Niaxe

Hello fellow forum dwellers! I have 2002 SE Miata with ~ 42k miles and it seems like my alternator died. Had no crank on Friday, charged the battery and it fired up. Drove it for 15 miles and after the drive checked with multimeter battery's voltage. I believe it jumped to 14.00v for a second and then dropped to 12-13 and alternator wasn't doing anything. Checked for parasitic draw and it was ~ 0.15 amps or so, pulled fuses too and the car doesn't seem to draw more than 20 amps when idling. Battery is brand new and checked at AutoZone, seems good and healthy.

Now an important point - last week I had a shop install and tune Haltech Elite 1500 on the car. They noted that alternator was acting a bit strange, but at that point it was still working. I've heard that haltech's voltage regulation of NBs alternators is kind of junky, does it still remain true?

Which route should I go?

1) Get NA8 Alternator
2) Get NB Alternator
3) Get FD Alternator

I like the idea of NA8 IR alternator, but I am kind of concerned about splicing the wiring (I am not sure if the procedure/instructions would be different because of Haltech and I have no clue how the shop wired it). Another concern is that 60 amp alternator might not be enough for this car. I have SPAL fans, kenwood single din radio, Aeromotive 340lph fuel pump (flex fuel), bigger injectors, etc. Tuner thought that NA alternator should be plenty, but SPAL fans alone are usually 25-30 amps right? Add to that headlights, AC and so on and it seems like a big load. Also, if I do go NB alternator route, would I need to retune it in Haltech or should it be just PNP?

Any words of advice good people?

rwyatt365

FWIW I've been using a FD alternator (albeit, with an MS). The only issue I had was that the field exciter would not "turn on" until the first time the engine revved above 1500 RPM. I solved that by wiring up 12V through a switch in the cockpit to the field exciter circuit on the alternator, That way, after key-on, I would flip the switch, turn on the field and hey-presto, the FD alternator put out 15V immediately.

As always, YMMV

Niaxe

I see, thanks. I've heard that some people reported that FD alternators take 3-5 seconds to kick in, but this one is new. Thanks, I'll take a note of that!