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Damn, Alternator Not Enough?

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Old 08-13-04, 12:41 PM
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Damn, Alternator Not Enough?

I think Im loading my alternator too much. I have a Fiero GT Electric fan, a walbro reired fuel pump and a massive 2000watt stereo system with pre-amp and all. My battery slowly but surely dies out, even if my car is still on. My voltometer shows that when the stereo cranks and the a/c is on, it never goes past 11v on idle and while driving at around 12, If I really turn up my system it will reach almost 9v and shut off the radio by itself. Basically I have to have my foot on the gas pedal accelerating it to about 1.5k in order for it to not shut off. Its my alternator isnt it?
Old 08-13-04, 01:02 PM
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Sounds like you need more AMPs than the alternator can supply. Had that problem too. 100 AMP FD alternator solved that problem for me.

I was getting only 11.4V at idle and maybe 12.5V at cruise...not nearly enough to charge the battery. You should be seeing 13.8-14.4V or so, AFAIK.

Last edited by eViLRotor; 08-13-04 at 01:10 PM.
Old 08-13-04, 01:11 PM
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Turn all your loads off (including the fan) and check your voltage at the battery posts with the car running at idle (750 rpm's at least)...What do you get? Should be at least 14.4v...

I feel sorry for that poor little alternator...And your eardrums, lol

Note poor grounds could also cause your problems...
Old 08-13-04, 01:26 PM
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A regrounding and an FD alt upgrade is in order. I have not done the regrounding, but I have the FD alt with a perma cool 16" fan, 400W power inverter running my laptop and a wideband, and I see 14.4 at idle with the fan and the inverter running. At night, I see about 14.1 with the lights, defrost, radio, fan, and power inverter all going.
Old 08-13-04, 01:50 PM
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yea it definitly just sounds like your draining more power then what the alt can put back in the battery just get a fd alt and reground and that will solve it for sure
Old 08-13-04, 01:58 PM
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thanks everyone, Thats what Ill do. Any grounding writeups as to the key spots?
Old 08-13-04, 02:02 PM
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Originally Posted by MazdaRx7Racer4Life
thanks everyone, Thats what Ill do. Any grounding writeups as to the key spots?
https://www.rx7club.com/2nd-gen-archive-72/grounding-how-thorough-discriptive-199558/


That's the one in the archive, I pretty much followed it the way it shows to.
Old 08-13-04, 02:41 PM
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The stock piece of **** alternator cannot handle the load.
Grounding will not fix your problem.
These cars don't need to stinkin' 2000W stereo in them.
I get my audio fix revving the engine.

Get an FD alternator.
This is probably your easiest and quickest fix.


-Ted
Old 08-13-04, 04:55 PM
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Originally Posted by RETed
These cars don't need to stinkin' 2000W stereo in them.
I get my audio fix revving the engine.
!Amen to that!
Old 08-13-04, 04:57 PM
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Originally Posted by eViLRotor
!Amen to that!
My stereo includes and mp3 cd player and 2 rear stock speakers, no fronts
Old 08-14-04, 01:18 AM
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You may also want to get the fd alt. rewound for better performance since you have a big system in that 7.
Old 08-14-04, 01:24 AM
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Thats quite a strain you've got on your electrical system.

Yeah, these FD Alternator Alternators kick ***.
Old 08-14-04, 01:32 AM
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West TX RX-7 purchased an FD Alternator Kit from me. He couldn't have been more pleased. He needed it because he was running 2k watts rms on his stereo.
Old 08-15-04, 07:16 AM
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sounds great, how much are your alternator kits?
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