Yeah,I hear you.It would be a bad time to install an alternator, just to have it burn up an ecu or such. Time to look for the RX7 piece. I might still do the wires though. Thanks, Payam , for the input.

I'm also about to do the "big three" wire upgrade as I've swapped out the stock battery for a larger one.

why would an alternator burn up an ECU and such?

Improperly regulated?

--Ian

Westfield burnt up an ecu a few years back using the ms3 alternator control. I have not heard of any other instances

yeah but that's regulation issues, not additional amperage issues. That's always a concern regardless of the alternator used.

I was thinking about regulation . Maybe it is a long shot, but it is an ebay alternator. When I did a search on them, they had both good and some bad reviews

Sorry to bump an old thread, but I'm failing in my googles.

What year/model is the Kia alternator from? I can't figure it out. The 95-97 Sephia alternator seemed like a logical choice to search for since it's the same engine, but those seem to be 70 amp units.

Help? I need a manly alternator.

Google image search matched up the Kia alt image with one from here.
https://uedata.amazon.com/DB-Electri.../dp/B007Y85D0S
98-01 Sephia, 70 amp.

A bit of amazon search found this similar one.
99-01 Sephia, 110 amp.

Both are new and not reman. Rockauto has a bunch of new 99 Sephia alternators too. Now to find out if they fit.

http://revlimiter.net/blog/wp-conten...8/DSC_3006.jpg


For future info...The FD alternator is from a 1.3L 93-95 (in the US) Mazda RX-7. 100 amps, 5 groove pulley. 2 wire terminal that plugs into the NA socket and the same size hot post.
The Kia alternator is from a 99-01 1.8L Kia Sephia or a 00-04 Kia Spectra. It claims to be a 110 amp unit and has a 4 groove pulley same as the NA. 2 wire terminal and a tiny hot post.

http://revlimiter.net/blog/wp-conten...8/DSC_3037.jpg

http://revlimiter.net/blog/wp-conten...8/DSC_3040.jpg

The Kia alt needs some grinding in order for it to fit on the BP. The lower mounting tab needs some meat taken out of that support. It also needs the upper mounting tab drilled through to allow it to work on the stock tensioner.

http://revlimiter.net/blog/wp-conten...8/DSC_3058.jpg
The Kia unit I got was new, not reman. And it sucked. It couldn't hold voltage steady for anything when cold and when hot it could only manage 12.8 volts output. The engine would nearly die at idle when the fans turned on. My old stock alt did better than that. And I'd hacked it up, so I couldn't return it.

http://revlimiter.net/blog/wp-conten...8/DSC_3047.jpg
The FD alt needed a few bits sliced out in order for it to get more tensioner range. It wouldn't get too close to the block without these bits removed.

http://revlimiter.net/blog/wp-conten...8/DSC_3191.jpg
It works great though. Great voltage and good regulation. No bad behavior at idle when the fans kick on. Not bad for a remanufactured Mitsubishi alt.

I took a bunch more pix and wrote a blog post about this. Hope it helps some folks in the future.
Non-Stock Alternators That Fit Miatas ? revlimiter.net

Yep, I had to remove the same bits to get it to get the belt on, also swapped the pulley.
I started researching the Toyota Sienna 150 amp alternator. It looks like it could fit, but never actually got hands on it.

I never had to grind anything down for the FD alternator to fit. You're right it doesn't get as close to the block as stock, but it doesn't interfere when the belt is under tension so increasing the range in the wrong direction seems a bit moot. If it's a simple matter of getting the belt on, I think I just unbolted my waterpump pulley and set belts on the alternator first.

All I have seen is FD alt into NA cars, what is required to use FD alt in my NB with MS3 (Rev)?
I blew an alternator a while back and through in a old used on I have laying around, that one didn't last long and didn't put out enough power to fire the plugs at boost so I am thinking the extra amperage will help. Now I don't trust my car and want to get this issue sorted out. Thanks in advance for your help!

Same physical mods, and then follow the instructions posted somewhere around here to swap an NA alt into an NB, electrically. FM has a write up that's been posted here a few times. :)

FD has an internal regulator like a NA. What concealer said.

Hi everyone, sorry to bump this thread but I can't seem to find an answer...

I am installing the FD alt and unfortunately it appears that mine will require the physical modifications that some of you had to do (grind the casing).

I found a thread on M.net where someone used a larger belt instead of modifying the casing. The belt they used was a Dayco 5040350.

So I'm wondering if there's an advantage to using the stock Miata belt and modifying the alt vs. using the larger belt?

Thanks!

There would be an advantage to the belt solution. Buy the belt and report back . You will need to use a straight edge to make sure there is no offset in the alt pulley compared to the other pulleys the belt rotates upon.

Thanks for the recommendation! Thinking of buying the Bando version of the belt.

​I'm curious what your rationale is for using the larger belt compared to grinding the housing as most posts I've seen do. Personally I'm leaning towards the larger belt, but curious as to why it seems most people prefer to grind the housing and use the stock Miata belt.

A good reason to grind it would be that you already have a belt that will work.

A good reason not to grind it would be that if you ever have to replace it with minimal tools you won't be totally fucked. Also warranty.

Howdy all! Just reporting back.

I cross referenced the Dayco belt and bought the Bando equivalent (4PK890). It seems to fit well. We'll see how it works when I get the motor in.

I also used a M10-1.25 x 110 bolt to attach the lower mounting point. I found that a 100 bolt was short and didn't thread all the way through the mount.

I didn't grind anything down and everything appears to be lined up.

https://cimg7.ibsrv.net/gimg/www.mia...09abd96f3a.jpg