose.
If the battery is the point you want the circuit to monitor, then I guess that would be a good place to hook up the remote sense line. Remember these were used on never cars where the routing from the battery is different.
Upping the wire gage is a safety precaution. Think about what that wire between the alternator and battery is doing. It is providing power from the alternator to the battery. The battery hasn't changed. It will charge at the same rate as it did with the smaller alternator.
Your numbers on gage size assume all 105 amps will be using the same wire. Where's the extra current needed? If you load up the existing fuse box, with add on equipment, the existing wiring won't handle it.
 

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Discussion Starter #5
I see...so "P"-terminal is an output terminal used to drive an external electronic item. So you could drive your tach off of the signal as long as it was conditioned properly to operate with the tach.
It is true though that if you are putting out a steady 105amps then it is all going through that wire connected to the "Batt" terminal. Are you saying that this is not the case in the newer vehicles? I don't have a wiring diagram for this.

My very last question that pertains to this CS alternator is this: I bought an AC Delco 321-306 that is used in an '87 'Vette. The clocking and everything is identical to the stock DN alternator, but the upper bracket mount is not threaded for an 8mm bolt it is a thru-hole for an 8mm bolt. Is this a mistake or did I choose the one alternator that does not have that hole threaded? I don't really want to back-up this clamp bolt with a nut. That will make it a pain to adjust.
Thanks again for all of your help!
 

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The wiring out of the back of newer car alternators is not going to handle 105 amps continually. Nor is the car expected to draw 105 amps all the time. Alternator capacity and the car's requirements are two different things.
Can't answer your question on the lack of threads. Maybe someone else can. I have used nuts before when the threads were stripped. Just tightened up the pivot bolt first, then the nut and bolt on top.
 

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Discussion Starter #7
I know that it isn't going to put out 105amps continually, I was talking more theoretical. The idea that I was trying to get across is how the newer vehicles are wired to the alternator. Knowing the capacity of newer alternators, it seems that even an 8AWG wire might be a little inadequate if all of the charge is going through one wire. Now if you were to use say 3 10AWG's or 2 8AWG's then this is equivalent to 1 5AWG.

Anyways...anyone out there have any information about the non-threaded top-post of a CS-130?
 
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