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luke87gt

S30 Rear Diff Details

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Hi guys, 

 

im hoping you may be able to share some details on the stock S30 rear differential? 

 

Is it open or limited slip? And how strong is it? For example, how much power can it support at the drag strip on drag radials for example? 

 

Thanks 

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What year S30?  The early-year cars came with open R180s, and some of the last year cars came with R200s.  I don't believe any of the standard differentials were LSD from the factory.  Most people putting down serious power in straight-line applications use the R200...it's quite a beefy unit.  There are quite a few threads here about the different options available, so search and you should find all the info you could possibly want, and make sure you check out the pinned threads too.  Hope this helps.

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Don't recall exactly, but I think it was around '74/'75 that the cars started receiving the R200 (slightly different for 2+2 vs coupe; automatic vs manual).  It's irrelevant if you're wanting to put one in your '72....just shop for a long-nose R200 in decent condition.  You'll need some other pieces to complete the swap (e.g. mustache bar, driveshaft yoke companion flange, etc).

 

Cheapest "decent" LSD is made by OBX....manf in China.  All over ebay for $400-500. There are some cheap fixes to dramatically improve its baseline performance and reliability.  Search "OBX washer upgrade".   Prices go up dramatically for other R200 LSDs.

 

As mentioned previously, you should be able to find all the info you need by searching....this is a popular topic that has been addressed extensively over the years.  Here are just a few:

 

Edited by jhm

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You can also install short nose R200's using an RT mount.  Techno-toys, among others, Sells these so you can put in LSD's from 350/370Zs.   Just make sure you know what diff you're buying.  I don't remember what z31's had the long nose bolt up LSD's maybe 87/88' turbos?

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No. An RT Mount will not support a shortnose R200. It can only support a longnose R200 and R180.

 

Installing a shortnose R200 is a very custom job that requires new front end and rear mounts.

 

It would then also require custom adapters to use the stock axles, or a very custom knuckle to support a different axle.

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On 9/1/2018 at 5:39 PM, luke87gt said:

Hi guys, 

 

im hoping you may be able to share some details on the stock S30 rear differential? 

 

Is it open or limited slip? And how strong is it? For example, how much power can it support at the drag strip on drag radials for example? 

 

Thanks 

 

Question has been answered many times.  There are whole web pages dedicated to your question.  Google "r200 swaps" etc.

 

Search HybridZ and classiczcars.com

 

 

Start here:

 

http://www.zhome.com/ZCMnL/tech/GearRatios.html

 

http://www.zhome.com/ZCMnL/tech/R200.htm

 

http://www.jasonparuta.com/?page_id=1507

 

 

 

Edited by Miles
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On ‎9‎/‎26‎/‎2018 at 1:08 PM, Neverdone said:

No. An RT Mount will not support a shortnose R200. It can only support a longnose R200 and R180.

 

Installing a shortnose R200 is a very custom job that requires new front end and rear mounts.

 

It would then also require custom adapters to use the stock axles, or a very custom knuckle to support a different axle.

 

Earlier RT mounts were for the short nosed diffs.   I was looking and I can't find the pictures but the Techno Toys Short nosed mount is what I'm talking about.  It moved the nose mount back a ways, yes you have to have your moustache bar modded too. But you CAN put in a short nosed without too much trouble.  In J mortisen's link above, this is the RT mount I had seen before.

 

diff_mount1_Medium_11[1].jpg

Edited by Pharaohabq
clarification

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11 hours ago, Pharaohabq said:

 

Earlier RT mounts were for the short nosed diffs. 

 

 

That's not right.  Somewhere out there is or was the thread where RTz described developing the improved mount for the long nose R200, because he kept breaking his stock mount on a small block chevy transplanted Z.  Can't find that one, all of the old links are broken with the site changes, but here's a similar one.

 

http://forums.hybridz.org/topic/50209-ron-tyler-style-front-diff-mount/

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5 hours ago, NewZed said:

Somewhere out there is or was the thread where RTz described developing the improved mount for the long nose R200, because he kept breaking his stock mount on a small block chevy transplanted Z. 

I think this is it,  page 3 halfway down,

In 1997 I had completed and was campaigning the LT1/T56 powered 240z http://forums.hybridz.org/index.php?/topic/52346-lt1t56-240z/

 

Bob Maggio had completed the same swap in a 280z roughly six months prior but, as far as anyone knows, it had never been done in a 240. There was no documentation and no HBZ.

 

I was having problems tearing the diff mount. I don't recall how many mounts I tore or how many band-aids I applied. What I remember is, Friday afternoon, 'busting another'... with a race scheduled for Saturday. At the time, I was much more fanatical, and this was an EMERGENCY dammit! All I had on hand was some scrap aluminum, a MIG machine, and a local, cheap auto parts house. In desperation I built the ugliest diff mount in history. If you've ever welded aluminum with a MIG machine, you'll likely empathize with that sort of 'fun'. I was gun shy and concerned about tearing the isolators again. The long nose R200 has four holes right? Why not *TWO* turbo 350 mounts? So there it was, in all it's funk... two trans. mounts, on top of the diff, mated to a soda can bridge, a few hours before flag down. It survived the race.

 

At the time, I was also struggling with driveline vibrations. This led to further experimenting. Pinion angles, lower contact areas, shaft material, and so on. In the end, I built a steel 'bridge' with a single, shim-able, GM mount. I was on mount number three or four by this time. It was simple and I was making progress.

 

I don't recall the specifics, but I remember a few of us talking long distance. JohnC, Rags, Ross Corrigan, Pete Paraska, Jim Biondo, BRAAP, etc. This was before HBZ's time. In fact, it was before Internet forums were generally in vogue. Pete and I began discussing this very topic, and I shared my 'experiment'. He asked me to replicate it for him. So, I made ONE more, expressed my desire to avoid production, and asked him to keep the cost to himself ($20.00!).

 

Pete kept his promise, and posted the mount and prints on his website.

 

Regarding the donation, my relationship with Roostmonkey is top secret :mrgreen:

 

The few I built for myself are destroyed. Does this make Pete's a collector item? :P

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Okay, Whatever, my point is that a short nosed Diff can and has been done. Maybe I had the name of the mount incorrect, but I only knew it as an RT mount.  If RTz would comment then we'd know.  Until then I'll stick with my shortnosed plans.

 

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