Jpn Rear End

Hey guys, so I've been looking for options to replace my tired and shitty open diff in my mk1 hatch. And I haven't found much information. The diff I'd like to toss in there is a Cusco type-RS. In their product sheet, they actually list a part number for the S12 Silvia (BS12 chassis code). Im not sure if this is the RS or not, but the engine listed is a CA18DET.

My question to you is if the rear ends are identical or not. I want to know if this will be a direct bolt in to my current diff housing. I have an 85 mk1 hatch. The years listed on the site are 86-88.5.

Link: http://www.cusco.co.jp/en/pdf/L.S.D._nissan.pdf

Thanks so much,
Dan

If you have a turbo model, and you know for sure it's an R200 long nose(could have been a motor swap or replaced diff or whatever), then you can run S13 LSDs for an OPEN CASE/AXLES. The R200 between the longnose and the short nose CENTER diff is the same. The only difference is the ring gear and the ring gear bolt size(you use your original ring gear and depending on year, you might need a 12mm to 10mm spacer for the ring gear). Just make sure it's NOT FOR S13/S14 OEM LSD casings.

My car is originally a turbo ca18et mk1. I do believe then that it would be an R200 size diff. So my question is, do I need to order the US12 diff, the BS12 diff, or the S13 diff.

If mine is an R200, then why would I need a spacer when using an diff made for an S13. Are the ring gears not the same size? I think I need to see some sort of diagram haha, I'm not even sure what you are describing, but I really appreciate the promp response.

Dan

The bolt size to the ring gear is an m10(10mm), while the holes on the diff that hold the ring gear are 12mm, so there is a 2mm difference. So you'd pretty much need a bolt that is m10x1.25 with a 12mm shank.

If you want to get the S12 one, go for it. I don't know what the B or U s12 trim is for, so you'd have to look into it. It could be for the different sized ring gears or even the R180. I don't know. But I do know the S13 LSDs meant open diff axles will fit and work into the r200 long nose. I'll try to get you more info as I'm busy ATM and will get back to you.

Just checked the product sheet more carefully, and it lists all R200 diffs in, at least the silvia family, as identical part numbers. So I guess that answer my question.

Another question in regards to final drive. So I have in my turbo mk1 a 4.11, what needs to be done to fit a 3.90 or something lower than what i currently have. What cars would I take the gear from? What exactly do I need?

Dan

i believe SE diffs are 3.9, and you wouldnt have to use spacers on them. your drive shaft wouldnt bolt up, though.

why on earth would you want to go from a 411 to a 390 on a 4cyl with little torque?

Are you sure that it's 4.111? Here in France (Europe) we have 3.700