who has done it? is it even possible? tips for getting a good gear pattern? worth it for low traction driving ie rallycross/ice racing?

also what is the difference between LSD and VLSD.

also opinions on welded rear diff in a 5mt car for rallycross?

which is the better LSD I should use for this? what to find it in?

I'm not exactly what you're asking, or for what car. but I do know that many newer subarus came with 4.11's and a rear LSD stock. Forester XT's I think....

 

the reason we don't do it to our older gen cars is the front diff is completely different, and, thus-far, there is no way to get the 4.11's in the tranny, therefore a rear 4.11 LSD is worthless

 

that being said, I have a clutch-type EA82 rear LSD converted to 3.9 to match my tranny, and it's AWESOME in almost any condition, the only time that it gave too much slip, was when I had one rear wheel about 3 feet in the air, in a 'ditch' so I couldn't pull myself up the next hill, but I jockeyed the car and it pushed right up it....I've heard the viscous ones aren't as tight in an offroad application like that one, but might still work well for rally/iceracing

sorry, should have been more clear. I have a 1991 legacy with 4.11 5mt trans. I want to put an LSD in the rear diff. 4.11 LSD is a JDM deal only, so I want to use the far more common(and cheaper) clutch type in my car which as far as I know came with 3.7 or 3.9 gears.

basically what I want to know is, is it better to swap gears to the LSD diff or swap the LSD guts to the 4.11 diff? I would rather do the LSD swap to my gears to avoid having to set a gear pattern which I dont feel comfortable doing just yet. or if you have experience in setting up diffs tell me a step by step.

also, are there rebuild kits and replacement clutches in the even that the diff I find needs a rebuild?

You can use any rear r160 clutch type lsd with your 4.11's

oh, yep, if you get an LSD carrier from another subaru, I bet the swap would be virtually identical to what we old-gen people do all the time. check the repair manual for the write-up

oh, awesome! I never even looked at that part of usmb. thanks all.