(ELECTRICAL) "Economical" Alternator Upgrade
 

OK, here's the latest of what I have found after doing this conversion three times in various year's chassis. For those wanting to ditch the 50/55 amp alternator in your 1stgen, this is probably the cheapest way to kick up to an 80 amp alternator which should be plenty unless you've got a TON of stuff and you run it at max ALL the time...

First up, the universal wiring diagram reference...

https://www.rx7club.com//attachment....postid=2310730

For the TII alt plug, I've seen two different wire colors, but I think the yellow w/blue stripe and white w/green stripe combo may have been a conversion harness leftover itself. Underneath is a quicky reference to all the different color combos I've seen in the various chassis and the physical rlationship of the different plugs...early style on bottom. Just match your colors and you'll get it right. I need to state again that the 1979 part had already been converted to the later style charging system and the external regulator was eliminated. Since the car is gone, I really am not sure what is involved making the conversion, but these are how the wires in the engine bay harness attached to the TII alt when I replaced the old alternator originally installed by Rotary Performance.

This is the actual install in the 1980 chassis...

https://www.rx7club.com//attachment....postid=2302517

Going from the top green arrow clockwise...

• The '89/'91 TII plug itself which you must have gotten with the alternator to make this happen.
• Tiny bit of the blue stripe on the yellow wire from the TII alt plug....the second TII alternator I got for the '83 had simply yellow and white wires with no stripes at all.
• White wire w/black stripe...note that this particular wire's color scheme seems to be the same regardless of year...looking at the Haynes, you wouldn't think it so, but neither of the swapped alternators ever burned out.
• 8 ga. wire going to the fusible link box on the strut tower of the '80...it never, ever gave me any problems with this routing, I might add.

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

https://www.rx7club.com//attachment....postid=2302538

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

https://www.rx7club.com//attachment....postid=2302569

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....postid=2310730


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 di find out that normal male/female couplers will go on perfectly!

my tII alt dropped directly in, without any washers... i just had to keep the big spacer in there... and i didn't have to mess with the wiring:)

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.

Rx-7 Alternator Cross Reference and Swap Chart
 

Triggered by the ongoing thread about alternators on the 1st gen list, I put together this page using my collection of parts and Rx-7s as reference...

If you have any feedback, please let me know.

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

enjoy,
John

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.

Rx-4 & REPU alts...
 

Before anybody changes an alternator on an Rx-4 or REPU just because it has an external regulator...

A long time ago I "upgraded" the alternator on my Rx-4 to an alternator with an IC regualtor (came with the "low mileage" Jap. engine). Because of a reply I got about the alternator swap page, I happened to check the FSM on the Rx-4. It turns out that the Rx-4 had a 63A alternator. Guess changing the alternator may not have been an upgrade after all! :eek:

Excellent reference... I have one thing to add.
namely, about he problem with Battery drain, and needing a relay. You don't need the C&C relay just a diode, wired in like I described above.

Without a diode, built into the C&C relay or by itself the field coil will remain slightly powered when you turn the car off. This will slowly drain down the battery. The voltage drop accross the diode is all it needs to almost completely turn the coil off.

The drain may continue, but at a lower rate (I'd guess around 3-4 weeks to drain). I personally perfer to just remove the battery from the circuit if I think I'm going to let it sit that long, but if it still bothers you add a resistor. Adding a small resistance (say 10-100 ohm, 1 Watt) inline with the diode will make it even less of a problem (a couple months min drain). Just make sure that the resistance isn't so high that the alternator won't turn on.

Thanks fatboy, This is the information I wanted :)

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:

I was looking at the '81 wiring and don't understand the source of the power drain some people are seeing. Both wires going to the alternator connector are switched... compared to the newer models that only seem switch the L terminal...

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...postid=2642045


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...postid=2642060


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:

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...
https://i7.ebayimg.com/02/i/01/52/e8/55_1_b.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.

i would go for dankus's buik alternator conversion
130 watts wasnt it?"

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.

And it only costs $40 total, right? Remember the name of the thread...economical...and if you do junkyard shopping, read the metal tag! All 2ndgen alternators are not the same! Caveat Emptor...;)

Just checked the alternator that came on my jspec t2 motor and it says 70 Amp?

where are the local junk yards that sell rx7 parts??

there are 2 walk in junkyards in sun valley (u-pick u-pull OR pick-up part). located 5 Fwy and tuxford exit.

there are other locations too and it depends if your willing to drive up there. im heading tomorrow or saturday morning. send me pm if your interested.

lol....listen to what I'm saying...there are minor differences in all the alternators offered in the RX-7s....calling it TII is convenient, but calling it the 80 amp model is specific and the '89 -'91 S5 alternator will say it right on the tag....you have to look or be told specifically it is an 80 amp model to know you got the right one...assume nothing...except that the conversion work I've laid out for y'all is correct...;)

i just put an fd alt in my 84 gsl-se and it went in without much problem. had to grind some clearance on the v pulley that i robbed from a mototech alt my neighbor had laying around in his barn.
otherwise hookup and install went flawlessly

when i wired up my fd alt in my 84 i just used the hot wire i had left over from my air pump removal for the extra 12 volt wire the alt needs.
when the car is turned on the alt gets the extra 12v it needs otherwise not. maybe this hookup will cure the batt drain prob.
give me a few days and i will let you know if all is still well.

anybody have the link for the silicone vaccumn tubing for the great price?
i know it was in one of these alt threads but it is like a needle in a haystack to me right now
thanks

http://www.hightempsilicone.com

thanks

So what difference did you see with the alternator change??

actually not much running wise other than my alt/amp gauge always reads at a higher level and never goes below half now at idle.
i am running about 800 watts of amps, a black magic electric fan and the electric 6 port mod on the system so far.
with the cost of the used off ebay 100amp alt and any other expenses(wire/terminals), i have under 60.00 in this mod.
not bad i think

my next mod will be one of those 7 point engine ground setups i see mazdaspeed sells.
they say it will improve performance.
i will keep everyone posted