Unstable Voltage

[923000GT]

I have a 92 3000GT SL 5-Speed. I've noticed that whenever the RPMs are up (when in accelerating or in neutral) my voltage increases, my headlights get brighter, my AC runs higher, etc... I am aware that the alernator is turning faster and creating this increase. What's bothering me is, why do I get this better performance? Shouldn't my lights be as bright as they can be when I turn them on? and How can I stablize the voltage without buying a voltage stabilizer? I've tried that, and saw no difference. Any suggestions?

[AutostradaVR4]

what kind of voltage reading is the alternator putting out?

[Twizted_3KGT]

All the 3S's i've owned have done that, even with new alternator/battery. I accepted it as normal.

[923000GT]

It fluctuates from just under 12V up to as much as 14V.

[youngvr4]

in my experience its usually a early sign of the alternator or battery slowly getting weaker

but, it may very well be a normal thing also. i have to check, i dont pay much attention to that

[923000GT]

Thanks, I just put in a new Optima. I'll get my alternator checked.

[talskinyguy]

If you have an underdrive pully this is normal, if not your alternator may be on the way out, but it may last years in its current condition. 12-14v is normal, under 12 is a little low, but mine used to do the same thing.