Z31 rear conversion

[CamInHead]

From S12Silvia.com;

Originally Posted by Draconis

Did you get the Z31 bits from a Turbo option? They are a bit different. I used an NA MKII rear, which is the same as the S12 but for the hub for the vented rear disc.

I've half a mind to try fitting the 6-bolt flange to the z31 arm and useing the S12 driveshafts

[CamInHead]

Yay panic over lol. The driveshaft flange is indeed interchangeable and fits the outer flange perfectly. I'll chuck pctures up later.

[s13eater]

Originally Posted by CamInHead

Yay panic over lol. The driveshaft flange is indeed interchangeable and fits the outer flange perfectly. I'll chuck pctures up later.

good on ya matey,mine will have to be done later in the year.

[CamInHead]

[Draconis]

Yeah, as far as I knew all Z31 Turbo's had a form of LSD. The late Turbos, MKII, had a clutch-type differential while the MKI I think had a viscous type.

In addition, my understanding, the turbo diff also has different splines in the axle. So if you go that route, the turbo Z31 axles are required.

I currently have my stock open differential with the NA MKII rear end. Because the NA MKII rear end is basically the same as the S12, the only difference is that the hub allows for a vented rear disc. It was literally plug and play. I dropped down my stock S12 rear and bolted up the Z31 NA MKII rear end. The bolts all matched up, the brake lines had to be slightly massaged for clearance spacing on the hub (not much at all) and the Z31 axles bolted right in. For this reason and simplicity, I suggest this route.

Turbo is ideal but has the possibility of containing more issues.

[CamInHead]

I imagine after 20 years they're likely all slipping like fook anyway. I was keen to keep the stock s12 axles/driveshafts so I could potentially upgrade to an S13/14 based LSD later.

[s13eater]

Originally Posted by CamInHead

I imagine after 20 years they're likely all slipping like fook anyway. I was keen to keep the stock s12 axles/driveshafts so I could potentially upgrade to an S13/14 based LSD later.

yeah, thats what i was planing, i've got the s13 lsvd in mine, so at a later date i could go with a machanical one.

[CamInHead]

I set about compairing my two rear beams today.


-Turbo S12 Mk2 top, Z31 turbo lower. Using various mounting points as datum points they're identical to within +/- 5mm.

I offered up my Z31 arms to the S12 beam and they line-up spot-on. TBH I'm not sure if the arms are turbo or N/A, but they're 5-stud;









BEHOLD my brush painted arms!

I then offered-up the Z31 beam to my S12. I didn't fancy fitting my bushes to the beam incase I culdn't get them out again lol so this was a very rough mock-up;




I won't be using the Z31 beam as the machine work done to it is sloppy as fook but otherwise I see no reason why it wouldn't match up.

[s13eater]

spot on, i din't think they would be different,good on ya for letting us know,

[Draconis]

You are doing what I should have done. Very well done indeed. Mind if I use this in one of my write ups by chance?