KahnBB6

iTrader: (5)

This has been covered before at least in some LS400 threads. Very old open diffs in these cars can occasionally exhibit some characteristics of an LSD but it has more to do with the bearings being worn and just being a bit lucky in terms of the situation. If you know the car's history and it was stock when you bought it there is no Torsen in there but the scenario you describe has happened before.

If you were to go drifting with your SC the differential would not react as if it had an actual LSD but doing burnouts and getting two strips is technically possible with an open diff under the right conditions. Replicating those conditions over and over is near impossible on a consistent basis.

KahnBB6

iTrader: (5)

I have a 93 SC (which until recently had the) original W58 5-speed with the same stock open diff as yours (4.083). The TT Auto Torsen 3.769 pumpkin will drop into any 92-00 SC300/400 but you would want no less than the gearing you already have or a 4.272 ratio (same as 93-96 Supra NA W58's). The 3.769 ratio will work but will totally kill your car's power delivery unless you're immediately going with an engine swap or NA-T build.

The absolutely direct drop in diff is an ultra-rare Torsen diff pumpkin from a 93-96 Supra NA (4.272 ratio) or 97-98 Supra NA (4.083 ratio). It's the same thing as a TT Auto Torsen pumpkin just with an NA ratio. Extremely hard to come by.

What I did was buy a 94 TT Auto Torsen pumpkin and a GS300 4.27 pumpkin and had Driftmotion rebuild the TT pumpkin with the 4.27 ratio. I kept the 3.769 TT ring and pinion for future use.

It's all tedious but it's worth it in the end.

LEXXIUM

iTrader: (1)

I'd have to look into it for sure to tell you, but I wouldn't buy the 6speed LSD, because it wouldn't fit our pumpkins, they use different housing.
Edited
Ok you're right hmhatch, it is a 6speed rear end, I just went back to see my ebay history, ok I did say they wouldn't fit, that's with 6peed ring gear

3L4jzz31

iTrader: (2)

12 holes on the outer ring is 6 speed diff
10 holes is from auto TT or N/A 5 speed

This link can answer most of the future diff questions as far as ratios


http://www.supraforums.com/forum/sho...ferential-Info!

lsc4

Any one notice or confirm this from the link (2nd post)?

*Canadian market SC400's came with a Torsen LSD - US spec SC400's did not.

3L4jzz31

iTrader: (2)

It was based on some guy having an lsd in his sc400 when the previous owner said he did no modifications. He never prooved that he had one but they took his word on it and put it in there

RUSSIAN300

Has any one attempted to install a Toyota CHASER 10 bolt Torsen into an SC300 or 400 case, and if it has been attempted does the Ring and pinion work with this set up?
Ive found some info here but still got questions, if you have done this or there is a write up on the subject please feel free to answer this with a link to the info, also my HP goals for this particular car should not be excessive for a torsen, its a daily driver and it is an NA auto, and will stay that way for some time.
Thank you for all of you responses.

KahnBB6

iTrader: (5)

I'm afraid that's not going to work, sorry. Toyota Chasers, Mark II's, Verossas, etc. all sharing that same sedan platform all use the common differential internals that go all the way back to the MKIII Supra, USDM Cressidas, IS300 2001-2005 generation, the IS250 2006-1012(?) generation... and... with significant external differences... the the Toyota 86 / Subaru BRZ / Scion FR-S.

The Torsen T-2 LSD from the early IS300, all those Chasers/MarkII/Verossas and all the Toyobaru coupes are great LSDs and are still in production and available to buy new... but they are not the right dimensions and specs to fit our differential casings.

There were Torsen T-1's and from MY1996 onward Torsen T-2's made for the common 200mm/8.5" Lexus SC / JDM Soarer Z30 / Supra MKIV / Lexus GS / JDM Aristo differential pumpkins but they are much rarer than the one you are looking at. Supra MKIV TT Auto & MKIV Supra NA 200mm Torsen T-1's in the USA are far more common than the 200mm Torsen T-2's that are more plentiful in Japan but which were only available in USA-spec Supra MKIV 200mm diffs for 2-3 model years (1996-1998 for the USA).

If you are planning to stay NA and automatic you will not be stressing a Torsen very much. You DO need to get a shop that knows what they are doing to install any differential into a 200mm SC pumpkin so that the ring and pinion engagement is within spec and so that the side shim measurements are spot on within spec. Driftmotion sells a complete Toyota 200mm SC/MKIV/GS diff rebuild kit using all OEM bearings and seals. The OEM side shims are to be measured by your driveline specialist and the very specific side shim size is then supposed to be ordered from Toyota (it really comes down to how the measurements work out for a particular diff).

But unless you plan to floor the car all the time and drag race it, as long as the used Torsen's internal worm gears and spur gears do not have any play that would be of concern to your driveline technician (they should always be inspected if installing) it will be fine at least until 450-500whp before they become less predictable. Technically they are "lifetime" mechanical LSDs at horsepower levels significantly below those figures and especially when used in NA cars or stock boost or maybe simple BPU boost cars but they can technically wear out after hundreds of thousands of miles of use depending on how they are treated over their lifetimes.

They are Toyota approved parts after all so... unless taken FAR outside of what even Toyota considers normal durability range they will last a very long time.

With the T-1 Torsens the thing that primarily harms them is repeated shock loading (ie: drag racing) and, at a certain point, very high horsepower (really torque) that overwhelms both their internal gears strength and their ability to bias power effectively. The rarer T-2's have a different design, relying only on internal worm gears with no spurs and are said to be stronger. But again... with an NA or very low power turbo SC you're not going to harm a Torsen T-1 outside of drop clutch drag racing.

I had your same concerns when I bought my Supra TT Auto Torsen T-1 LSD pumpkin years ago. My car was staying NA at the time (though manual). I had the diff rebuilt with a 4.272:1 ring and pinion ratio. I was assured that the low NA torque was well below its limits and this was my experience for about eight years running that setup.

Even with my current setup at 300-365 ft-lbs coming on low in the rev range it's still not going to harm my Torsen T-1 unless I start driving like a moron and drop clutch drag race the car all all the time (ie: deliberately shock load the Torsen). For that kind of driving with my SC I would be better off getting an aftermarket clutch type LSD but I daily drive mine and don't race it so its unnecessary at this time.

All Torsen T-2's regardless of the vehicles they go into are better at handling big(ger) power but for the big horsepower numbers some people build for it just makes more sense to go with a clutch type LSD for reliable power holding, predictability (at those high power levels) and safety.

The only general thing I recommend with a Torsen equipped SC is to consider alignment specs close to an MKIV "Lance" alignment if you have an MKIV style rear swaybar swap... and also good summer high performance tires that have notably good rain traction reviews when used on other popular performance RWD vehicles.

If you can find either version 200mm Toyota Torsen it will be worth it certainly and very suited to your lower power/torque level. But they are somewhat difficult to find for sale.