JFD_8126

iTrader: (5)

Hey all,

I havent been on rx7 club in a while since i sold my FD, but recently i have purchased a miata shell and am wanting to a FD swap. I am only concerned about what differential i should use? I already have purchased my full FD swap with tranny, but to make the job simpler, the TII will bolt right up instead of modifying my chassis for a FD differential. Please help me out guys.

Thanks!

fendamonky

iTrader: (6)

Yes, the T2 diff should handle the power. I believe it is actually considered more solid then the stock FD diff.

JBarron

iTrader: (8)

The LSD unit is at least. It's a clutch type which is going to be stronger than the FD's torsen.As far as the gears themselves I'm not sure, but the TII LSD bolts to the FD ring gear and can be swapped into a FD housing.

DriftDreamzSS

iTrader: (4)

the S4 TII clutch type will be better for any driveline shock like drag launches or clutch kicks for drifting, thats what breaks the FD torsens. They usually hold up fine at high power levels otherwise. I believe the S5 TII is viscous type so you should probably stay away from that as old vlsd's are often worn out and dont lock very hard.

blkops

mine sounds like there is a spoon stuck in it. the TII dif is what ill be using. as far as ive read its more solid.

probably easier to find.. and cheaper as well.

JFD_8126

iTrader: (5)

Thank you I appreciate all the responses. Hopefully I can get one. Is there anyway to determine if it is a s4 type differential?

NoPis10

iTrader: (29)

Here are some helpful pics. It was very hard for me to find a TII diff as there were NO pics around to compare. After 3 tries it was accomplished.


S4 N/A diff is on the left, S4 TII diff middle, S5 TII diff on right.

JFD_8126

iTrader: (5)

Thanks. The picture was really helpful. One last question, I know that the TII Differential housing is way longer than the miata Differential housing, and i will be using the FD tranny. The distance from the end of the tranny to differential will be shorter. Now i know i will be going custom Driveshaft, but since the distance is short, will a shorter driveshaft be a problem for me? Like will it break or cannot withstand stock FD hp.

thanks

MiniRob

Your doing the same swap as me. Mines a 91 miata, its off at the paint shop right now and this week ill be picking up the 13b rew engine and trans this week. You doing all the fab work yourself? I want to keep in touch because ill be making it up as i go along and any help would be usefull.

blkops

use the Fd dif housing with tII dif

JFD_8126

iTrader: (5)

Im glad there are more people that will be doing this swap as well. Yes, i will be doing the fabrication myself, but have little experience in doing fab work. During the time of this project, i will be going to school for this stuff.

The reason why i want to use the TII diff housing is because it bolts right up to my chassis. Just need to modify the ppf. If i will be using the FD diff, more fabrication will be needed which im trying to avoid.

Keep in touch with me MiniRob. Im always there to help and hopefully get help as well from people reading my posts. Really Grateful.

MiniRob, have you figured out your setup yet? Please let me know what you plan on doing.

Just to be more clear, im not really talking about the internals of the differential housing, im talking about the differential housing itself. Whatever that will help me avoid extreme modification. I have already read that the TII differential housing will bolt right up to my chassis.

My only concern is that i will be using the FD tranny and the TII Differential. I know i will have to create a custom Driveshaft for this and i know it will get shorter because of the distance from the FD tranny to the TII Housing.

Will i be taking a risk doing this such as......
Horsepower loss?
More Prone for a driveshaft to break?
Shorter Driveshaft are not good and what reasons?
(Driveshafts guys driveshafts lol)

thanks a bunch guys. Feels good to be back in the rx7 world.

MiniRob

Im sure the length shouldnt be a problem with the drive shaft. What axles work with the TII diff?

JFD_8126

iTrader: (5)

I was reading you can use the tii axles but u got to use the tii wheel hubs as well. I'm not to sure about that , but I want to give that a try. Solomiata.com has some helpful tips on what are interchangeable between rx7s and miatas

BryanDowns

iTrader: (2)

I did this to my old miata many years ago.

The "wings" on the TII differential will bolt into the miata so long as you use miata "wing" bushings. Wont work with the TII bushings. The bushings are interchangable, you just have to knock out the TII ones and knock the miata ones in.

This gets it hanging in there for you however there is nothing to hold the front in place. I made a front mount by welding some stuff to my rear subframe. Note that when you put the TII diff at a good angle you will be mere inches from the gas tank due to the length of the TII nose.

You can use the TII axles, they are about the same length. I used them. You'll have to do something about getting the splines of the TII axles to work with the miata hubs. I got some TII hubs and had them machined down correctly to fit into the miata upright. I believe most others have done that. The only others I've heard about had their stock miata hubs resplined. I suppose either way will work.

In a miata I highly doubt you break any of this. I was running 11 flat in the 1/4 and pulling 1.5 60fts in my miata without hurting stock TII axles or the stock TII diff one bit. I used to bounce off the limited building boost then dump the 6 puck clutch on slicks for those 1.5 60fts.
http://www.youtube.com/watch?v=NCn2bxl0tDE

The rest was 4 cylinder powered, but I dont think you have any worries about the TII stuff in the miata so long as you get it all working correctly. I would be more worried about whatever engineering you do getting it mounted than the parts themselves.

JFD_8126

iTrader: (5)

Damn bro. Your motivating me now lol. What did u do with the ppf??? Or it's just pretty much trial and error? I'm so siked for this

BryanDowns

iTrader: (2)

Eliminated the PPF entirely. Created a mount for the front of the diff. I also created a transmission mount that spanned the tranny tunnel.

Big power will very likely break the miata PPF. Especially after you cut / weld on it.