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Thread: KGC/Z Diff options?

  1. #1
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    KGC/Z Diff options?

    I've read somewhere that some folks are using LSD's from subie's. the local junk yard has a TON of subies, even some really nice looking STI's so I'm thinking about ripping one apart and checking into this. has anyone else read this too?
    im not sure what years are supposed to be compatible, but we have a ton of GC8's just rotting away over here, so that what i will probably try to swap in.
    I think i read that in a Z forum. i can get a GC8 rear diff for probably under $100 at the junk yard, so i think it would be worth while.

    any thoughts?

  2. #2
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    Re: KGC/Z Diff options?

    Depending on which diff/axle setup you currently have will determine what else you need.

    R180 and R200 have more differences than just overall size.
    1) The moustache bar is different in both shape and mounting hole space.
    2) The stub axles are different as well. Spline counts are larger for the r200s.

    If you still have a wimpy R180 then it should be easier to swap over. What gear ratios are in the Subie diffs? If the gearing is weak then I do not suggest it. Hold out for a good R200 LSD.

  3. #3
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    Re: KGC/Z Diff options?

    i would retain the ring gear, basically only install the differential itself, and use its output shafts. so the housing would still be the Hako case, my mustache bar, would not be affected.

    i may still pick one up to experiment with, maybe not.. who knows LOL i could just wait and look for a Z with LSD in the states.. they are very common in the junk yards. unlike here in Japan. NOTHING is common in the junk yards.

  4. #4
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    Re: KGC/Z Diff options?

    AFAIK the Scooby STI R180 diffs just bolt up with no problems, but you need to swap over the front flange (that bolts to the pinion) from the Nissan diff. Also the STI side axles aren't compatible with the early Nissan driveshafts (with the bolt in the middle), so you need some sort of adapter axle like this one, which clips into the Scooby diff, and the flange is Nissan-friendly: http://www.betamotorsports.com/products ... php?cat=11

    Subaru R180s seem to come in 3.9, 4.1 and 4.4 ratios, and depending on age, will be a TrueTrac, Torsen or 2-way plate centre.

    The other requirement which I think might be required, is that the Beta side axles use the modern-style spline, where they slide into the diff and spring-clip into place (as opposed to the KGC driveshafts which bolt to the diff centre). At full-droop, the KGC driveshafts are at maximum extension, so I think if you wanted to use the clip-in style of side axle, you would need to use a shorter rear shock, or come up with some sort of droop limiter to prevent the driveshafts from pulling out of the STI diff. I'm not sure how much of an issue this would be in practice tho

    I've got a 4.4 STI plate diff and a pair of the Beta Motorsports axles in the garage, but been too lazy to fit them, so I can't vouch for how it all works out

    Alternatively, OS Giken does a Super Lock LSD centre for the old-style R180s, but it's pricey
    Hidden Content Originally Posted by datsunfreak
    No Kev, you are eating a duck fetus.

  5. #5
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    Re: KGC/Z Diff options?

    i know i can get the diff really cheap, but do i really want to lug an 80lb diff around if its not gonna fit anything i own LOL meh.. its worth it in the end..

  6. #6
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    Re: KGC/Z Diff options?

    The R160 guts are not a simple bolt on with the R180 ring and pinion. The sizes are 20mm different. Get a R200 LSD for yahoo auction ($500) modify your moustache bar and be done. LSD diffs stateside are rare in junkyards. I have only found one in the past 5 years. East coast may be different, searching the Z car forums; they come up for sale every so often at $750-$1000 depending on ratio.

    The 510 crowd uses the entire R160 unit and axles complete in their cars. Not swapping the guts out.

  7. #7
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    Re: KGC/Z Diff options?

    Actually Tim, since you're in Japan, you might have a chance of finding a factory R180 Nissan LSD. You would be looking for an early one, where the driveshaft has a central bolt (in the middle of the spline) that goes into the diff.

    They used to be quite easy to find say 15yrs ago, but nowadays are extremely rare over here in Australia. If you could find one, it would bolt up no probs, and you could get it rebuild/shimmed when you get back to the States (they'll all be quite worn out by now, unless they were replated at some point).
    Hidden Content Originally Posted by datsunfreak
    No Kev, you are eating a duck fetus.

  8. #8
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    Re: KGC/Z Diff options?

    nice, i will keep an eye out, im sure the rare factor will add to the price lol

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