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GenSport Carolinas
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Discussion Starter · #1 ·
A local contact has listed a Kaaz 1.5 LSD that has less than 2k miles on it.
Kaaz 1.5 Way LSD - Hyundai Genesis Coupe 2010+ - Enjuku Racing Parts, LLC

It's in his 2013 2.0 and I've got a 2010 3.8. I DD the car with occassional weekend trips for aggressive drives for 30+ minutes per stint, tight roads and track.

Questions:
- I understand that it will fit directly in my housing/pumpkin. Is this correct?
- What are the benefits compared to my base diff (non track)?
- What's the downside?
- Is this a good choice, with the understanding that I'm getting a pretty good deal as well?

Thanks
 

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Subd. I want to know answer to these as well...
 

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GCMafia
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It is a direct swap.
You get way more traction than an open diff for obvious reasons...I went from a open diff like ur self to a quiafe LSD, it was a night and day difference not only on a drag strip but like u, spirited runs up canyons and such
If u get for less than 1k jump on it


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Jedi Master
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It is a direct swap.
You get way more traction than an open diff for obvious reasons...I went from a open diff like ur self to a quiafe LSD, it was a night and day difference not only on a drag strip but like u, spirited runs up canyons and such
If u get for less than 1k jump on it


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what i'd like to know, and not able to find, how long does a kaaz clutch last, i've tryed other platforms and some say 3000miles others say 10k depending on use,
 

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GCMafia
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From what I've heard it's every 10k
George or one of the "el_stig" on here is an occasional drifter and he does his around 10k I believe


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Jedi Master
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GCMafia
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Work in Progress
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I'm starting to think the Kaaz or Quaife is the best option. I'm sick and tired of dealing with these salavge yards looking for a diff off a wrecked track and they all claim their diff has the LSD but when I force them to send me a pic, everytime its open and they swear it has the LSD. Nope.
 

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GCMafia
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GenSport Carolinas
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Discussion Starter · #10 ·
Is an aftermarket LSD superior to the track LSD? If so, why?

Thanks again for your help.
 

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The OE diff is a Torsen, or torque sensing. It transfers and multiples output to the non-spinning wheel, they usually have a multiplication factor of 6 or so. However, if you have nothing to multiply (anything times 0 is 0) then the free wheel will just spin and you won't go anywhere, example, one wheel is off the ground or in soft sand and the other is on pavement.

Helical LSD's bias the load and never truely lock either however if one wheel is off the ground the other still has motive power and will move you but the wheel off the ground will spin faster than the contact wheel until the load can be properly distributed again.

Clutch or locking LSD's actually lock and basically turn the rear end into a single piece under load, this can cause some "chittering" when going around corners as both wheels try to spin at the exact same speed. The clutch discs are what offer the slip to minimise the effect and are a wear item, requiring often times frequent servicing.

Best for DD, Torsen
Best for all round, Helical
Best for drift, Clutch/Locker

least amount of service, Torsen (only need to change the fluid if the diff gets submerged)
average service, Helical (every 100k or if the diff gets submerged)
most amount of service, Clutch (fluid changed regularily, clutches replaced as required or if submerged)
 

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GenSport Carolinas
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Discussion Starter · #12 ·
Good stuff.

Kaaz is Torsen. Better than track version? Difference between 1.5 way and 2.0 way? Any downsides? Noise?

Sorry for the shotgun blast of questions. Hope this is helpful for others as well.
 

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I drive a V6
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A helical and torsen are essentially the same thing...they use gears instead of clutches.

Torsen is a brand name...some use helical gears, some use other configurations, all use gears.
 

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The Lonely Driver
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335 Posts
The OE diff is a Torsen, or torque sensing. It transfers and multiples output to the non-spinning wheel, they usually have a multiplication factor of 6 or so. However, if you have nothing to multiply (anything times 0 is 0) then the free wheel will just spin and you won't go anywhere, example, one wheel is off the ground or in soft sand and the other is on pavement.

Helical LSD's bias the load and never truely lock either however if one wheel is off the ground the other still has motive power and will move you but the wheel off the ground will spin faster than the contact wheel until the load can be properly distributed again.

