Alternator output - Team Camaro Tech
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post #1 of 5 (permalink) Old Mar 26th, 10, 09:20 AM Thread Starter
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Greg
 
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Alternator output

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
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post #2 of 5 (permalink) Old Mar 26th, 10, 10:04 AM
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Re: Alternator output

Alternator only puts out what is demanded. Ten gauge will be fine, might run a 8 AWG to the buss bar from the alt and run the fan power from the buss bar.

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post #3 of 5 (permalink) Old Mar 26th, 10, 11:10 AM
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Re: Alternator output

Quote:
Originally Posted by Everett#2390 View Post
Alternator only puts out what is demanded. Ten gauge will be fine, might run a 8 AWG to the buss bar from the alt and run the fan power from the buss bar.
And Greg, there's nothing to add.
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post #4 of 5 (permalink) Old Mar 26th, 10, 02:13 PM
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Re: Alternator output

Thank you, Fred.

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post #5 of 5 (permalink) Old Mar 27th, 10, 07:55 AM Thread Starter
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Greg
 
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Re: Alternator output

Thanks guys. That is what I was hoping to hear. I have seen that you can take the original 10 AWG alternator wire and move it to the core support junction. That gives you 2 10AWG wires from the buss over to the junction for added capacity.

Then you run 8AWG from the alternator to the buss bar as Everett mentioned. I may end up doing this "just in case".

I do already have the fan relay pulling power from the buss bar. Don't have the fuel pump there though because it is in the back and the battery is in the trunk. I just routed the relay main power to the battery as it was only 2' away vs about 12' to the buss bar.

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
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