My 7's alternator broke and I needed a new one. My local auto parts store didn't carry the rx7 alt anymore but they had a rx8 alt in stock. Last month I changed the tstat on my rx8 and noticed that the alternators look similar. After getting it home I realized that the shafts were different sizes.

I drilled out my pulley and made a custom spacer out of a pipe fitting.
I Grinded the threads off first and then cut the fitting to get a straight cut.
The rx8 uses the pcm as a voltage regulator but the e8 works as a voltage regulator.
(for all the non haltech guys, maybe you can get a aftermarket volt reg from summit?)
I used pwm3 and hooked it up.
Its working fine. I've never been able to roll the windows up with the efan on and the headlights and the heat on high. Make sure you cover the battery positive with something really strong. unless you want to start a fire in your car.
goodluck guys, heres some pics.(the pic of the voltmeter was the first test)

 

holy crap, 16.1 volts? better regulate that baby down a tad


cool idea tho. I wonder if my E6K could regulate that as well

 

yeah that high voltage was the first test before I messed with the mazda alternator settings. Its in the pwm menu in the e8 software.

 

I am wondering about this for a TII on the PS1000....
Yo,Chris!(C Ludwig)..can ya chime in?

 

The Sport ECUs have alternator control. I've done a couple Miatas with the Sport and it's worked great. In that application anyway, voltage really never varies. You get a very slight dip when you turn lights and such on but the alternator and ECU react very quickly and do a great job of maintaining whatever voltage you program.

 

So,does anyone know if the shaft size on the rx8 alternator is the same as an FD alternator?
Fc is 15mm,Fd is 17mm.

 

not sure but i did similar with fd alt on my first gen.... haven't had it running yet. am I going to have issues or is the voltage regulated in the fd alt? or though the pcm as well?

 

FD alt is still internally regulated

 

Suweet

 

Nice job on the retrofit Lupin, looks clean and effective.

One thing I would like to point out to anyone attempting to perform this is that the benefits aren't exactly worth the effort over a FD alternator. Both the FD and FE S1 alternators put out the same 100 amps just like the JC Cosmo does. However, the main benefit to the FE Alternator conversion is that the FE S2 one puts out 110 Amps and is controlled by a PWM signal from the ECU exactly like the FE S1 Alternator. With some clever electronics work, one can simulate this signal using cheap hardware from Ebay to adjust the voltage regulator to your specific needs, saving an output on your Haltech.

Or you could just visit the junkyard and grab a 130A Taurus Alternator for $20. Not knocking your work or anything as I've got mad respect for those who think outside the box and come up with clever solutions like this. I just think that there's a simpler, cheaper way of getting the job done.

 

Did anyone find an answer to this? My voltage bounces around on my car. I already did the FD update so if I could just throw in the RX8 alt that would be sweet.

 

[QUOTE=Akagis_white_comet;11380970Both the FD and FE S1 alternators put out the same 100 amps just like the JC Cosmo does. [/QUOTE]

Actually, the JC Cosmo(13BRE) comes with a 90amp alternator.

 

Anyone have a print out of their alternator settings? Wondering how to get this going on a megasquirt board for the pwm settings.