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In my search for a 3.76 Aristo diff, I came across an ad for a 3.76 with an aftermarket Torsen installed. I had not heard of this before, so I contacted the seller to figure out where it came from. He ultimately directed me to a "Quaife Torsen-2 type" found here. Since Quaife never made a diff for the Supra, it looks like a third party used their design.
He was using it in a GS400, so I did not get any info about high power durability, but he was happy with how it performed. Unfortunately, the diff sold (in less that 1 day) before I could make a deal on it. I am interested in a Torsen over a clutch type for street use, but I am hesitant to use an OEM unit due to their history of failing under power.
^^ That link is VERY interesting. This is the first that I have heard of Quaife having designed one of their ATB differentials for the Toyota/Lexus 200mm casings. I'm hesitant on this and I think following up with Quaife corporate would be a good idea to be sure this thing is legitimately approved by them for use in our differentials.
I contacted Wavetrac Differentials some months ago about the possibility of one of their ATBs being made for the SC/Soarer/GS/Supra MKIV crowd. Their response was that they have noted some interest but there was nothing further beyond that.
JTEKT Torsen (owned by Toyota) actually made two of their LSDs for our common 200mm rear axles:
From 1990 to sometime in the late 90's they made 200mm compatible Torsen T-1's that use a spur gear and worm gear arrangement for the Soarer Z30, Aristo, Supra MKIV small diff models and (reportedly) Canadian SC400's. Those are the Torsen LSDs that you have heard about which have power holding limitations.
I've been running one of those T-1's for years and it's quite good, requires no service other than standard gear oil that the SC service manual dictates and pretty much does what it's advertised to do without any hassle.
The Torsen T-1 limitations are: no preload so if one wheel leaves the ground it temporarily becomes an open diff (since there is no torque for it to mechanically bias), does take some care to drive in the rain with no additional traction control system (but performance tires with good rain traction characteristics helps this tremendously... and this is a common thing with all mechanical LSD equipped car that have no extra traction control system).
And at 500whp the limit of its ability to safely and reliably bias power between the two axles and HOLD that much horsepower and torque is at its edge. Some people have more luck than others but the consensus is that another design LSD is in order if someone is pushing that much power. The Torsen T-1's are not ideal for drag racing cars due to the extreme shock loading on those spur gears and worm gears.
However the T-1's are excellent road racing and general technical driving since they are 1.5-way. They are excellent for street cars that are below 500whp. I can attest to this (300-350whp daily driven SC with a Torsen T-1). For dedicated road racers a superior upgrade from a Torsen T-1 LSD would be the OS Giken 1.5-Way LSD.
Additionally Torsen also made a T-2 (not a T-2R, just a regular T-2) for our 200mm diffs as well.
In the USA I believe these only showed up in very late model 1997-1998 Supra TT Automatics (smaller 200mm diff type) and some 1997-98 Supra NA's (same smaller 200mm diff type). In Japan these 200mm Torsen T-2's were available in JDM Supra MKIVs (small 200mm diff and also the big 220mm 6-speed diffs), JDM 1996+ Soarer VVT-i's and JDM 1996-97+ Aristos.
These T-2's use a different internal design that is stronger and overall superior to the T-1 in many aspects. The general design approach is also similar in modern Quaife and Wavetrac ATB gear-type limited slip differentials.
SC/Soarer/Supra/Aristo Torsen T-2's are much harder to find in the U.S. than more common Torsen T-1's. Also, many people don't make a distinction between the two. That could just be because they're rare in general.
....
Back to that Ebay ad for the "Torsen-2 Type ATB LSD..."
I'm going to take a guess and say that since the seller isn't all that specific in the ad (or rather it's hard to tell) this is actually referring to an OEM Toyota Torsen T-2 from a late 90's or early 2000's Toyota Aristo, Supra or Soarer.
This would make the most sense. But also the shape of the one pictured in that ad... I'm not quite sure that's what the general LSD shape for our 200mm diffs conforms to. I could be wrong but it definitely doesn't look like a Toyota OEM 200mm Torsen T-1 or a T-2. And I've seen both.
To date the only aftermarket LSDs that I am aware of for our cars are clutch-type models by: TRD (discontinued, 2-Way), Kaaz (2-Way), Cusco(?) (2-Way), and OS Giken (1.5-Way and 2-Way available).
And the only two gear-type ATBs available are used OEM Torsen T-1's and T-2's.
...
In general though if you are building an SC that will have less than 500whp and isn't going to be thrashed as a drag racing car you should have no concerns about using a Torsen T-1 LSD. I quite enjoy mine and it's very reliable and durable at and above my power level. Handling and even acceleration is much improved with it. Nothing not to like.
A Torsen T-2 is, again, an overall improvement and strength improvement over the 80's-ish T-1 design. All the Torsen LSDs that modern Toyotas come with from the GT86 to high performance Lexus models are T-2.
