can you convert an open diff to a lsd?

[Andy348]

To add to the OPs question, what are the difference in diff cases? Such as medium diff lsd, etc.

Sorry for the thread jack :p

[call me jack]

I know that. But on lsd's as soon as your on the throttle and giving it power it locks up and becomes the same thing as a spool. the only difference between the two is that the spool is locked 100% of the time. The lsd is locked when your on the power and un-locked while your coasting. If I wasn't able to get ahold of an lsd for free, I would have welded the diff that was in my 318i. The main thing is how will he be driving it? When you answer that then you will know which setup will work best.

yeah, but my mullet isn't quite long enough to do do that, yet.

on the note of welding in a diff, i'm going to thread jack my self, and ask; has any body had the need to weld there planetary pin into place? the guys on the saturn forum do that to keep from ripping holes in there transaxles (don't ask why i was on a saturn forum)

[crazyman]

You'll be hard pressed to find a limited slip diff that truly locks up 100%. What use would they be in corners if they did?

If you've ever driven a vehicle with a spool rear end, you'll know they are not happy things in corners, and can be somewhat unstable in a straight line. They force the tires to become the differential.

What you really want is a differential that will put torque to the ground in the widest range of operating conditions. A welded diff / spool probably has the narrowest range of useful torque application on paved surfaces in the motive sense.

I have driven a few trucks with a spool, and the ford I own has a welded rear end, and there 3/4 and 1 ton trucks. while driving them I've never had any issue's with being unstable in straights, and issues cornering. The only difference I've noticed is doing tight turns in parking lots, it tends to push a little more than usual.

[u3b3rg33k]

With a spool, if you have one tire wear faster than the other (it happens), its circumference gets smaller, and the vehicle will want to turn towards that side, or it will scrub one of the tires constantly. A diff will handle it much more gracefully.

Figure, if a tire slips one full revolution per mile, at highways speeds, that's a significant amount of wheel slippage. Best case, tire wears faster; worst case, tire overheats or fails prematurely.

There are just so many good reasons not to run a spool on a street/track vehicle. If you off-road or drift, it makes more sense.

[crazyman]

With a spool, if you have one tire wear faster than the other (it happens), its circumference gets smaller, and the vehicle will want to turn towards that side, or it will scrub one of the tires constantly. A diff will handle it much more gracefully.

Figure, if a tire slips one full revolution per mile, at highways speeds, that's a significant amount of wheel slippage. Best case, tire wears faster; worst case, tire overheats or fails prematurely.

There are just so many good reasons not to run a spool on a street/track vehicle. If you off-road or drift, it makes more sense.

Yeah I see your point. But if you drive like I do, the rear tires would wear out long before that ever happen, LOL. I do like to drift and do that stuff in both my Ford and BMW. Basically again it all boils down to application, for which one will work best.

[call me jack]

like i said; my mullet just isn't long enough.

[u3b3rg33k]

like i said; my mullet just isn't long enough.

Well then check out the FS section. Plenty of medium case LS diffs up for sale.

You'd have more fun if you picked up a Z3 torsen unit though :twisted:

[call me jack]

Well then check out the FS section. Plenty of medium case LS diffs up for sale.

You'd have more fun if you picked up a Z3 torsen unit though :twisted:

oh? can you elaborate a little further? i know nothing out this "z3 torsen unit"

[u3b3rg33k]

Instead of a clutch pack, it's basically this on the inside:

http://www.torsen.com/files/Torsen%20T-2%20Technical%20Sheet.pdf

A non-M Z3 rear end will bolt up directly (same rear end as the e30), no clutches to wear out, and in my experience / opinion, better than a used LSD. Couldn't say how it compares to a NEW / rebuilt LSD, But I do know that mine's all kinds of fun.
They're fan-freaking-tastic in the snow, whereas I've had issues with not being able to put down enough torque with a clutch pack for it to lock up when on ice. The torsen lets me cheat.