Welp, I just got around to taking care of this.
Special thanx goes out to silverrotor for putting together this kit!
I jumped on the bandwagon kinda late, but after seeing that he wasn't going to be selling them anymore, I quickly shot the PayPal payment through.

Here's my take on the swap...

1) The FD alternator original "B" terminal goes too close to the stock TMIC. (Yes, I still run one!) :P My fix? I took off the FD unit and swapped the FC one. You just need to grind down the "divot" that helps the FC unit stay in place, but since the post is splined, this is really unnecessary. I was able to mount the FC unit on the FD alternator after figuring out which angle the splines engaged and cleared the TMIC - mines ended up pointing very close to the alternator plug. This also allowed me to keep the smaller closed-end connector on the wiring harness and bolted right back on - no cutting, splicing, or replacing the stock +B connector.

2) Using the supplied FD alternator plug in the kit, I crimped on a male spade terminal. I pulled out the correct wire lead off the FC wiring harness and just plugged it in. I just left the rest of the wiring intact, just in case I needed to go back to an S4 alternator.

3) I was a bit worried about the constant +12VDC wiring, since it wasn't fused. I temporarily wired it to my front circuit breaker. So far so good - I was a bit worried about excess drain, but the battery voltage looked good after sitting overnight.

4) Mounting on the S4 was a snap. You need to the spacer, but you can get rid of the rear nut on the lower mounting point; the FD alternator has a built in rear nut. The other side bracket was a little more involved - you need to find a longer bolt and nut (or did I miss something???) and thread them straight through. Even if I used a 10mm diameter thread (14mm head bolt), it would not fit through the stock bracket adjustment slot - so I just dug around for a longer bolt (8mm thread diameter, 12mm bolt head) and a nut (plus lock washer) to secure the alternator. I got the included double pulley, and that made putting the belts back on a snap. I've heard of people having trouble with a small "bump" on the alternator, but it wasn't a big deal for me.

So how does it perform?
Keep in mind I was using an S4 alternator with a Racing Beat double pulley (underdrive).
I was tired watching the voltage drop under 12.0VDC, especially at night.

HOLY SHIAT!
Those other testimonials weren't joking!
I'm still kicking myself for not doing this sooner!

Idle, no lights - before ~13.5, after ~13.75
Revved, no lights - before ~13.75, after ~13.9
Idle, electric fan on - before ~12.2, after ~13.5 (DRAMATIC)
Idle, headlights on - before ~11.5, after ~12.5
Revved, headlights on - before ~12.0, after ~13.5 (DRAMATIC)

Now, absolute worse case...
Idle, headlights on, electric fan on, step on brake pedal -
before ~11.0, after ~12.5 (DRAMATIC)

Voltmeter is a VDO 2-1/16" unit.

Once the engine revs came up, voltage drop even with big power drains don't seem to phase it.
All my lights are noticably brighter, and my headlights are also brighter at night.
My poor battery used to take a beating driving around at night, and after sitting overnight, it would barely read over ~11.0VDC prior to cranking.
Now, the same battery sit easily over 12.0VDC under the same conditions.

Side note, I bypassed my Boost-A-Pump to try and track down my low-voltage problem to my fuel pump, and it didn't do jack.
Even with the FD alternator in there, it's still running mostly at around 8.0VDC.
I even switched voltmeters from the HKS 46mm to another (verified working) VDO voltmeter, and it still all reads low.
So it looks like the stock wiring is CRAP; after redoing the relay up front at the fuel pump resistor system, I should've known this. :P

I dunno what Mazda was thinking when they went with the stock alternator, but the FD alternator upgrade a no brainer.
The only downside is the price.


-Ted

 

damn i wish i could get one, i need it badly.

 

Is there a point to getting one with just an underdriven main pulley?

Thanks Ted.

 

Ted you have pics of this divit you are talking about? Great write up BTW

 

As far as divoting the IC, its not necessary. You can loosen and move the B+ line out of the way of the IC and then retighten (the plastic peice). No divot needed.