This link explains the difference between the three Torsen variants (the T-3 is only ever used in AWD/4WD center differential applications):
These seem to be made by a Russian company called JRP. There is no information on it other than the fact that the diff is supposedly brand new and is made by a company that otherwise is known for making Jet Ski equipment. They seem to make several LSD's for many other cars. It is tempting, but you just never know what you will get. I cannot find any other information of other people running their LSD's...
I have never heard of them before and honestly all of that sounds extremely dubious to me. It doesn't even look like the correct shape in the ebay picture.
I believe it is a Quaife ATB clone. It looks like a Russian company reversed engineered the Quaife unit and used the same design to fit our Supra/SC diffs. Like you said mrm, I can't find any info about someone using one. I would be willing to try it out at stock to low power levels, but using an untested or unproven Torsen at higher power is concerning.
I believe it is a Quaife ATB clone. It looks like a Russian company reversed engineered the Quaife unit and used the same design to fit our Supra/SC diffs. Like you said mrm, I can't find any info about someone using one. I would be willing to try it out at stock to low power levels, but using an untested or unproven Torsen at higher power is concerning.
If you do decide to test it out, I'm sure several of us here would be interested in the results!
Funny you guys mention this, i just received my Russian diff today! My concern is the bolts holding it together look a bit soft, like they were rounded ever so slightly. That and they do not have lock washers, so i may remove them and buy better hardware and use lock tight.
Otherwise shipping was crazy fast, i ordered apr 1st lol.
Don't know when I'll install, gotta collect a few more parts yet
I’m also curious - personally I’d go torsen over the disc type KAAZ I installed. However, they’re usually too damn expensive that I couldn’t justify it.
CRASHMONK, wow! So this is real after all! I'm also interested to see how this will work out. The conical tapering at the bottom on on one side is what throws me off visually when compared to other differentials made for the SC/Soarer/Supra/GS/Aristo. It tapers down more like one of our open differentials (visually) rather than any of the LSDs I've seen for our cars. But that could be meaningless as other LSD designs have a taper also. The OEM Toyota side carrier bearings fitting on there with proper clearance (and the right thickness Toyota shims) is all that will matter for installation.
What that visual difference may point to is that this may not be a reverse engineered duplicate of a Toyota 200mm Torsen LSD but rather some other gear type ATB LSD design sized and adapted for our pumpkin type.
I agree with you about the bolts holding the diff together. I'd hope they used some Loctite Red on those but how would we know? They do not look like the kind of bolts you'd normally see on a differential and the lack of locking washers might also be of concern. Hard to tell what grade of bolts they are. Even OS Giken sells somewhat similar looking bolts for their multi-disc clutches with integrated flywheels where you'd normally expect something that resembles an ARP bolt.
The main concern I'd have is not knowing what torque the manufacturer wants on each of those bolts. Is there any way to contact them and find out? Or does it say so in a manual for this diff?
Also was there any mention by them of needing to use one particular axle stub part number (from Toyota) in particular? Some of the other well known SC300 LSD manufacturers including OS Giken require that certain length 200mm SC/Supra/GS/Aristo axle stubs be used for proper clearance with their LSDs. Others don't specify this as a requirement.
If it's a gear type I'd expect it would run on standard SC diff oil (75W-90 GL5) unless they want some other oil type or weight in there.
I'm very interested to see and hear about the result of this as well!!
So i asked the vendor about the bolts, says they are lock tighted in. Also mentioned voiding the warranty should i remove them to check... so, i will continue to install as is. Everything seems to check out so far, ring gear goes on nice and tight, bolt holes line up perfect, cv splines seem to engage far enough for the clips to pop out and hold the shafts in place.
There is a bolt and nut type of thing in the center that's loose and just flops around. I think it's there to hold the unit together while the bolts are put in place, helical lsds are usually assembled with some preload. So I'm not too concerned about that either.
Just gotta remove these bearings and press on to the lsd, then we can move forward with the install
So i asked the vendor about the bolts, says they are lock tighted in. Also mentioned voiding the warranty should i remove them to check... so, i will continue to install as is. Everything seems to check out so far, ring gear goes on nice and tight, bolt holes line up perfect, cv splines seem to engage far enough for the clips to pop out and hold the shafts in place.
There is a bolt and nut type of thing in the center that's loose and just flops around. I think it's there to hold the unit together while the bolts are put in place, helical lsds are usually assembled with some preload. So I'm not too concerned about that either.
Just gotta remove these bearings and press on to the lsd, then we can move forward with the install
Do you have a Instagram or Snapchat where I could stay more updated? I seen that diff for sale today and when I looked up the part number this thread appeared. So far I’m debating ordering it.
04-09-20, 06:48 AM
Aftermarket Torsen
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