R31 diff conversion

[RA40-Rossco]

gday guys just wondering who has done an R31 diff under a celica or sprinter, if so did you shorten the diff, one side or both? as i want to use it at full width but am concurned about the offset pinion flange causing driveline issues?

am i worrying about nothing?

[Sam_Q]

I have done 3, two under ae86's and one in a KE70. I didn't shorten any of them and just moved the mounts directly over. I am going to be doing a TA22 conversion soon enough though and I will shorten that one. Whatever you do don't put your short axle into the long side and shorten the housing to suit.

What car do you have in mind?

[3jcelica]

I have one in a ke70, I did not shorten, but have to run FWD offset and flared the guards. The pinon itself is not offset, just the crown wheel which results in one short axel and one long axle.

Fairly easy conversion just move the mounts accross (I cust and shut mine because it was easy and doesn't see the road. good LSD are hard to find, minispools are cheap and easy but I would hate a locked diff on the street. Changing the diff ratio is a bitch and really requires a workshop. To get a reasonable ratio I used a pintara housing, skyline carrier and skyline axles.

Roger

[Sam_Q]

for a ke70 I have a hunch that shorting the short side 68mm will offset the pinion equally to the other side and bring the housing back to a 1410 face to face measurement. The original hand brake cables are not too bad to adapt either.

[hemi twofifteen turbo]

Plenty of decent LSD's available. Cone type are fine as long as they are shimmed correctly. Ratio swap is also fairly easy too, the trick is to match the pinion offset from the donor ratio to your existing and no need to shim the pinion which makes it a HEAP easier.

[RA40-Rossco]

going under my RA40, with Silvia offset wheels, my measurements say it should fill the guards near perfect, its getting a lockrite (detroit style) mechanical LSD installed when i do all the work and 4.1:1 gears, will only ever see the track

[Sam_Q]

well the axles are meant to be 15mm longer in the ra40 so as a rough guess the diff is proportionally wider as well. That means you will only gain an extra 20mm or so either side, which should make it pretty easy to package. Now try and get an R31 housing, it's surpringly hard to source because of one dickhead who owns a shop and takes all the centers out at the wreckers

[NME308]

Done the R31 borgy into the TA23 without shortening. The standard 13inch stockies fit nicely and fill the guards out nearly to the edges.
Lockrite diff locker is great - just takes a little time to get used to on the street with the clunks and bangs and driveline shunt if you mismatch the corner speed and engine revs in 1st or 2nd gear!

I got mine out of Perth WA off the R31Skyline forums with the lockrite for $500 and ego freight deposited it directly across the country for $100! Your options are no longer limited to the city in which you reside.

Cheers,
Jason

[RA40-Rossco]

well the axles are meant to be 15mm longer in the ra40 so as a rough guess the diff is proportionally wider as well. That means you will only gain an extra 20mm or so either side, which should make it pretty easy to package. Now try and get an R31 housing, it's surpringly hard to source because of one dickhead who owns a shop and takes all the centers out at the wreckers

R31 diff housing is sitting under the carport already, yea i measured 20mm a side gain which will have the guards very full

what did you do for a rear flange, just get the rear half of the shaft re-made with a skyline flange on the diff end?

[3jcelica]

I found that the tailshaft needed shortening, so I got a skyline end put on. You could redrill the tail shaft flange if you where keen because it does locate nicely (on the ke70 tailshaft, not sure about the ra40).

Roger

[Sam_Q]

I have just sent people away to get it professionally modded.

[RA40-Rossco]

any tips on removing the diff mounts off the old diff to re-use?

or does anyone have anything drawn up to have plates laser cut with different mounting holes to be able to adjust arm heights and squat angles?

[Sam_Q]

yeah weaken the mounts before you put it into the jig, makes it easier. I have used a grinder every time to take mounts off and I think it's part of the reason I have yet to have a housing warp

[RA40-Rossco]

yeah weaken the mounts before you put it into the jig, makes it easier. I have used a grinder every time to take mounts off and I think it's part of the reason I have yet to have a housing warp

its not a real neat process removing them with the grinder, or do you actualy take a peice from the diff tube and neaten it up once the jig is removed?

[Sam_Q]

no I do the not so neat process, I do it in a few cuts with a slitting disk and take it off like that, I do make deep cuts into the housing though to save as much of the mounts as I can. I find when welded up it looks the part.