a buddy of mine has a very low mileage FD differential (10k miles) and he will sell it to me pretty cheap (~100 bucks) i currently have a series4 TII clutchtype diff in my car, but the clutch packs are worn.

my question is, is the FD torsen diff a straightup swap with the TII diffs?

 

yes

http://rx7cz.net/photos/workshop56/

 

Just make sure all settings are within spec and you're good to go.

 

Hey hiGGi,

When you swapped the LSD, what were the things that needed to replaced?

I am about to do this swap soon.

Thanks.

 

front and side seals

 

Yes, it is a direct swap. I made a writeup on swapping a torsen LSD from a miata into a N/A Diff when I did it. Complete with pictures and all.:

https://www.rx7club.com/showthread.p...hreadid=229115

Youll need to properly adjust the backlash, and those processes are at the end of chapter 9 of the FSM. Youll ideally want a differential stand, and youll need a dial indicator.

On a side note though, why do you want to do this? You realize FD guys swap in S4 turbo clutch type LSDs, because they are stronger, and lock up just as fast. (unless worn, of course).Although if you have a S5 viscous LSD.. it would be a worthwhile swap.

 

Hey hiGGi,

When you swapped the LSD, what were the things that needed to replaced?

I am about to do this swap soon.

Thanks.

 

seals, front and sides

 

rxm is right...FD guys swap in S4 TII LSDs for drag racing cuz they have a better lockup rate and hold more power. Are you using this car for drag racing? or normal driving? The viscous LSD's are way better for use in road racing, so depending on what you want to use the car for, the fd LSD might not be the best choice...good luck with the swap though!

neil

 

You're right about the clutch types ability to hold more power under drag launches but what do you mean it has a better lockup rate?

The torsen differential has the fastest lock up times because its actuation is fundamentally different from a clutch types, reacting before slip even occurs.

And why is viscous best for road racing? It reacts the slowest of the three types mentioned. IMO, best for road racing goes to torsen or clutch type.

 

i suppose i could just get some new clutch packs for my S4 diff.. the diff still locks, but i dont know about the condition of it (unknown miles, etc) it still locks up though.

 

See how much a local shop would charge to swap them out for you (+ the price of the Torsen), then compare that to how much it would cost to rebuild your clutch type LSD+labor. Remember you could end up getting your money back selling yout clutch LSD also. Im not knocking the torsen, its a good LSD for sure, but like I said, the clutch is stronger. How much power are you looking to make? If you have the money, Id look into aftermarket clutch LSDs, or clutch pack upgrades for the stock one. I hear aftermarket clutch types are really awesome.

 

Stock Zenki turbo LSD is most likely worn and needs to be rebuilt to work properly.  At the very least, you can get oversized plates for a more aggressive lock.  You're looking at $300 just in parts!

Ni5mo180SX is right - Torsen reacts faster, typically.  The clutch-type LSD doesn't really do anything until it hits it's lock-up point, which is typically more slippage than a Torsen.

http://fc3spro.com/TECH/MODS/DT/lsd.htm


-Ted

 

anyone know how much parts are (s4 TII) for stock lockup? i was thinking 100 bucks or so, but i dont really know.

 

I think you need 8 plates at about $35/ plate from mazdatrix.

 

yea, my bad. i was thinking of something else...sorry.. but i was talking about the torsen diffs are better for road racing because of the predictability aspect.

 

I just swapped in the FD torsen along with the Toe eliminator bushings.
Car handles alot different during cornering. It's alot more stable on the limit and has more overall grip when cornering.