FC diff help ....
 

Hey starting to get pretty bored of my open diff on my fc & am hoping for some help for you lovely boys & girls who can assist.

What are my options...

-welded diff? whats it like to live with as a daily driver?

-aftermarket lsd to fit in a n/a housing? expensive & hard to come by?

-mx5 diff & housing? havn't been able to find much info on this at all, but reakon its is the safest & most cost effect best bet?

-T!! diff & housing? Possible?? if so i take it i would need the shafts that go to te hubs of a T!! as well?

any help would be great thank you James?

No one able to help???

It's great, as long as you never, ever have to turn.

kaaz makes one. It is in the high hundreds IIRC.

Custom driveshaft or take the shaft, trans, flywheel/clutch/front counterweight off a TII.

This info refers to US cars, I don't know about outside the US: Some S4 GXLs had clutch type LSDs, but many of them are all worn out by now. Rebuilding them is expensive from what I've seen. The S5 GTUs (not the GTU) came with a viscus LSD that will swap right in. For either of these you'll need the half shafts that came with the specific carrier.

A Miata torsen will fit.

Clutch type LSDs were offered in 86-88 GXL models, and 88 GTU model.

I have a clutch type LSD in my car from an 88 GTU.

It is only a few hundred bucks to fully rebuild these diffs. It is by far the cheapest solution if you get one that is burned up.

miata, kaaz, GXL, GTUs or turbo II rear end swap. those are about the most common swaps.

don't go with a welded diff unless you live in a trailer park in alabama and have a wrecking yard nearby with plenty of rx7 rearend parts. i say that because it puts alot of stress on the rear axles even driving normally when taking turns and you will look like a redneck or ricer with your tires barking going around turns. do it right or don't do it at all, seen too many people try to do things the cheap way to only be stuck on the side of the road. besides the options are fairly cheap, just about as much work and cost as it is to drop the diff, open it up and have the gears welded professionally.

did i mention it's also a safety hazard if the welds break or a piece of metal does come free and siezes the gears? if you do weld it just please only drive the car on the track.

only weld it if its a drift only car.

My friends 240 got his welded and so far its been over 2 years and its holding up fine through many drift events. I dont know how good it is to compare the two rear ends of 240s and rx7s but a proper welded diff wont break, its mostly halfshafts, or the stubs lol.
Also, driving in the rain...it is a pain in the ass trying to not drift every corner. You have to baby it around corners.

Best bet if you want lsd is to get a S4 GXL lsd, cheap and fairly cheap to rebuild.

http://rx7.com/store/rx7/fcdrivetrain_rearend.html
Kaaz for n/a diffs

i think its rare but i think mazda came out with a na lsd dif

It's not rare, the GXL has a limited slip diff.

Thanks for your help guys, is a great help as we speak am trying to source a torsen lsd out of mx5/miata seems to be going well have my eye on one or two will let you know soon, thanks again!

In anyone is interested i have found out that a n/a fc diff housing can take a miata/mx5 diff, you wanna find a 98+ miata (mk2 or 2.5) that came with aircon, abs & a 3 spoke steering wheel this will be a an is model that they made all these came with a Torsen lsd which are interchangable with the n/a housing.