esmith972

Forgive me, for I am dumb. Stock '85 GS

If there are NO loads on the alternator (radio, A/C and lights), the car is fine; pretty much the moment I put a load on the alt, the car runs like crap and the tach goes all wacky.

Fortunately, I have and know how to use a voltmeter. The running voltage is 13.5 and with loads it's 12. Hell, with the blinkers going, my dash dims. Video below.

Forward James!

Is this due to our poor, puny little, stinking, idiotic, imbecile 55amp alternators? If so, you are the weakest link, goodbye. No but seriously, if that is true, what is a good upgrade that is direct bolt on with no wiring modifications?

My cup runneth over. Thank you, thank you, thank you. *bows forth*

http://video.google.com/videoplay?do...15299119&hl=en

djessence

If the alt is problem, best bet is second gen alternator tho a tiny bit of modification is required. you *might* be able to get a high output alternator from a alt shop but i doubt it.

Are they 55amp alternators, i thought they were like 35?

Sgt.Stinkfist

iTrader: (6)

yeah tha alt. could be goin, but nows is a good time to make sure you grounds arent all dirty and corroded. if you buy a 2nd gen alt., i believe the 70amp S4 alt. is a direct bolt on/plug in, and the S5 80amp will bolt on but needs a little wiring

dj55b

iTrader: (2)

Yes our alternator are 55Amp, and S4 rx7 alternator is an upgrade and you will need the big spacer that is found on the alternator. There is no real modifications to the, it just a direct plug in. THey're also rated at a much higher 80Amps. THe S5 will need rewiring thought if you wish to go that route, i think they had a few more Amps in there too but don't quote me on that.

Sam

Sgt.Stinkfist

iTrader: (6)

^ha, beat ya to it

waysrx7

Buy this https://www.rx7club.com/showthread.php?t=745800 it'll solve your power needs.

bliffle

The OEM alt is perfectly OK.

You have a corroded connection either at the battery or at the ground connection fo the battery. get a $4 ID/OD wirebrush cleaner for the posts and clamps at your local autostore.

esmith972

It is *most* definitely the alternator.

I drove/sped/drifted (:P) to work and ran a battery and altenator test. It has a 302mV ripple (which is excessive as stated by the tester) with 12.27V without loads and 11.50V with loads. Below is a picture I drew on MSPaint of the little graph it printed out.

Now my question is, what the heck causes a voltage ripple?

Sgt.Stinkfist

iTrader: (6)

a bad diode in the alternator... bad alternator