Subaru R160 vs R180, what are the limits of each differential?

[B^2]

Right now I'm running a stock datsun diff in my 1970 510.  It's clunking a bit and I've been thinking about upgrading to either a subaru r160 or R180.  I'm thinking for now that I'd like to run a 4.11 ratio which the r180 never came in but wondering if I'm going to be limited down the road with an R160 diff if I decide to do an engine swap to something with closer to 200hp+  I'm certainly not launching my 510 or drag racing but I also don't want to worry about the rear diff being a time bomb with an engine swap down the road.  At what hp/torque do the r160 diffs start to fail, what numbers can the r180 withstand?  It seems like it would be quite expensive to get gears for an R180 diff to swap it to 4.11 so each diff comes with compromises.  Ultimate goal would be to do a cv conversion too and I'd really like to avoid buying an r160 now, just to upgrade to an R180 in a year or so.

[bertvorgon]

For what it is worth, my R180 has been in service since 1978, factory LSD and 4:62 gears. It has done over 27 years of Solo type starts, on sticky race slicks, hillclimbs and some road race track days. It has never missed a beat and that is with 250 HP to the rear wheels, close to 300 at the crank. I have only ever used the factory half shafts and stay on top of maintenance on those.

I would go with the R180 and be done!

[iceman510]

I think there were 4:11 R180 diffs, I believe the S12 200SX and maybe also the front diff of 720 4wd trucks.

[datzenmike]

Only the non turbo CA20E standard and automatic S12
'83 and up 720 4x4 but check the engine tag on the inner passenger fender under the hood hinge.



Bottom right HF 38
H.... Salisbury style 3rd member
F..... ring gear diameter 190mm
38... 3.889 so 41 would be for the 4.11 ratio. 37 for 3.70 and so on

[icehouse]

Like I said on Ratsun, Just don't get a VLSD.

[B^2]

Any chance this would work: https://www.ebay.com/itm/125444462824?_ ... %3A2047675

[funwithmonkeys]

That would work. You will just need the clip in axle stubs.

[Pjackb]

FWIW
for my 260Z I got an R180 4:11 from a 200SX which was cheap ,
I brought it to my local transmission shop and they swapped the buttons from a Z R180 for 100$
I put 180lb/ft at the wheels

[B^2]

I managed to find a sti 3.9 r180 lsd diff. 4.11 is probably a better gearing for my L20B currently but I'm just going to run the 3.9 and maybe upgrade the engine down the road.

[defdes]

If you find an open diff with the gearing you want, the swap over of the LSD unit is pretty straight forward.

[B^2]

I ended up putting a R180 subaru LSD with 3.9 ratio. 4.11 would probably be better for the engine I have now but didn't want to fuck around with swapping the core.

[iceman510]

What stub shaft/axle option did you choose?

[B^2]

I got the datsun restomods cv axle kit.