Right now I am chasing the battery drain. I know there is an issue but I am not sure what the source is, but I know that if I have to park the car overnight I have to disconnect the wiring harness from the alt (not the B+ line). I run a Hawker battery and it just cant stand up to that kind of drain. I think I am going to put a relay in line and run it that way.. Any thoughts?

 

Great write up, Im definately considering this. Pics would be nice. Thanks!

 

I need to pickup another, but I need the damn 6rib pulley with it, no more vbelts for me!

 

too much hassle, I'm gonna take my alt to a local shop and get it upgraded. That's what my buddy smoken' did

 

A little more background on the battery drain:

Its approximately 1/4 amp (measured with an inline ammeter) of drain that goes away when the connector (Sense and Field) are disconnected. I remember reading a LONG time ago that there was an electrical difference between the FC alt and the FD alt that had something to do with the relay for the "Field" wire. Either way, I have isolated the wire and I plan to put an auxilliary relay on this wire so when ignition is off it shuts this wire down.

Rat

 

what do you mean upgraded?

what kinda places do such a thing and does it really work well?

how much would it cost?

 

Ive got a question: Since the FD alt needs a wire going to a 12v source, why not attach it to the B+ connector (thats the wire you tighten down on the alt with the nut right?). Im looking for the image but I thought the B+ connector draws 12v of current. Although I ran a wire directly to the battery, I was just wondering if this could be done without screwing my electrical crap up.

 

I think it would be better to have the 12v constant wire from the battery/fuse panel on the tower so that the voltage regulator can adjust the voltage that the battery gets/sees. I'm thinking of trying to run a wire from the fuel pump to the alt voltage regulator to see what I get, just a little experiment.

The FD alt is a great uprgrade for the overburden FC electical system!

 

Hey Ted, you are quite welcome man...It took long enough to here from you. I'm glad you are enjoying your new Investment. Mazda skimped on an Inferior Alt that has plaqued us FC owners for sometime now - unless one upgrades their Alternator.

 

Splice in a blocking diode with the white/black wire just before the alternator connector. Done. Cost? About a buck or one out of the trash bin.

What alternator are you running???? Series five or four?

******* I plan to put an auxilliary relay on this wire so when ignition is off it shuts this wire down.********************************************* ***

Diodes cheaper and quicker.

 

I am running an FD alternator.. But how is the diode going to work? I need to block the 12 volts from the source (field) wire when the car is off. This isnt a feedback issue its the fact that the alternator field is still being powered!

 

Never mind. I thought you were using the original series four wiring. It sounds like that isn't the case.

 

Bad Hailers, no doughnut..

 

I got a fd alt also from silverrotor and it works great and it was nice to see more power at night and enough power for my sound system to go in...I'd recomend doing this upgrade.

 

i also bought an alternator from silverrotor...but now my problem is that in the morning when i crank her over....my apexi turbo timer/voltage reads 14.5-15V

 

i'd like to upgrade to a fd alternator. but no one is selling the kit anymore?

 

I have seen that too, but that Apexi voltmeter seems to be horribly inaccurate.

 

I'm curious. I don't have a FD alternator. So I ask, you have one wire from the *S* terminal going straight to the battery (maybe fused) and the other wire, the *L* terminal, going to the relay in the CPU (series four car)?

OR?

 

OR:

I used the stock harness and soldered in an FD style plug! No muss no fuss!

 

There's a shop around here that does alternator and starter rebuilds and they charge $150 to bump it up to like 120 amps. I haven't gotten it done yet, but my buddy Smoken' got his s4 alternator rebuilt at a different shop where he lives and it was around $150 I think. They replace the components of the alternator with higher output stuff. I bet if you looked in the phone book there is some place that does alternator rebuilds near you.

 

Do the Black/White wire and White/Black still route as they did before? Or put another way, do they still go where they went when the car was built. The ends other than the ones at the alternator?