Clutch or locking LSD's actually lock and basically turn the rear end into a single piece under load, this can cause some "chittering" when going around corners as both wheels try to spin at the exact same speed. The clutch discs are what offer the slip to minimise the effect and are a wear item, requiring often times frequent servicing.

Best for DD, Torsen
Best for all round, Helical
Best for drift, Clutch/Locker

least amount of service, Torsen (only need to change the fluid if the diff gets submerged)
average service, Helical (every 100k or if the diff gets submerged)
most amount of service, Clutch (fluid changed regularily, clutches replaced as required or if submerged)
Thanks Snoopy!!

TIL about diffs :)
 

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Work in Progress
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6,496 Posts
It is a direct swap.
You get way more traction than an open diff for obvious reasons...I went from a open diff like ur self to a quiafe LSD, it was a night and day difference not only on a drag strip but like u, spirited runs up canyons and such
If u get for less than 1k jump on it


Sent from AutoGuide.com App
PM me where you got yours if you got it for less than 1K
 

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never use only drop once!
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Okay. There seems to be some confusion here:

1. CoupeDeVille. You can find an OEM LSD on ebay...there's some national wreckers that usually have some but you'll have to keep looking. They post pictures. All LSDs will have a sticker that says "LSD" on the differential. They call them "rear carrier assemblies" not "rear differentials". Might turn up some more hits.


2.

Open (standard) versus limited slip (LSD) rear differentials:

Open Diff:

Trq out_1 = Trq out_2 , where 1 and 2 are typically the left and right drive wheels.
Trq in = Trq out_1 + Trq out_2 .

an open differential has a STATIC torque split. usually 50/50. This means that both wheels get equal torque ALL THE TIME. If you have one wheel in the air (no grip, or "100% slip") it will receive a minimal amount of torque since there's no load on that wheel.

(no load means very low demand for power since there's next to no resistance to spin that wheel. Torque is an expression of "work". you don't need to "work" very hard to spin a wheel on a bearing that's got nothing but some air to provide friction) <-----disclaimer...I'm not an engineer. But this is how I understand it as a layman...

Since it's getting very little torque...the stationary (gripping) wheel gets very little torque...not enough to make it spin...which is why only the wheel with no contact is spinning. It has less load, so it will spin before the wheel with contact...and limits the torque to just enough to make it spin at that speed...thus you'll never get un-stuck

A limited slip differential can change that torque split to get that wheel on the ground spinning, even though theres no load on the airborne wheel (most of the time)

An LSD is hyperstatic...in other words...the physical expression is always changing...(torque moves around...you cant just say...well...it's 50/50 split) This is what allows it to actually get torque to the proper wheel.

½ Trq in ±( ½ Trq d ) .... all that means really is that the fast spinning wheel gets half of input (driveshaft torque) MINUS half of the difference in torque between wheels (this is the "slipping" wheel) while the slow spinning wheel gets half of input PLUS half of the difference in torque between wheels (this is the "gripping" wheel). If you think about that for a minute it should become apparent why an LSD gives you so much more grip than an open differential.


The difference between the OEM TorSen and the Quaife is this:

The Quaife always biases torque. So like snoopy said. There is motive force...it will spin both wheels...although the "slip" wheel (off the ground) will spin faster than the "grip" wheel (on the ground)

The TorSen MUST PASS A THRESHOLD torque bias ratio...until then, it acts like an open differential...so if you have an off the ground wheel (or on ice...or sand, or gravel with very very minimal grip) your TorSen is useless, because both wheels are getting near equal torque. It is only when you have both tires in contact (straight line wheel slip from acceleration, or in turning) that the TorSen starts to bias torque....that's the "torque multiplication" that Snoopy was talking about.

In contrast, a clutch type LSD uses clutch packs that stack together and gradually increase pressure on the spider gears as torque increases. That pressure couples the axles together more firmly as the clutches gets compressed.

The only time you say 1 way, 1.5 way, or 2 way is on clutch type LSDs.

The "way" refers to direction. There are three types of torque situations: unloaded, loaded, and overrun.

