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cheap junkyard LSD?


Wiggilez
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I remember hearing something about this a while back. Any info on years and models to look for?

 

They have a three part series on it, and I believe in the second one they say either a 240 and some other one, but can't remember off the top of my head.

 

edit, they also state that models that are turbo with auto trans and towing package will have a diff capable of 4.10 gears.

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  • 3 weeks later...

Are these clutch-type diffs that eventually need to be rebuilt or some other type?

 

Indeed these are mechanical. Torsen design, no friction discs. I am not familiar with their durability/toughness but after doing several hours of research and watching some videos i must say i am deeply intrigued with how they work. They are hella complicated.

 

Unlike a typical LSD that utilizes springs to apply pressure at all times and begins to slip as greater torque is applied, the torsion design acts as a fully open diff under normal driving conditions and "locks" once significant slippage occurs on one side or the other. I think this design is really really awesome, for the simple fact that some engineer figured out a way to divert power from a slipping tire to a tire with traction using only mechanical principles.  

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Well I bit the bullet and got me an lsd from a volvo 940 set for 4.10s....

 

 

 

Please please please, let us know how the install goes. I am VERY interested in doing this myself.

 

This is my plan. . .

 

Volvo LSD (4.10s)  +  a ford 8.8 (LSD, disc brakes, 4.10s) = super cheap super capable offroad combination.

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Indeed these are mechanical. Torsen design, no friction discs. I am not familiar with their durability/toughness but after doing several hours of research and watching some videos i must say i am deeply intrigued with how they work. They are hella complicated.

 

Unlike a typical LSD that utilizes springs to apply pressure at all times and begins to slip as greater torque is applied, the torsion design acts as a fully open diff under normal driving conditions and "locks" once significant slippage occurs on one side or the other. I think this design is really really awesome, for the simple fact that some engineer figured out a way to divert power from a slipping tire to a tire with traction using only mechanical principles.  

 

Actually, the Torsen is fairly simple in principle.

They're set up the same way as a typical open differential, only they use helical gears against a worm instead of the traditional spider gears. This ends up working like a worm drive in that you can spin the screw part and it'll turn the worm gear, but you can't spin the screw by turning the gear. Because of the helical cut of the gears in a Torsen, you do get some "backwards" movement, which is what allows it to function as an open diff, but you can't get huge differential wheel speeds because the gears will bind.

It also doesn't lock, ever. It's only a limited slip, and the amount of power it can send to the wheel with more traction is a function of the amount of resistance (i.e. traction) at the other wheel. That means that if you lose traction completely, say by picking up a wheel, it can't send much power to the other side... but a gentle application of the brakes will fix that.

 

There's a lot of info out there on how they work, and a lot of it is pretty well engineering reports explaining all the minor details of this and that, and the rather beautifully simple bigger picture of how the unit does its thing tends to get lost in all the focus on torque bias ratios and preload and other mumbo-jumbo.

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