My open diff failed on me last year after 2 years of AutoX and I've been looking for an LSD unit with no real luck (a few bites, but difficulties from the supplier made it a nightmare).

I have a Miata parts car with a Torsen Diff sitting in the garage. When I spoke with the guy's over at Kaaz, they stated that their Miata Diff would work in the N/A FC so I'm curious if the Torsen diff will also work.

If so, what would I need to do the swap? Should I swap the internals only or the entire housing?

 

they do have a stock N/A LSD for the FC.
You just haven't been looking in the right places.
For the price of a Kaaz you could go to a full TII Driveline swap,again if you shop Thrifty.

 

The Torsen diff will fit in the FC. They are both 7" diffs (T2 are 8")

You have to take the ring gear off of the Miata Torsen, and put the FC ring gear on so that it still matches the pinion. Only the 1.8 Torsen works.

oh look what I found googling "miata diff in n/a fc"

https://www.rx7club.com/2nd-gen-arch...ousing-229115/

 

I looked through local Car forums and Mazda Clubs, Ebay, Craigslist etc. I could find aftermarket units, but I could never find used units. I think I even looked here once or twice.

Thanks and just because you've found it when I obviously haven't, doesn't mean I haven't tried. I've been looking for nearly 7-8 months now for a diff for my FC, so I'm a little frustrated and unsure of how to word my searches. Whenever I did look into the torsen diff swapp all I ever managed to find was how to swap an FC TII diff into the 1.8 Miata's.

 

The S4 NA came with a clutch type LSD option.

 

^ Yes. And S5 is viscous something...not sure of the term.

What year car? I have an S4 LSD for years (from styx - he posted above), lol, haven't gotten around to putting it in, not really planning on selling, but someone remind me what they go for lol.

OP, post a WTB (wanted to buy) thread in your regional section here:

NE For Sale/ Wanted/ Classifieds - RX7Club.com

 

Got to agree with Paulo..
For ***** and giggle I looked at your posts and didn't see one Inquiry or WTB thread for your part.
Nobody would know you want one if you don't ask.
I bought one for 150 Bucks..like 2 days after I bought a car with an open diff,so they are readily available..
..and it was Found on this Forum.

The Miata thread Link above doesn't work for pics..the Forum was revamped and material was lost.

 

an fd lsd works as well. it is torsen type too. from what i've gathered, torsen are better suited for auto x, while clutch are better for drifting. and viscous coupling is not favorable for either. clutch types are typically stronger, but being clutches, do wear. torsen engages instantaneously, but not as strong as clutch.
i had an na with miata torsen. now i have an s4 t2. i preferred the torsen, but i think my clutches are worn. doubt they've ever been serviced. it doesn't engage nearly as quick as the na did

 

An Fd lsd would work in a TII, not a N/A. Ring gears are different sizes between turbo and n/a cars.

 

hmm. could have sworn i'd read somewhere that it was a viable option for the na rear end. maybe i was mistaken

 

Try my page:
Triple-R: FC3S Buildup - Chapter 2: Part 17

NA and T2/FD pumpkins are not interchangeable.

Regards,
Crispy