I agree its not they way it should work.
My 95 when new did not have low voltage at idle. Until the Alternator went south. After a few rebuilts and research I discovered the CS130's voltage regulator was
modified to temperature compensate. Thus lowering the voltage at idle. And Im sure they may have increased the size of the pully. As for the newer alternator, (I forget the model) there are 2 fans to help the problem. But I see it still exists. These problem all stem from the fact the the alternator are small in size, with no where for the heat to go.
Tips: Dont get a rebuilt alternator, go to the dealer. The newer units have the up to date fixes. Although they use voltage regulators that have been pulled.
The best voltage regulator (cs130) I found was made by USI Universal Scientific Industrial Co. 71-10011HD. I believe there is a new cross for the number. DMOS output for the Field allows for a higher Amp output, and a higher voltage at idle. Most pulls dont give good regulation of voltage at idle. And yes GM does use pulls in new alts.
Measure your pulley before you trade a bad one in!
Yes, if you need low rpm power you'll need a larger alternator. I believe the next size is 130A, but it requires new brackets.
The days of Delta Wye change are long gone.
BTW if anyone has tried the 'Iceberg' CS130 let us know. Its supposed to be 120A with a modified bearing/rectifier carrier.

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