Just figured I'd let everyone know that Advanced Auto actually sells a 70Amp direct replacement for 65Amp alternators of the 86-87.5 Rx7's. I know it's not an FD 100Amp, but it's still nice for those that do not have the time to redo their harnesses.

 

Any GM 180 Degree bolt hole alternator with an internal regulator will work as well. You will have to modify your V-belt pulley to fit in most cases. I used a 140 Amp out of a 1993 Oldsmobile once.


Just thought I'd add that.

 

They make a 70 amp alt, because that is what came from the factory on that car.

All S4 models, had a 70 amp alt, while S5 models had a 80 amp alt.

65 amp alts were only on the 84-85 models.

If you notice in the 86 and 87 brochures (both found in the what did my car come with sticky thread at the top of this section) that under electrical, a 70 amp alternator is clearly called for and described.

 

Good to know. Do you need to alter the wiring harness at all?
Oh my fault Icemark. I was under the impression it was 65. They do sell two versions for the 86-87.5 though. One is 65 amps, the other 70.