I dont want to be 1WD anymore!

[Dan Baldwin]

Wow, what a thread! I'll just add a coupla minor points:

 

To the original poster,

You HAVE 2wd. An open diff does drive both wheels. In fact, an open diff ENSURES that both wheels get EQUAL TORQUE! I have a video of my car doing a SMOKY 2-wheel burnout way back when it had the 3.36 open diff 8)

Problem is that both wheels always getting equal torque isn't what you want, 'cuz as soon as one wheel loses traction, the wheel WITH traction is limited to the reduced torque level going to the spinning wheel. One wheel in the air or on ice and you'll just spin that wheel. Thrust at each contact will be limited to the traction at the wheel with the LEAST grip. Spin the inside tire in a turn, and you lose DRIVE. What's happening is that while the TORQUE at each wheel is equal, all the POWER is going to the spinning wheel (power = torque * rpm).

 

Regarding "worn-out" clutch type LSDs, I'm still using mine after 8 years! Breakaway was ~18lb-ft when I installed it, and I've never shimmed it. Before I removed the rear sway bar it would spin the inside rear out of 2nd gear turns, but without the rear bar, no problems:) Even with NO preload you get clamping force from the ramps the pinion shafts are located in. As long as you can get *some* torque to the ground, you're generating clamping force.

 

My setup ain't exactly optimal, BTW. I'm lifting the inside FRONT out of corners! Looks cool and impresses the hell out of observers, anyway

[awd92gsx]

I was reading my JTR book awhile ago...in it (I'll get the page number when I get home) they say that LSD's aren't that noticeable on straight line accelleration, but, are very noticeable in turns...

 

That statement seems to defy logic...am I just not thinking correctly?

[JMortensen]

They're noticeable in straight lines if you're normally getting the one wheel peel. You won't anymore. But really most of the time you're driving in a straight line, theres not enough power going to the wheels to make them slip, so most of the time the LSD does nothing at all.

 

The reason they are usually more noticeable in turns is because the inside rear gets unloaded and spins much easier than if you were just going straight. So the car will accelerate a lot better out of turns with a LSD. Makes any car a whole different animal.

[CasperIV]

I'm proud of myself.... I read the whole thread in one sitting

[Guest bluex_v1]

I just want to see this thread "resolved" one way or the other

 

I'm just not following the 'mechanical advantage' explaination either. If you look at the right half of the gears vs the left half of the gears as two interacting systems, one has an inverse gear set on its side which will undo any mechanical advantage that was created on the input side.

 

The torque multiplication factor makes sense to me given that the invex gears ride on the journals, so the greater torque on the ring gear/carrier housing will push them harder and result in greater pressure between the invex gears and the housing, which gives you an increase in friction and therefore an increase in the torque bias ratio (or equivalent). I'm just suprised they wouldn't put a replaceable bearing or clutch type disk there that could be tuneable.

 

I think Jon has laid it out pretty thoroughly with respect to the torsen...can anyone illustrate any fundamental differences in the Quaife's design?

[opie]

Auburns don't wear out clutches, they wear out the case itself. Kinda like the gear driven LSDs. They are not rebuildable, so as they wear they get less effective and eventually you just take them out and throw them away. They also chatter really bad, especially the Pro series.

 

 

 

Jon

 

Aren't the posi units in my gtos (saf-T-trac for Pontiac) an Auburn style unit (8.2 housing)? Actually they are rebuildable by machining the housing slightly and insalling bushings (spacers). Not really what I'd recommend for a hybrid, but for numbers matching it's fine, so they are rebuildable. Replacing the carrier with another maker is better though.