Hey anyone done or have information as to how to fit R31 Skyline rear disc setup? Any help would be appreciated. I've seen a few past posts and some say its an easier conversion than b/bird rear drum over disc setup. Thanks!

yes. we have done that conversion but not fitted to a 1200 datto sorry

it would be straight forward to adapt
it fits our cortina

Ive got some model of skyline rear disks on my datto pretty sure they are R31 but they were added when I changed the diff to a LSD borgwarner 28 spline I think these are in V8 commondores and some skylines also the cheepest way to do it would be to go to "pick and pay more" get ya self a skyline diff and brakes and get someone to shorten and mount it.

Or ya could always buy one new like I did it was expensive but well worth it, it's proably the strongest part of my car.

Just something about the R31 skyline diffs, if you do decide to get one shortened to suit + retain the discs + stud pattern for the 1200..

The Pintara R31, which is the CA20E 4 cylinder model, has only got a 2 pinion centre with smaller axles (lower spline count), whereas the six cylinder R31 skylines - the skyline runs the same basic 4 pinion, 28 spline setup as the VL turbo, V8 commos, XR6 etc.
However the six cylinder rear end would be either 3.7:1 or 3.889:1 ratio, where the 4 cylinder one is 4.1:1.
The gun setup would be an LSD or spool in a skyline housing with a pintara 4.1:1 gearset (or even lower, I believe the same basic BW diff is in a huge range of aussie large cars). That way you'd get a decent gear ration, the discs you want, and the strongest axle setup.
The only bad thing about the R31 rear discs is the calipers have a habit of seizing up (so use reco ones), and the handbrake, at least in the R31, isn't very strong. Though that may be rectified somewhat by only having to pull up an 800kg car, not a 1300kg one...

I just think that althought the BW diff is easy and economical the LSD is pretty crap and clunky compared to say a hilux lsd or even a mazda lsd. Im not the only only who thinks these lsds are a waste of money and time so consider other options if you can you have been warned.
Not all LSD are the same in quality and the BW is on the bottom of the pile.
Although can handle some punishment they arent a performance LSD after all they are a BW.

I have a Skyline LSD in my 1200 and I have found it neither crap nor clunky out at the QR sprint meets and on the street. I also know of a highly modified 13B turbo powered RX7 that has been running the same diff for several years and still pulls impressive 60 foot times.
They are inexpensive to purchase and recondition.
Comments regarding the handbrake are correct. It is far from optimal.
Matty

D, there are a heck of a lot of different BW LSD centres available, and a heck of a lot of different ways to set them up.
I don't really understand what "pretty crap and clunky" means in any case, given that as far as I know all those LSD's you mentioned are pretty similar in basic design.
Certainly all the Silhouette's I've been in haven't been particularly clunky or noisey in their LSD action. They can be prone to "single spinning" when they are up in the high mileages, but a well rebuilt, shimmed, sprung etc centre should be quite good.
Just taking a 15+ year old skyline diff, shortening it and jamming it in the car will produce just as crap a result as any unrebuilt 15+ year old diff will. Bottom line? if you've driven crappy BW skyline diffs, its most likely either age or poor setup causing the problems.


The Skyline diffs can be clunky or whiney (whether open or LSD), but they can be set up properly to eliminate these problems -and the problems seem confined mainly to the original car - most often due to the pinion carrier bearing wearing and allowing the pinion to ride up and down on the crown wheel, and harmonics in the 3.7:1 and 3.889:1 ratio CWP sets. Easily fixed though.

There are also NUMEROUS aftermarket options for the BW centre, from the 4WD systems mechanical locker, Detroit TruTrac, through to KAAZ aftermarket Torsen centres.
In any case, you get the correct stud pattern and a housing thats a heck of a lot lighter than a Mazda commercial or Hilux diff.

Im running a bw vn 4 pinion diff in my ute and i know that il never blow it up there plenty off 10 and 9 second vl turbos down here with the same setup.The diffs in the skylines are 4 pinion but unless you get a silloette or gts diff they only have 25 spline axels

Quote:

mazda LSD = way overpriced and prone to excessive wear on even a std rotary. not very well suited to even a moderately powered vehicle. significant mods are required to make them last even a season in track cars.

i know. i speak from experience here.

hilux LSD = friction plates don't have enough surface area and are prone to slip with shock loading - splines on the 'plates' have been known to bend too.

BW LSD = great compromise between size, weight and tractability. almost a viscious type LSD in the way it feels when driving, except BOTH wheels spin

if you have IRS, the Subaru's are a nice tight LSD inside their R160.

if you want an LSD that "doesn't" slip, then a detroit locker is your only option - and not everyone likes that "locked-now-unlocked-now-locked" nature of them.

Thanks for that added info on th BW's Floody and 240C its good to know.

Another thing the strength of the diff can mean 2 things the strength of the centre or strength of the casing and axels when I talk about strength I mean over all centre, axels and casing. For example 9-inch ford diffs have a rep with the V8 boys for being a strong diff (which it is) but the LSD centre is not so good all (most) of the V8 boys run mini or full spools other wise they would be breaking centres every burnout.