posi vs lsd?

**NE98LS1** · 02-19-2006, 08:47 PM

what is the difference between posi and an lsd? i don't really understand either, and not sure what my 98 TA wouldve come with?

**oneBADDz** · 02-19-2006, 08:55 PM

true posi has no slip whatsoever, both axles pull equally all the time. LS allows one to turn a small amount before locking them both together into posi style. It makes for smooth turns. With a true posi you have one wheel hopping in turns due to the different speeds they need to travel during the turn.

**NE98LS1** · 02-19-2006, 09:51 PM

what do our cars have? or is that an option code i'd have to check out?

**ss~zoso~ss** · 02-20-2006, 06:15 AM

our cars have LSD's limited slip differentials, i'm not sure of the code, i have it somewhere

**19691998firebirdtransam** · 02-20-2006, 07:14 AM

A posi and a lsd are the same thing.

Your 98 T/A came with a LSD.

You have three types of differentials, basicly...

1. Open differential = non performance applications, one side or the other transfer torque(spins)

2. Limited slip differential. = Posi is a slang word for limited slip (lsd), the words are interchangable. A limited slip will be one of two types, clutch or cone, either style works fine, the clutch style is easier to rebuild. A limited slip needs a friction modifier added to the lube to prevent chatter/clunking. A limited slip will spin both sides equally until something evercomes the clutches/cones, like taking a sharp corner. If it is working properly, you will never know it is slipping, thats the way it was designed.

3. Locker = A locking differential will transfer torque to both wheels through mechanical design, the detroit locker will unlock during sharp corners, it ratchets and clunks very loud and noticable. Off road enthusiests use air lockers, which are on demand differentials. Just turn them on when off road and get torque to both wheels.

**Qwk94Z28** · 02-22-2006, 08:57 PM

Z driver one said it in simple terms, 1969..... said it almost out of a book lol.

depending on what your cars main use is, prolly daily street ect. i'd go lsd

**19691998firebirdtransam** · 02-23-2006, 01:39 AM

NE98LS1 asked what is the difference between posi and an lsd?

There is no difference, they are the same thing.

**keliente** · 02-23-2006, 08:52 AM

I'm with him ^....LSD = posi

**oneBADDz** · 02-23-2006, 09:14 AM

In my opinion a "locker" is the same as a limited slip and a posi in locked together all the time. Why would it be called a locker if it was always locked? The name implies that it isn't always locked and it locks. Either way, his question was answered and terminology isn't exactly the important thing. Most old school guys call it a posi anyways, back in the day you had single trac and posi, no limited slip

**mrr23** · 02-23-2006, 05:29 PM

Originally Posted by z_driver1

true posi has no slip whatsoever, both axles pull equally all the time. LS allows one to turn a small amount before locking them both together into posi style. It makes for smooth turns. With a true posi you have one wheel hopping in turns due to the different speeds they need to travel during the turn.

that would be callled a spool. not a posi. a spool locks both axles together basically making it one solid axle all the way across.

locker, posi, LSD (not the drug), posi-traction = all the same. locked together drive straight. unlocks so the wheel on the inside of the turn will free spin.