dddddyang

Hi, I have an open diff on my car. Every time i do a burnout i get one wheel spinning only. I'm thinking getting something to fix that. Should I get Limited Slip diff or should I get locking diff? What's the difference?

oldcutlass

A limited slip uses clutches to slip the posi unit during turns when one wheel slower than the other. A locker has a mechanical device that locks the axles to one and other. Some lockers are pretty noisy in turns, and spool types are not conducive to having good street manners.

Fun71

Some lockers are locked any time there is throttle applied, so making turns causes the inside wheel to slip, same as a spool. This can be VERY dangerous on wet / icy roads.

I vote for LSD over locker.

What car, and what rearend does it have under it currently? Some rears have a much larger selection of posi carriers than others.

MDchanic

When I was younger, I always chose the LSD when it was offered.

Oh, wait. You're talking about differentials.

Same advice. A lockup rear will make for a car that's only fun to drive straight ahead.

- Eric

dddddyang

1972 Cutlass Supreme. Don't know the current ratio yet, but imaging something 1:3-4 ish. I don't need it to be locked at all times, just want it to be able to spin both wheels for burnouts instead of only one. So LSD?

dddddyang

Not trying to make a 7min nurburgring car, but at least spin both wheels for burnouts.

MDchanic

Yes.

- Eric

dddddyang

Any recommendations?

MDchanic

Put up a want ad here for a limited slip rear, probably around 3.31.

You could use a '68-'72 rear from a different Division, if you want, but you may have to change the driveshaft, as there are several different ones, and they may have a different length at the nose.

If you want to see about getting parts to install in your rear, contact Monzaz on this board.

- Eric

Qwik71442

http://www.jegs.com/i/Detroit-TrueTr...2A556/10002/-1

Fun71

Factory rear would be a 8.5" corporate 10 bolt rear, and parts for those are very abundant.
No such thing as 1:3-4 ish ratio. I think the standard no-cost rear in that year was 2.73:1 but could be 2.56:1.

If you are wanting lower gears as well as posi, I suggest looking for a complete rearend. If you are just swapping the carrier from open to posi, look for a factory limited slip differential. It's a lot easier to swap just the diff than it is to install new gears.