Jump to content

LSD


Guest Random
 Share

Recommended Posts

Guest Random

I had a thought as I was looking under my truck this morning and thought that perhaps I should run this by some of the more experianced four wheelers here as I tend to be a tarmac kind of guy but enjoy automotive performance of any type.

So here goes: I remember reading a long time ago that the Nissan 4X4s with IFS used the R200 gear carrier, this is the same basic carrier that Datsun/Nissan has used for about 30 or so years and I belive that it's actualy manufatured by Hitachi corp. Subies use the R180 in the back end, a smaller version of the same thing.

So if the Carrier on the truck/ P.F. is the same one (R200) this is the same carrier thats used in the Nissan 240SX. In Canada all of these "rear ends" (240SX) all came with Limited Slip as a nod to our northern climate although they diddn't in the United States, why I don't know you guys have plenty of crappy weather. So now that I've covered that I guess I should get to the question part of all of this right?

Discounting the more than likely need to change gear ratios in the carrier itself, how would having an LSD in the front of the truck affect drivability during 2 and 4wd? I have a feeling that you're all going to tell me that it will become an understeering tank but none the less it could be a workable idea.

I look forward to your thoughts,

Ted.

Edited by Random
Link to comment
Share on other sites

Guest Random

Yes I realize that bolting the parts in is not really a problem, what I'm wondering is how will the steering be effected, if it acts like it has lockers in during regular driving than it will want to go straight lots.

Link to comment
Share on other sites

Hmm, I don't know the other vehicles well enough to know why it wouldn't work, other than gearing as you mentioned. Interesting concept... Only issues I can think of off hand is the work and $ for the gears. But why not just install a front locker for the same effect, but better ?

 

B

Link to comment
Share on other sites

Unless you drive around floored all the time, no, it shouldn't be that big of a deal, but I could see really losing it in the snow at 30mph in 4hi if you give it a lot of gas in a corner... :o

 

B

Link to comment
Share on other sites

Hmm, I don't know the other vehicles well enough to know why it wouldn't work, other than gearing as you mentioned. Interesting concept... Only issues I can think of off hand is the work and $ for the gears. But why not just install a front locker for the same effect, but better ?

 

B

front locker for the pathy????

do tell!!!

Link to comment
Share on other sites

Yes I realize that bolting the parts in is not really a problem, what I'm wondering is how will the steering be effected, if it acts like it has lockers in during regular driving than it will want to go straight lots.

steering wont be nearly as bad as having a locked front end, but like was said I think the only time youd really notice a tendency to go straight is if you were powering through a fast turn :oops:

Link to comment
Share on other sites

Great question from a "tarmac kind of guy" :D .......my brother and I both read this post and looked at each other and said "HEYYYYYY!" and nodded, we figure "Why not??". The way I see it, it could actually help cornering because of the limited slip not kicking in until one tire loses traction. Straight forward, no problem....in a turn, both tires will be facing the same direction and pulling you where you are turning, right? I would love to see how something like this would work out, it could be the "best mod for a Pathy beside SAS" :aok:

Link to comment
Share on other sites

This sounds like an awesome idea! And I'm sure you could do the LSD repack that has been described for the rear. And when you're in 2wd nothing should be affected since there's no power going in. I'm in! (Don't know when I'll be able to do it though, I mean I haven't made my gap gaurds that I was supposed to make in mid december).

Finally a solution for the crappy nissan IFS?

The locker they were refering to is the ARB air locker I think, or just a lincoln lock.

Link to comment
Share on other sites

Z swaps have been done, but I think there's a difference with a gear insert or something that makes the 200SX diff unable to be a donor. Probably the same reason those Phanton Grip deals won't work in our front difs.

Good luck finding a clutch-type LSD from a Z car, too. The tuner guys are snatching them all up and they have some deeeep pockets. By the time you win a bid for one on ebay or happen to get one that someone missed at the junkyard you could've bought a new LSD from Calmini or installed an ARB for a little more. I poke around every once in a while for a cheap one, but none have surfaced for under $400 or so that I've seen.

Link to comment
Share on other sites

Guest Random

Yeah I don't know about the 300z or the 200sx either this just seemed like it could be a workable idea and thought that I would present it to the masses for conversation. I can't see why there would be a problem with the gear swap as both units are the R200 carrier. Part of my less than an engineer mind tells me that there shouldn't be a problem in 2wd as there isn't any power applied to the unit from the transfercase, but the other part tells me of scary sheer forces as the front CV shafts try to turn at different speeds during normal cornering, or is this only a problem under engine load? I can see the possible problem with understeer in snow as stated.

It's just an idea, and if it can be made to work I'd be more than happy for anyone who can make use of it. As for e-bay I don't think Canada is out of rearends for 240's yet, get your bid in now lol.

Link to comment
Share on other sites

The 200SX LSD doesn't fit, the output shaft collars or something else are completely different. Won't work AFAIK. The 300ZX LSD does, but you DO NOT want the VLSD (viscous limited slip diff, came in the pearl white SS edition models), because it doesn't work under load the same way as a clutch-and-plate type LSD. The quoted years for 300ZX diffs is right, from 4/87-89.

Link to comment
Share on other sites

Guest Random

I'm not sure what type of LSD the 240sx/ S13 Silvia uses, I suppose I could find out. What is it about the viscous coupling type that's a problem?

So I just got off the phone with a local race shop and the diff is a viscous unit and has about 60lbs of break away factory. I couldn't see this as being a problem in the corners on a heavy vehicle. School me, lol. He did mention a clutch type LSD drop in but that was about a grand CDN and then a Quaife and I just laughted and told him I didn't even want to know the price on that!

