"Economical" Alternator Upgrade
 

The actual shot of the fusible link attachment as physical proof I did it that way in the '80...

https://www.rx7club.com/attachment.p...1&d=1216784321

This is the actual install into the 83 chassis...

https://www.rx7club.com/attachment.p...1&d=1216784860

For this install, I decided to completely take apart the plug of the TII alternator I picked up and run the '83 wires directly into the TII plug's metal spades...a lot of frustrating work because of the small size of everything, but the result is a completely factory look...the wire on the output pedestal this time goes directly to the battery, which is the method favored by Rotary Performance as evidenced in them doing just that to the long gone '79...

Actually bolting in the '89/'91 TII alternator into the 1stgen chassis is the easiest part.

• Just unbolt your old alternator and keep all the fasteners and related clips, if any...
• Buy 5 or 6 standard size flat washers like you'll find at Home Depot that will just fit on the alternator bolt itself.
• Use masking tape to hold that pack of washers together...trust me on this one...;)
• Physically place the TII alternator into the mount, run the long bolt in and stuff your washer pack as shown in the diagram below and tighten.

https://www.rx7club.com/attachment.p...1&d=1216786144


Done...the pulley doesn't need to be changed and it will work with your old belt, too, although this would be a real good time to put on a new one, right?:D

Thanks, nice work!

I'd cover up the + alt output wire's connectors since they're hot.

Damn you got mad drawing skills!

Awesome Mario! I was just asked someone about the wiring diagram to do this swap and this looks very well done. Is the TII plug somewhat of an easy to find connector at, say, an autoparts store? Just wondering, 'cause I didn't get it with the 80-A alt. Thanks.

actually mine just broke, but I did find out that normal male/female couplers will go on perfectly!

what are you doing with the wiring for the original external regulator when you are using a alternator with a built-in regulator in a SA?

Your diagram reminds me of that book for type 1 Volkswagon that's called something like "Hows to keep your Volkswagon alive for the complete idiot" or something like that. Great work!

Thanks, guys for the compliments on the sketches...all hand done for your viewing pleasure...I love stipple drawings...

The '79 that was converted was done by Rotary Performance of Garland, TX. I never looked to see what they did with the leftover wiring, but the regulator itself was gone. That particular car has since faded into the mists of history after taking down a utility pole late one rainy night on Cooper St....:cool:

i was in NOPI's main warehouse friday and saw that book on the wall in there show room..... they started out as a v.w. parts place now they mainly do rice converions :)

...and i have a FEW friends that want to know how the hell you can jump or bypass the ext. reg. on rotary stuff...rx2,3 100 and repu... so if anybody knows PLEASE shead some light on this.:)

if you did the upgrade to a higher rating alternator, why do you still have the stock fusible links? Or am I missing something.

I think I can.

You need some type of regulator. So first off, you need an FB alt, or something more exotic like Mario is showing here, the S5 style.

Then you have to make a decision, do you need the dummy light? If not then its really easy, if so, you need to get a choke & check relay from an FB.

If you eliminate the dummy light than all you need is a diode. if you keep the dummy light, then just wire in the choke and check relay's coil/diode in the orientation the diode would be, then wire in the NC (normally closed), NO (normally open) parts to the dummy light, and choke switch respectively.

Now for the good stuff:
1. Remove the alternator, and external regulator.
2. Install new alternator, using washers like shown by Mario above if necessary.
3. Grab the BLg (from key switch, ON and start) wire that went to the regulator and route it over to the alternator (or choke and check and add a wire from there to the alt).
4. Connect the BLg wire to both the anode of the diode(the side the arrow points away from, no white band on real diode) and to the BW wire coming from the ’83 alt (Y or WL if S5) .
5. Connect the Cathode of the diode (the side the arrow points to, the side with the white bar on a real diode) to the WB wire coming from the ’83 alt (W or WG if S5).
6. Start the car, and check the system voltage, to be sure the alternator is now working.

