Charging system

[89revival]

I have a question about the charging system on an 89gt. When the car is at idle the battery voltage drops to about 11.8 volts, it doesn't really go any lower than that even with the blower on, lights, wipers etc. When I crack the throttle it charges at 14volts. The battery gauge needle shows just barely above the red at idle. It is a new battery, but its a NAPA battery. Normal?

 

[wildponies]

what size alternator do you have?

 

[89revival]

stock, I believe its a 75amp

 

[wildponies]

Bump it up...I just put a powermaster single cable 140amp in....worked wonders for me..

 

[svtnotch]

Do you have underdrive pulleys? Mine was doing the same thing. I just put 3g from 95 stang in mine problem fixed.

 

[89revival]

It does have underdrive pulleys

 

[AdirondackFox08]

Maybe this will help. http://www.allfordmustangs.com/Detailed/72.shtml

 

[89revival]

Thanks for all the help, I will upgrade the alternator. Didn't even think about the pulleys.