 

All the best,

Ted.

Link to comment
Share on other sites

So I just got off the phone with a local race shop and the diff is a viscous unit and has about 60lbs of break away factory. I couldn't see this as being a problem in the corners on a heavy vehicle. School me, lol.

The stock WD21 rear LSD has about 260+ft/lbs of breakaway force. As soon as you lift one of the tires it breaks away, so you can see that 60 ft/lbs is well.. a joke. As for normal driving, it wouldn't have any effect even if it was welded shut. With the vehicle in 2WD the diff won't even spin.

Edited by Filthy Luker
Link to comment
Share on other sites

Guest Random

Has anyone tried to use a more viscous fluid of some type in the LSD to improve the break away?

I don't agree with the idea of wielding the spider gears in the front diff not having an effect on driving in 2wd, even if the carrier isn't reciving power it still spins, it has to because it's directly attached to the cv joints. Have you ever seen a pro street car driving around town with a wielded diff? The back end chirps and "hops" as both the tires try to go the same speed as the car turns, this is because the inside wheel is travelling at a slower rate than outside wheel would like to be going because it has farther to go around the corner. This is bad enough when it happens in the rear, imagine this happening to the steering axle!!! I've driven and continue to drive three axle trucks (big rigs) with trailer(s) and I have in the past locked in the rear axles (4WD true posi) in either bad weather or more commonly now to circumnavigate questionable terrain (dairy farm driveways). This is great if you want to go straight, the bitch with this set up is if you forget that it's locked in and you try to make a 90deg turn onto a street and even fully loaded with 12 or 13,000 lbs on the steering tires you go straight. Wanna talk about pucker factor! lol.

Link to comment
Share on other sites

I don't agree with the idea of wielding the spider gears in the front diff not having an effect on driving in 2wd, even if the carrier isn't reciving power it still spins, it has to because it's directly attached to the cv joints.

if you are considering LSD or a locker up front to increase traction, then I assume you have or will upgrade your auto locking hubs to manuals, because if you didn;t the extra force applied by locking the front end will destroy the autos.

With the manual hub setup you can completely seperate the wheel from the diff.

so your comment is wrong you can weld the front spiders and the only time you will notcie the effect is when the hubs are locked. agreed steering will be difficult on any kind of hard terraign.

Link to comment
Share on other sites

Guest Random

Good point I stand corrected. Most of anything that I work on that has front driven wheels is either front wheel drive or fulltime all wheel drive, I forgot about the hubs.

Edited by Random
Link to comment
Share on other sites

  • 4 months later...

Sorry to bring this back from the dead, but I'm curious about the differences in breakaway forces between the stock pathy wd21 lsd, and the 200 carrier in the 240sx break away (ie 260 lbs vs 60 lbs).

 

Does this mean that the lsd won't do anything effective, as it would break away as soon as any pressure is put on it?

 

 

Or does it mean that the breakaway force is so high that it would make driving a nightmare. I suspect that breakaway would be so low that it wouldn't be effective.

 

If this is the case, could you not rebuild the LSD with clutches from a rear lsd, to make the breakaway forces stronger? Or are the parts incompatible?

Link to comment
Share on other sites

you can put more disks in the rear LSD to make it tighter. you COULD weld all the clutches together and then it would be locked. and IIRC there was a guy on NOR that was trying to machine a hunk of steel to take place of all the clutches, to lock it.

Link to comment
Share on other sites

The stock WD21 rear LSD has about 260+ft/lbs of breakaway force.  As soon as you lift one of the tires it breaks away, so you can see that 60 ft/lbs is well.. a joke.  As for normal driving, it wouldn't have any effect even if it was welded shut.  With the vehicle in 2WD the diff won't even spin.

a little finesse with the brake pedal goes a long way my friend. B)

 

the only locker widely available is ARB, with the onboard air and such you're really looking at $2k. might as well SAS it. LSD up front is a great idea though. it surely would help. they are somewhat hard to come by and rather on the excesive side of things. there are others that wanna use that puppy in their vehicles.

Link to comment
Share on other sites

Not really MZ.

 

ARB Locker - ~$700US (in the contigious 48)

ARB Compact Compressor (all you really need to run the locker) - $140

Shipping - $60

 

Now....installation is where they get you, however, if you pull your 3rd and bring them the 3rd and the ARB and say, hey, put this in here, you can walk out with it for about $2-300 or so.

 

Then install the compressor and air lines yourself (figure on about 5-6 hours for running the wires and switches and what not), put the 3rd back in the truck, hook up the locker, fill the diff with oil and badabing badaboom.

 

Hell, you could even pick up an extra 3rd from a junkyard for about $2-300 and have the shop install the locker in that, and then just swap 3rds and sell off the other one. Any 3rd with the same spline count will work.

 

Now, if you have the shop pull the 3rd and put it back in your truck, you're looking at about $550-600 for that job.

 

It can be done for a LOT less than $2,000 but you have to want it to be done for less than 2k. Having a shop install everything will probably run you about $2k for a rear locker and $3500 for Front and Rear.

 

Or....instead of using the ARB compressor, you only need a compressor that is capable of spitting out bursts of 90 psi ever several minutes....so the Viair 100C or 100H would work, as long as you don't plan on using that compressor to fill tires.

 

http://cgi.ebay.com/ebaymotors/Viair-100C-...067273725QQrdZ1

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share

×
×
  • Create New...