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jeffball610

R200 LSD options/setup

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So I've come to the conclusion that I will never find a stock longnose R200 LSD for a reasonable price, and I'm shopping for aftermarket solutions for my 4G63 powered Datsun 510. I've basically landed on the Tomei 2 way clutch unit, but I'd like to get others opinions on the topic. I mostly street drive my car, but I do autocross events and I'm hoping to make my first road course event in January. Is a 2 way the right choice, or should I look at 1.5 or even 1 way LSD options? This is going in a light weight chassis (lighter than any vehicle that came stock with an R200), so should I be concerned with the engagement setup? With a clutch type, you can swap out the stacks to get a particular engagement and slip. Would anyone recommend doing this over the "stock" setup? I have a feeling that the standard "out of the box" setup might be too harsh. I plan to do the install myself, so I'd like to have as much info as I can before proceeding. Also, since this is a longnose unit and the aftermarket options are for the shortnose units, who still makes the bolt sleeves to make this work? I think Z1 used to sell them, but I haven't seen anything lately.

 

I'm open to advice and options. I'd rather not get an OBX unit, but if a mechanical LSD is the best choice, I might take a chance. Are there any other concerns I should be aware of before taking the plunge?

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I believe you can buy an aftermarket LSD kit meant for the short nose R200 and use it in the long nose R200 as long as the long nose you have is from the last of the Z31. (1987-89) Those will have the 12mm bolts inside and match up with what also came in the S13. I tried to find an article or video to confirm this for you but I came up short.

 

Beyond that I don't have any good suggestions on 1.5 or 2 way. I don't have any experience with LSD. I just bought a factory Nissan one recently but haven't even gone through it yet.

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I've driven on a few Tomei R200's (for the late model cars, not the early diffs) and loved them right out of the box. They're pretty tame for a clutch type, especially when compared to a more aggressive NISMO GT PRO that make the car sound seriously broken when making low speed tight turns from axle binding. One of our guys here at Z1 has one in his 580whp 350Z, which is an absolute machine. Amazing how easy the car is to control on power when compared to the stock worn out VLSD, which is scary inconsistent. We use Red Line Slip Friction Additive which helps smooth it out at low speed and eliminate all of the annoying chatter. 

If you want the more streetable option, the 1.5 way is the way to go, since it is has less aggressive lock-up characteristics on decel/braking which gives it a bit more neutral feel and better control.

Clutch Type Diffs:

 

1-Way: Weird setup, from what I understand they behave somewhat like an open differential. Supposed to be nice in FWD applications, doesn't seem like there would be a benefit in our applications.

1.5-Way: Less Aggressive Decel, Best for tight courses where you make quick left to right transitions, like autocross for example. Much more forgiving than a 2-way differential, usually my go-to choice.

2-Way: Full lock-up during decel and acceleration, good for road racing at high speed, not as good for technical courses with tight corners. Great for producing oversteer because of its lock-up characteristics so drifters love them.

(Spoiler alert, I work for Z1 so feel free to PM me with any questions.)

Edited by metalmonkey47

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So I broke down and bought a Tomei 1.5 way. However, their doesn't seem to be any good info on setting up an LSD. I have the specs for the Tomei's initial toque and there's even a drawing of the clutch plate set up, but they only have directions on how to increase initial torque, not reduce it. That being said, I'm not sure what torque figure I should be going for. The 510 is a pretty light chassis, and it's not like I'll be making 1000hp on big sticky tires, so I'm assuming a lower initial torque set up than "stock" is what I should be going for.

 

I'm trying to compare numbers between the R200 and smaller cars like the Miata to see if it makes sense. However, I don't know if the Miata numbers are for stock N/A setups, or something more. Does engine power mean anything in an LSD? Is it all friction from tires and rolling mass? Does anyone have a solid number to build from? How do I measure initial torque on a bench?

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My rudimentary understanding of LSD's and differentials in general is that a clutch pack LSD is affected by the breakaway weight or breakaway torque from the friction on your wheel. Ex, if the breakaway "weight" is 35 lbs, then there will need to be at least 35 lbs of friction on the inside wheel to make the LSD engage and do its job. A street car and autocross car should probably have a lower breakaway so you can still actuate the LSD on slow turns. 