That’s it, your done… remove unnecessary wires and clean up.

Refer to Mario's wonderful drawing above, he did a good job, and it may be helpful for color comparison for different years.

The point is that the fusible box will work fine with the bigger amp alternator and does not need to be "upgraded" if you don't want to mess with it.:cool:

Yea I've had my 80 amp alt in there for over a year on stock fuseable links and it works fine.

The wires are the same for an '84....here is an S5 80 amp alt into an '84 chassis I did this past weekend...this time, I chose to simply solder in the leads and shrink-wrap them since I'm selling red rex to a local buyer in May...

This first one is the pedestal clamp that makes in-car soldering a joy, seen holding the S5 plug and a bit of the '84s wire...

https://www.rx7club.com/attachment.p...1&d=1216175953


And then the completed install with a little rubber cap to make DriveFast7 a happy camper this time around...;)

https://www.rx7club.com/attachment.p...1&d=1216175953


One thing I should add....make sure you get a ring end that fits the S5 alternator's output pedestal before you start, so you'll have everything right there when you do the upgrade. The stock output wire from the chassis harness will have to be cut to length for the "new" alternator as it is way too long.

This alternator was off of eBay for $40.50 total, so this is the cheapest one I've done so far....and yes, I know, one day I'll clean the freakin' engine bay...:p:


:cool:

S5 alternators
 

regarding the S5 TII alternator, is it the same as the S4 or S5 all motor (n/a) alternator??? great write up btw, mar3

thanks in advance, :)

-Ray-

The NA alternators are anywhere from 50 to 65 amp output models...that's why you're looking for a TII car...if someone is advertising or listing an S4 or S5 alternator, always make sure it's an 80 amp model before bidding or buying one. The metal tag on the alternator will have its amp rating clearly on it.:cool:

I gots me a 91 turbo alternator...
http://www.rx7.org/jes/images/DSCN1193(1024).jpg

....The stock ring up top was too small for the bolt it attaches too, so I just cut it, bent it out, and fastened it tight under the nut.

The plastic harness is different, so it was busted open, and the 2 wires with spade connectors slip right on. Works great.

Last week I upgraded my 74 REPU 50 amp generator and external regulator to a S4 88 Rx7 n/a 70 amp alternator with built in regulator.

Bolted right up. Used four thick washers instead of spacer. REPU spacer won't fit, too long. Biggest trick was wiring up the exciter wire. Take the six pin external regulator connector. The one that's wired into the harness. Flip it up so it's connectors are looking up at you. Bottom rightmost wire gets wired into the alternator. It gets +12 volts with ignition switch ON or START.

On the alternator, where the the two wire pigtail goes: Wire it into the top, horizontal connector on the alternator. I am not using the lower vertical connector at all.

The Generator dash idiot light works correctly too. With motor off and ignition switch to ON, G light is on. With motor running G light is off!

And I got rid of that ugly external regulator.

14.38 volts @ alternator. 14.36 volts @ battery + terminal!!!!!!!!!! Only .02 volt drop thru the 11 foot REPU + alt cable! I replaced the stock 10 gauge alt wire with thickly sleeved 6 gauge.

There's not much electrical components on the old school rotaries so 70 amps will be PLEANTY. At most I'll add a 100 watt stereo or some nice 80 watt headlights.

Plus the S4 88 n/a 70 amp alternator was in stock for $106.00. The S5 90 T][ 80 amp alternator was in Indiana for $168.

less than 50$? Dude, I've gotta do this. And don't worry about your engine bay, it's cleaner than mine is, and I *have* been cleaning it!

Jon

junkyards here in socal are packed with MX-6, 2nd gens, and other mazda that have same alternators. $15 with 30 days warranty. In my experience with imports, I will only get the green coil pack. other colors are bought from autozone pep-boys etc which are known for failure. yes, they come with lifetime warranty but how many times would you need to change it.

If you do junkyard shopping, read the metal tag! All 2ndgen alternators are not the same! Caveat Emptor...;)