If our 79 RX7 came witha 50 amp alternator and a 1987 (70 amp) FC alternator is a direct bolt in replacement, what is the downside with having a higher amperage alternator on the car? Is the wiring in the elctrical system made for a 50 amp alternator or does it not matter?

We replaced the battery this summer along with the alternator but car drops to 10 1/2 volts when trying to start on a cold morning. Not enough juice. I don't like having to either slow chagre the battery or jump start it.

Thanks for you advice.

 

On the stock 3-wire prong, use a test light to find juice to provide power to the FB or FC alternator. Again, you will only use 1 wire; the rest, you dont need.

 

No this alternator is not a bolt in job. The voltage regulator on SA'a is external and it's internal on an FC. This complicates the problem immensely. I have an FD alt for my SA but it's not in yet so I ahven't worked out how to do the swap yet. Other than that, the extra amps will only help and your electrical system will be fine with the higher capacity. By spring, I'll get this figured out and I'll post what I did then. Or maybe someone will post the electrical mods necessary and help us both out.

 

This doesn't help with the '79, but for those doing other alternator upgrades, this is a good site:

http://www.rx7.org/public/altxref.html

Rich

 

So should I look for a 60 amp alternator that would bolt in to the 79? Or am I stuck with the 50 amp?

 

THATS BS. How do you think Im able to drive around in my RX-3 with FC alternator.

 

https://www.rx7club.com/1st-gen-archive-71/electrical-83-alt-79-a-369140/