 

I don't think that you'll need to worry about the power you're pulling from your motor with that R200. 

 

I am right now rebuilding a r160 LSD. It's a clutch pack LSD and has a 45-lbs breakaway. Is the Tomei a clutch pack or Quaife/Gleason-Torsen or what? If it's a clutch pack, the breakaway is adjusted by shims inside the spool (i would imagine they tell you somewhere what the setting is).

 

I have heard people measure their breakaways by putting a torque wrench on one half shaft and a prybar on the other and seeing at what weight it, well, breaks loose. 

 

Somebody should check everything I just said.  ^^^  I am currently going through the same kind of rebuild, and with a r160, not a r200. 

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Not a bench test but you get the idea. Lock one side and add lbs of torque to the other until it slips.

 

 

 

 

 

 

The diff needs to be big enough to handle high power/torque, but on a light 510 that's less of an issue. The proper amount of  breakaway torque on the clutch plates is all about the moving mass and tire grip. BTW, what stub axles do you have?

 

 Have you considered the 2005 + Subaru WRX sti R180 CLSD? 2009 and older have Helix/Torsen LSD with 3.90 ratio. I have that in my 350 hp SR swapper 510 and it's performed flawlessly. Super light and nimble, but always delivers tons of corner exit and acceleration grip. 

 

I know you've already invested in the R200, but I felt compelled to say something. 

 

 

Edited by paradime
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21 hours ago, paradime said:

The diff needs to be big enough to handle high power/torque, but on a light 510 that's less of an issue. The proper amount of  breakaway torque on the clutch plates is all about the moving mass and tire grip. BTW, what stub axles do you have?

 

 Have you considered the 2005 + Subaru WRX sti R180 CLSD? 2009 and older have Helix/Torsen LSD with 3.90 ratio. I have that in my 350 hp SR swapper 510 and it's performed flawlessly. Super light and nimble, but always delivers tons of corner exit and acceleration grip. 

 

I know you've already invested in the R200, but I felt compelled to say something. 

 

 

My swap consists of using Z31 5-lug hubs and bearing housings that are welded in the stock 510 location. This allows me to swap in Z31 CV joints and use a Pathfinder axle shaft with no other modifications other than the mustache bar. Looking at what Tomei lists, I'm thinking the breakaway torque is about double what others say I should have. They list 16.5-18.5 kg/m for the R200 while smaller and lighter cars like the Miata are around 6-8 kg/m.

 

The test shown cannot be performed like that on my car since there is no center nut to torque on. I'll see what I can do to test it, but I think I need to talk to Tomei or a shop first to see if I can lower the breakaway torque significantly. They do have a procedure for increasing torque by about 10% by using two 0.1mm thicker clutches. I might be able to simply remove a clutch or two and still have something that works properly.

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Holy crap, the 510 is 150 lbs. lighter than the Miata... LOL You're going to have those guys at Tomei scratching their heads when you ask them how to reduced breakaway by half. 😆 

 

I didn't know R200s were a thing with the Miata guys but you might want to poke your nose into a few Miata forums to see what they're doing. Best of luck man, that 510 of yours sounds like a work of modding art. I've never heard of anyone cutting out and welding in the entire Z31 hub and bearing housings on a 510 trailing arm. Dude that some seriously crazy stuff.  

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On 1/3/2019 at 2:07 AM, paradime said:

Holy crap, the 510 is 150 lbs. lighter than the Miata... LOL You're going to have those guys at Tomei scratching their heads when you ask them how to reduced breakaway by half. 😆 

 

I didn't know R200s were a thing with the Miata guys but you might want to poke your nose into a few Miata forums to see what they're doing. Best of luck man, that 510 of yours sounds like a work of modding art. I've never heard of anyone cutting out and welding in the entire Z31 hub and bearing housings on a 510 trailing arm. Dude that some seriously crazy stuff.  

The R200 is not a thing with Miata guys as far as I understand. This is just a comparison between LSD options that Tomei has.

 

The hub welding idea is not mine. There were a few guys that did it a number of years ago. I just followed them as best I could. This just seemed like an easier and cheaper option than custom CV axles and sourcing R180 LSDs (or so I thought).

