Alternator and voltage regulator question?

On a '94 DAK 3.7ltr AT, AC cc is the alternator's out put controlled by the computer or is there an independent voltage regulator? Also: my truck came with the 90A alternator, can I upgrade to the 120A HD alternator without causing problems in whatever acts as the voltage regulator?

TIA. Bill

Reply to
Diamond Dave
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1) internal to the engine comp 2) no idea

Reply to
Gary Glaenzer

The regulator won't care what amp alternator is installed, it only deals with regulating the voltage.

Be sure your wires are properly sized for the added current.

Reply to
John Kunkel

Yea, but it does it by controlling the current to the field windings. If this new alternators field winding current exceeds the capabilities of the computer internal regulator, it could damage it.

Reply to
TBone

Yea, I was thinking the same thing. If your going to be pulling more current out of the alternator, you'll need more current on the field winding, to supply it.

If you truly are going to be drawing more current, you may want to consider an external regulator.

Reply to
Nirodac

Is there a different CPU for the vehicles with the 120A alternator and opposed to the ones with the 90A? Have you ever heard of defining which CPU to get by what alternator you have? I'm not going with a monster aftermarket alternator, just the bigger 120A one that was optional on this truck.

Reply to
Diamond Dave

I have no idea if a different computer was used for the 120A alternator but if it was an option, probably not. There may however been other changes such as the wiring harness connecting the alternator to the vehicle. I guess the first question you need to ask is why you want or need the 120A to begin with.

Reply to
TBone

The computer supplies a variable ground for one side of the field, the current in the field doesn't rise with the alternator's output; several different alternator amp ratings are controlled by the same computer.

Reply to
John Kunkel

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