A 1 way LSD will only apply limiting torque on forward acceleration. Think of a FWD car. If you had an LSD that provided trq_d (limiting torque...or limiting slip...making the wheels spin the same speed...however you want to think about it) with no throttle input...what happens when you try to turn into a corner? Your steering wheels are your drive wheels. If they're locked together and you turn, your inside wheel spins as fast as the outside wheel, you lose grip, the car tries to keep going straight and you get massive understeer...right into a wall...FWD cars use a 1 way LSD for this reason. It's only under acceleration that they try to couple the axles...so when you lift the throttle and/or brake to turn in, your differential relaxes, decouples, and you can safely turn in.

A 2 way means that it will apply limiting torque in forward and reverse so there is limiting torque on engine braking and on engine throttle. This can be as bad as a 1 way for a rear wheel drive car as braking and and acceleration will cause the back axles to lock and cause massive oversteer on turn in....best diff for drifting for the same reason....clutch kick with a 2 way...and you have instant oversteer regardless of throttle input

A 1.5 way means that there is forward and reverse trq_d but the reverse is not as strong as the forward. You still get some limiting torque on engine braking which is good for braking stability (think about it....if one wheel is getting all the power and your brakes apply equal pressure to both wheels, one side of your car is going to try to travel faster than the other side of the car...in other words, you slide out the rear) but not so high that you have to worry about so much oversteer.


There is also a "locking" differential. That is a differential that acts like an open differential, and will "lock" the axles together after a certain torque threshold...or it can be mechanically locked (manually or electronically) like in a 4x4 truck. That forces both wheels to spin at the same speed regardless of conditions. Great for soft offroad conditions...easy way to chunk your differential on pavement...

You could also weld your differential closed...which would make it locked all the time...but this really stresses out your driveshaft where it meshes with your differential.

And there's also brake activated LSDs (if you use 1 brake caliper to slow a spinning wheel, your open differential becomes a limited slip...think about it)

and of course...viscous. Nissan loves these....used on the 240 sx, 300 zx, silvia, r32/33 skyline, 350z, g35....essentially the same thing as an automatic transmission torque converter....uses high viscosity fluid to allow the axles to always be "open" but to limit the difference in speed....they suck

so essentially...if you want to do any competitive events:

Open - Total piece of ****
Viscous - Piece of **** but better than open
TorSen - Piece of **** but better than open or viscous
Quaife - Not as good as a clutch type, but less maintenance, quieter and smoother operation, and actually always acts like an LSD, even under low torque
1 way clutch type - good for FWD
1.5 way clutch type - great for RWD drag or circuit, good for drift.
2 way clutch type - Great for Drift
Locker - Great for Drift, great for drag, **** for circuit...unpredictable...hard on car
Welded - Great for drift...hope its a beater track car.


Electronic/Brake activated - Piece of ****...you're slowing down your car

I think that should clear things up...
 

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never use only drop once!
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and just as a follow up because i typed that up at work and wanted to gtfo.....clutch type diffs are rebuildable...versus a helical where how it actually works is it presses the gears into the differential housing to create the limiting torque. What this means basically, is that you're wearing the gears instead of wearing clutches. Ultimately they become wear items as well. if they're well built, they'll outlive the car...as in the quaife...but if theyre shitty china parts like the OBXs I've read about...they get mangled and eventually are just open differentials.

On top of that. A clutch type does not necessarily lock. A locker will lock...but you can reach a maximum torque differential on a clutch type LIMITED slip theoretically so far as I know. In other words, there's always a difference, but depending on how hard the clutches are sprung...it might as well be a locker. The point is....it's a smooth transition that gets ramped up. What a lot of them do, is the pinion gear essentially climbs up a ramp which increases pressure on a set of rings to compress the clutches. The more the clutches are compressed, the more resistant the axles are to moving at different speeds. So more torque = more compression = more biasing to keep everything even stevens.

Typically a non-modified aftermarket clutch is only going to chatter during low speed turns like when driving around a parking lot. It's not going to be an issue during competition. Also, the clutch type has an advantage over at least a TorSen LSD in that it doesn't require slippage to lock up. If you go WOT off the line it's gonna be pretty much instantaneous lock up to drive both wheels which is going to get you much better 60' and quarter mile times. I really think that's a big factor in the gen's slow quarter times considering the power output.

A lot of people attribute the squirelliness of the stock supra to boost, rwd, and a torsen diff. What I find interesting is that a lot of people had the same issue with this car when it came out. People accidentally drifting around turns and ending up in ditches. Same set up.
 
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