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I would have thought sourcing a r200 would be more difficult than a r180. Maybe not new or rebuilt, but junkyard fun times! r180 came in maximas and 810s and things (not that you can find 810s in junkyards anymore 😣).

Either way, you're working with a R200. I know that you have a bunch of things already converted for the 5-lugs and such, but I'm wondering if, like the sedan, there is a clearance issue for the larger diff casings. People have needed to chop or modify the spare tire well in the sedans to get the r200s into the stock crossmember, or pull out or modify the rear crossmember entirely. Do you have the same problem with the wagon, or is there more room for the swap?

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The wagon has a straight axle with leaf springs. not the same diff suspension at all.

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5 hours ago, BambooU said:

Either way, you're working with a R200. I know that you have a bunch of things already converted for the 5-lugs and such, but I'm wondering if, like the sedan, there is a clearance issue for the larger diff casings. People have needed to chop or modify the spare tire well in the sedans to get the r200s into the stock crossmember, or pull out or modify the rear crossmember entirely. Do you have the same problem with the wagon, or is there more room for the swap?

I did have to cut an area out for the mounting studs. There is a "support" that runs in that area. I only cut what was necessary, and it doesn't seem to affect anything. The biggest issue is that you can't just drop the diff out. You have to either let the crossmember sag, or remove the whole rear suspension. I'm thinking I might make a mustache bar that un-bolts from the mounts to make it a drop out unit eventually.

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I got my Tomei unit today. Seems like a solid unit. The direction booklet that comes with it doesn't have any info that I don't already have. I'm still unsure of how to reduce the initial torque, because no one likes to answer phones or return calls. I don't see any info on the internet either and I've yet to see anyone install a Tomei LSD that does more than drop it in. I hate being the one to break new ground, but a man has to do what he's got to do.

Edited by jeffball610

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Just drive that thing dirty, it'll loosen up 

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The breakaway is just a number. Handy to know which way to go if increasing or decreasing. Too many variables to really draw any conclusion about what will work for you. Springs, tire type and traction, shocks, car weight, gearing, sway bar... Make a guess and try it, then adjust up or down.

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Small update. I spoke with Tomei USA and they said there might be a way. They are contacting Tomei Japan to confirm.

My thought was to reduce the contact between inner and out clutches. Currently there are 4 inner and 4 outer clutches on each side. That gives me 7 points of contact on each side. If I swap around the clutches to have 2 of each touching (2 inner and then 2 outer etc) I can reduce the contact down to 3 points.
r200-specs.png
If my math is right, that should be a 62% reduction in surface area and effectively giving me 9.57kg/m or about 69ft/lbs which is what everyone seems to be telling me to shoot for.

I seriously have no idea if this will work, as I have zero experience with diffs or anything of this nature. If anyone has any good ideas, let me know.

Edited by jeffball610

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21 hours ago, datzenmike said:

The breakaway is just a number. Handy to know which way to go if increasing or decreasing. Too many variables to really draw any conclusion about what will work for you. Springs, tire type and traction, shocks, car weight, gearing, sway bar... Make a guess and try it, then adjust up or down.

I'm basing my data off of other 510s and their similarity in weight, size, and wheelbase to a Miata. I'm then comparing it to what Tomei offers and guessing as to what I should be going for. I have zero experience with this, so it's all guesswork on my end.

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That's all you can do realluy, get what works on a similar car and try it.

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It's installed and broken in. I haven't taken it out yet since I changed the fluid, but my initial impressions are it's noisy and clunky. I assume it just needs to break in more, but I'm sure I have some bushings that need some refreshing.
IMG-4556.jpg
IMG-4557.jpg

I still don't have a proper torque reading. I followed the Factory Nissan manual for checking the torque at the wheel, but it just says if it's within spec or not. I got a reading of about 60ft/lbs before break in, and about 50ft/lbs after using a torque wrench with about a 16" handle.. According to the manual, that's within spec, but I have no idea what the actual reading is. I'm sure there is a math equation that I can calculate it, but I don't know it off hand. Anyone have input?
Screen-Shot-2019-01-19-at-3-11-01-PM.png

 

Small update: I took it out for spin. The clunking only seems to be at low speeds. I guess I just need to drive more aggressively 🙂

Edited by jeffball610

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