Hey all,
I'm swapping a FD torsen into my TII's diff case, along with a 4.3 ring and pinion from racing beat. I'm letting a transmission shop take care of this, but I'm wondering if there's anything else besides the RB ring and pinion and the FD torsen unit that I might need to give the shop to complete the project. Any items that should be replaced while it's open? Thanks in advance!

Steve

 

I'd probably do the bearings at the same time

 

Should I be getting the FD ring and pinion from Racing Beat? or the TII ring and pinion?

Steve

 

FD Ring and pinion prolly wont fit. (I dont actually know, I'm just guessing)

Definitely replace the bearings.
New seals wouldnt be a bad idea either

The shop will need stuff like a crush sleeve (tube) and (reccomended) a new lock nut for the front. (Not because the old one is nessisarily bad, but because the best way to get the thing out involves destroying the old one )

 

You will need the TII ring & pinion gear set. Esenntially, the shop will swapping the gear cases (i.e., VLSD and Torson). They will need to adjust the pinion, depth using selectable washers, since you're changing the R&P from 4.1 to 4.3. Perhaps you should consider changing the bearings too. There are 2 side bearings and 3 pinion bearings in the rear end. You'll need to replace the 3 oil seals, the collapsable spacer (which is used to adjust pinion bearing preload), and the pinion flange nut (recommended by Mazda). Adjusting pinion depth, pinion bearing preload, and backlash are critical. Proper adjustments will provide long lifetime and a quite riding rear end. Be sure to do a proper break-in of the new R&P...drive the car for about 3 or 4 thirty minute periods at moderate speeds (non-highway), and let the rear end cool down between each period. After 300 miles change the diff oil...you may want to put in a good synthetic, but use petroleum based as the break-in oil.

You may also want to change the speedo gear assembly in your tranny since the new R&P will cause a slight speedometer error (i.e., 3 mph).

BTW, where did you get the Torson drive unit? I'd like to put one of these in my 90 GXL if I pickup one for a good price.

Hot_Dog
90 RX7 GXL
02 Acura RSX-S

 

Thanks for the informative posts guys! I picked up the torsen unit from an FD, it won't fit the NA drivetrain(7" vs. 8") but you CAN grab one from a miata and have it installed. Search "miata torsen" and you'll find a whole bunch of threads.

My car was a GTUs, so I've already got a 4.3 speedo gear in there. It's reading off right now. Thanks again!

Steve

 

Anyone finding "good deals" on these Miata Torsens? Pretty much everything on Ebay seems to be going for $300+. I suppose in the end that's decent, but . . . .

 

we fitted first FD torsen into our european TII open diff case today, fits ok
just gotta have it adjusted and put into Phoenix's car...

 

Good choice. The feel of the torsen is awesome, very fast & smooth lock up.

 

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

 

curious.? what year of miata have that so called famous "miata torsen"..?? i'll got look for some for my gtu.. which is sorry and doens't have one..but what year of miata come with the "miata torsen".?? and MtnRacer, you say that the fd unit doesn't fit the na drivetrain.?..

1990_whitecomet

 

94-current miatas have torsens if they had limited slip.

the 94+ miata and the na fc (84-85 rx7 too) have the same diff/ring gear size

the turbo rx7's are larger

mike

 

sweet.. so its the 94+ miata huh.. kOol.. and the na fc 84-85.? the sb you mean.? do that have it also.? any model.? or just some.?

1990_whitecomet

 

Note, not EVERY 94+ miata had LSD though... but if it had LSD you can be assured that it was a torsen (at least that what I understand).

Pre 94 was just a VLSD if I understand correctly.