New source of Torsen T2 LSD's

Jeff Lange

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Mar 29, 2005
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I know some people have used the IS300 Torsen T2 in their MA70, and I just thought I'd share that there will likely be a more plentiful and potentially more common (though expensive at first probably) source for them in the new Scion FR-S and Subaru BRZ. Both of these are going to be equipped with the same LSD. :)

Jeff
 

te72

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Mar 26, 2006
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I was always under the impression that Torsen diffs behave great, UNTIL you approach the limit of the inside tire, then you have a 1-way diff. Am I mistaken there? If not, why would one want to switch from a clutch-type to a Torsen? Better response perhaps?
 
Oct 11, 2005
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I think you a re referring to the problem where the inner tire is airborne, then you have a problem because the TBR is usually only around 3 or so, and 3 x ~0 = ~0....

[wikipedia]
When a Torsen differential is employed, the slower-moving wheel always receives more torque than the faster-moving wheel. The Torsen T-2R RaceMaster is the only Torsen to have a preload clutch. So, even if a wheel is airborne, torque is applied to the other side. If one wheel were raised in the air, the regular Torsen units would act like an open differential, and no torque would be transferred to the other wheel. This is where the parking brake "trick" can help out. If the parking brake is applied, assuming that the parking brake applies even resistance to each side, then the drag to the airborne side is 'multiplied' through the differential, and TBR times the drag torque is applied to the other side. So, the ground side would see (TBR X drag torque) minus drag torque, and hopefully that can help restore progress either forward/backwards. In Hummer/HMMWV applications, there are both front and rear Torsen differentials, so the use of the main brakes will operate this "trick" on both axles simultaneously.
 

PureDrifter

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(very) generally speaking:

torsen=better for circuit driving/mild autocross/mild drag
clutch type (1.5 or 1way, ala turbo stock lsd)= better for drag, good for autocross/gym/beginner drifting
clutch type (2-way)= best for drifting (arguably), not well suited for circuit driving.
spool/welded diff= good for drifting, sometimes good for drag.

I'll probably be looking for an IS300 torsen at some point.
 
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1StTurbo

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Does anyone have a picture of the inside of a Torsen? I am trying to see if that's what i really have or another stock LSD
 

Zazzn

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Apr 1, 2005
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Hrm, sorry to bring this up from the dead, I'm about to have the Wier Max performance kit added to my LSD, but now seeing this I'd MUCH rather a torsen, as I do very limited drag racing in my mk3 and more less I love LOVE LOVE the way torsens drive day to day. Does the FRS Torsen unit work in the mk3 and is it a fairly simple swap? Does it hold up to power?
 

shipkiller

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Zazzn;2089765 said:
Hrm, sorry to bring this up from the dead, I'm about to have the Wier Max performance kit added to my LSD, but now seeing this I'd MUCH rather a torsen, as I do very limited drag racing in my mk3 and more less I love LOVE LOVE the way torsens drive day to day. Does the FRS Torsen unit work in the mk3 and is it a fairly simple swap? Does it hold up to power?
weren't you the one who convinced my cousin to buy that IS200 pumpkin for my mk3 diff?
 

Dave 1jz

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Feb 16, 2010
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Yes the GT86/FRS fits the Mk3 differential housing. Plus the great benefit is that the shorter LSD stub axles fit. With the original T1 torsen, the 10mm longer stub axles are required and are hard to get hold of.