i have been told that a cheap and easy upgrade for us 1st gen-ers is the S4 T2 alternator. its a quick bolt-on upgrade because its got the same connections as our stock alternators. my question is, how can you tell if its a S4 T2 unit? are there serial numbers that tell you? is there something i should be looking for? i actually bought one and i want to make sure im getting what i asked for. thanks in advance.

hoang

 

How about you post the part number on the alternator up here (or Google it yourself) and see what pops up? As for looking for anything special, I can't really think of anything. Serial numbers and part numbers will vary based on brand. There is no difference between an S4 TII or S4 NA alternator as far as I can tell. Good luck!
-John

 

^^^ NA and T2 alternators are the same EXCEPT for the positioning of the electrical connectors.

T2 connectors are in a slightly different position as they had to clear the top mount intercooler in stock form.


As for whether they bolt up, plug in, and work on a first gen - I don't know.

 

S4 Alt's have the same wiring as the 1st gens, and a S5 will work as well but needs a small wiring change

 

An S4 series is only a 70amp capable unit. It can be modified with a bosch stator to put out roughly 100 amps but will suffer at idle.

S5 and S6 are very similar internally. Both are factory 85 amp units. The S5 can be upgraded to a 120 amp while the S6 can go up to 200 amp.

S4, S5, S6 all are clocked the same way and can bolt on in place of the other with miner modification.

I recommend finding a S6 unit and having it built to the 140 amp version. Your idle speed won’t suffer and you will have more power to work with.

Hope that helps answer your question.

 

S6 also has a larger shaft size so your pulley won't fit without machining.

Can't use the S6 pulley because it is a serpentine type and not V-belt.

 

thanks everyone. this is very helpful info. now i am contemplating upgrading to a S5 or S6 since the modifications are minimal. thanks again guys.

hoang

 

Yes, they do. This Duralast Alternator 14716 (autozone.com) drop'd in easily.

A couple minor notes:

1)The threaded portion of the pulley shaft is shorter and the shoulder of the shaft is taller than the OEM, so if you're using anything other than a V-belt there might be issues.

2) The ground post at the top is too fat (the OEM eyelet is for a post that a 8mm nut threads onto), HOWEVER- the round black cap at the back snaps on/off easily and hidden underneath it is a threaded post just like what is needed for the OEM eyelet! -I notched the side of it to allow the eyelet to seat properly, then snapped the cap back on. I'll eventually either cut that post down til it's flush with the cap OR remove it completely and stack some washers under for the proper stand-off (don't forget some rubber washers to isolate it)

 

Since this thread got pulled from the dead, here's more detail with pics and drawings and mention of the problem with this T2 alternator swap.

https://www.rx7club.com/1st-generati...pgrade-239526/

Mario III

 

Lordy, the last post hints at it but I never finished the thread. Just wiring in the alternator will present a slow drain on the battery. If the car sits too long w/o being started, the alternator will drain the battery dead. That relay seen in the last post was set up in my FB chassis wiring loom to connect the offending "draining" wire ONLY when the key was in the "On" position....and that solved the problem completely.