Rx-7 Alternator Cross Reference and Swap Chart

v- Chassis swap notes ->	alternator	bolt in	circuit rewire *	change pulley	Comments
'81-'85 (50A Alternator, SE: 60A)	50A	X			LR Charging system diagram
	60A	X			LR
	70A	X			LR
	80A		X		"L-S" diagram
	100A		X	X	LS
'86-'88 (70A alternator)	70A	X			LR
	80A		X		LS
	100A		X	X	LS
'89-'92 (80A alternator)	80A	X			'91 Charging system diagram
	100A			X	Mystery switch on '91 alt. lamp.
'93 & up (100A alternator)	100A	X			LS

General Observations:
I've had some feedback from a couple of people. Seems there are some variations in the current ratings. I can only assume this is a result of running production changes by Mazda or their suppliers...

Pictures of various alternators

1st gen, N221 50A	GSL-SE, N304 60A © David Lane	'86-'88 NA, N326 70A
'91 NA, N350 80A © David Lane	'91 Turbo, N370 80A	3rd gen, N3A1 100A
'89 & up connector

* Requires alternator circuit rewire. When installing an LS alternator (S5 or S6) into an earlier car (S2-S4) you will need to do more than just change the connector. Based on the wiring diagrams comparisons and other information resources that I agree with, I have come to the following conclusions:

Diodes will not correctly solve the problem.
Relays will not correctly solve the problem.
The LS type alternator requires a constant power reference on the S (sense?) line.

Diagrams:

To convert an LR system to an LS system you must change the "R" circuit to an "S" circuit by moving the wire connected to the alternator to a constant battery reference. If you don't feel comfortable doing this I would recommend sticking with a "plug compatible" alternator or have a shop rebuild yours for more current.

To modify the wiring based on the wiring diagrams above:

Disconnect the battery ground cable.
Change the alternator plug on the engine harness: WB to WB (White/Black trace). Tape the BW (Black/White trace) wire on the engine harness.
Connect the WL (White/Blue trace) on the new alternator connector to an appropriately fused (15A-30A), +12V source. Preferably the fusible link block or equivalent.
Connect the battery ground cable.

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Disclaimer: I take no responsibility for the accuracy of this information or electrical damage that may result from improper wiring.

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$Date: 2005/09/02 18:48:16 $