Join Date: Jan 2004
Location: Winston Salem, NC
My question is does a 78 amp alternator always put out 78 amps or only if that much juice is required?
I ask because I just did an upgrade. After much research on MAD electrical, here and other places I planned to upgrade to a 10si. They are typically 63 amp and do not require you to change out the charge wire in the system.
Good news/bad news. I buy my 10si from Autozone and there is a 12si in the box! A sheet of paper says that they have consolidated the part number and the 12si is all they use. That is great because I got a more modern, higher output alternator for the price of a 10si ($44.95).
The problem is that it is a 78 amp unit so now I am worried about my factory wiring. It is 10 ga. from the alternator to the buss bar and 10 from the buss bar to the core support junction. I have read mixed reviews with some saying upgrade it to 8 ga. and others saying 8 ga. is only needed with 94 amp alternators.
My electrical needs are fairly small with a 9 amp draw for the fuel pump and about 10 amp for the electric fan I have. So does that mean the alternator won't be putting out full amperage and I should be ok?
What do you think?
69 Camaro, 3650lbs., 400ci, TH400, Coan 10" converter, 3.50 gear
D1SC, pump gas, 9:1, 10 PSI, Water/Meth injection
1.325 60', 5.988 @ 115.4 (carb)
Switched to Super Sniper EFI 2019