wrankin

I've been looking at my options about putting an LSD into my NA FC (currently has an open diff). I have seen several comments that the Honda S2000 torsen units will fit into the 7-inch rear.

Has anyone actually done this operation, or directly know someone who has?

Thanks,

-b

drftwerks

iTrader: (1)

try it, be the first.

SirCygnus

iTrader: (1)

get a spare rear end from each car and try it out man.

how stout are the honda rear ends?

wrankin

Yeah, I would just hate to buy it and find it doesn't fit - I would be left with yet another box of unused car parts in the garage.

-b

sunburn

Why not just put the TII rear in? fairly cheap, bolts in and can handle more power then you'll ever make NA

junito1

I would say void the honda crap.

My LSd wore out on my TII- SO i bought a used TII S4(clutch type LSD)

ProBLEM SOLVED ANd they are rebuildable.=D

wrankin

Car will eventually (hopefully) find it's way towards SCCA ITS Club Racing. Rules require that you keep the stock diff carrier, but you can swap in any internals. Top contenders are the Miata Torsen or the S4 clutch-type LSD. If the S2000 is an equivalent unit, then it gives me another place to look.


-bill

freemanrx7

It is the weak link in the s2000 drivetrain. Alos the trans from 2000-03.

TitaniumTT

why not skip the guess work and just get a Miata torsen and be done with it? I would venture to say that S2000 parts are more expensive than Miata parts even if they are the identical unit

wrankin

I've been hunting around for the Miata Torsen, but it seems all the Miata guys are grabbing them up as upgrades for their existing open diffs. The prices aren't dropping significantly. All the S2000s had the LSD from the factory, so the demand from the other owners seems to be less since there are no open diff models to upgrade. There seems to be more of them sitting around.

Most of the Miata examples I have seen are $400+. Couldn't find any decent deals.

-b

Turbo II Rotor

iTrader: (2)

I believe the diff will swap over. Go for it.

Don49

iTrader: (3)

Kahren has a Miata torsen listed in the 2nd gen for sale section-$400 shipped.

Bruceman

iTrader: (5)

What about a LSD unit from a large axle FB?
My understanding is that they also fit. Well I understand they fit in the Miata and therefore must fit the FC.

Turbo II Rotor

iTrader: (2)

FB doesn't have a torsen which is what the OP wants to swap in. I'm sure he'd just install a S4 NA LSD if he wanted one.

Icemark

Hmm I thought the S2000 uses the Mazda 8 inch torsen differential assembly right out of a FD, FE and Sportage.

This is the first time I have ever heard that it was a 7 inch unit, and if so, I guess you would still have to use the FD/FE pinion shafts.

S2000 diff:

wrankin

From this article:

http://www.turbomagazine.com/tech/08...ech/index.html

It appears that the S2000 uses the 7" rear end. They do not indicate for sure if the pumpkins are swappable, but they seem to imply so. So hopefully it would be a matter of changing out the ring and pinion to the stock FC unit, just like swapping in a Miata Torsen.

I am just trying to avoid being the guinea pig here.

-b

TurboII RudeBoy

i read that article a while back it's , what i was thinking about is they mention the rx8 also , and icemark is right it's 8 inches in those applications .my thoughts are they will fit 8 inch cars ie t2 fd fe. down here in s fla alot of s2k boys run fd diffs when they break theirs as a cheap alternative.

rnz520

iTrader: (10)

DO NOT use an S2000 diff, they are weak and not cheap, just use the mazda unit from the Miata or buy an aftermarket unit.

TitaniumTT

There's your answer I guess. N/A's are 7" rears so you're stuck with the miata rear.

wrankin

Yeah, the article is somewhat confusing. They do say outright that it is a 7-inch rear end in the text, but in their comparison of final drive ratios they cite both the 94-97 Miata (7-inch rear) as well as the RX-8 (8-inch rear) *and* the 79-82 RX-7 (7-inch rear). So I don't think that table is meant to be an indication of where you can get parts from.

If they are using the FD diff as a replacement, is there any chance that they use the entire casing? I guess I'll go poke around on some the S2k forums.

Thanks,

-bill

wrankin

Okay, it looks like the S2000 runs a 7-inch rear where the ring and pinions are sourced from Mazda. The torsen unit uses thicker stub shafts and is not compatible with the Miata unit (and thus is not compatible with the NA FC) at least not without some fabrication work.

This comes from the page:

http://members.aol.com/solomiata/Drivetrain.html

Note that AOL has dropped these pages and so you will have to go to http://www.archive.org/ and plug in the above URL to see the original contents.

-bill

TurboII RudeBoy

interesting ... 7 inch ring gear like an n/a and i guess the torsen must be the same as the fd.

wrankin

No, because if it were the same as the FD, then it would require an 8-inch ring-gear. It is a 7-inch rear end.

I would think that the only way it would work would be if there is enough room in the S2K carrier to hold the 8-inch pumpkin and the FD pinion would fit, which is a possibility. Or they are swapping out the entire carrier and fabbing up a mounting bracket.