Nissan 370Z Forum - Limited slip, worth it?

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- - Limited slip, worth it? (http://www.the370z.com/engine-drivetrain/13213-limited-slip-worth.html)

Quote:

Originally Posted by j.arnaldo (Post 367958)

Thanks, ChrisSlicks! Is that the same as PosiTraction?

PosiTraction was a trademark name used by GM in the 60's for the LSD they were putting in their vehicles.

the lsd will heat up even on straight lines. mine did (along with another nismo) and for a good 30 minutes or so, won't go forward. admittedly, I didn't "break in" my car when I drove a sustained 140mph. how breaking in would affect the lsd unit? I don't know.

I just replaced the oil and it's been good so far.

The sport package is totally worth it. For ~$3000 more, you get syncro revmatch, 19'' wheels w/ tires, bigger brakes, VLSD, front lip, and a rear spoiler.

Aftermarket wheels and brakes will cost you that alone!

Quote:

Originally Posted by ChrisSlicks (Post 360393)

Torque sensing differentials can do that (Torsen for example). The Viscous unit uses perforated discs, rotating in fluid. The discs are stacked such that they alternate for the 2 output shafts, so when one axle is going faster than the other it will generate a hydraulic force against the other to speed up the slower axle. Unfortunately as the fluid heats up it loses it viscosity which makes the whole system ineffective.

Just curious. Since viscosity is a major factor for the stock LSD. Would it be safe to say changing the fluids every so often will keep from failing? Like oil changes. Maybe go with a thicker fluid.
Also with the stock sport LSD, does aggressive gear shifts in straight line driving effect it? Or is it only cornering? Some Z's that are FI can wear out te stock LSD with aggressive off the line starts fast right? Thanks.

the fluid that fails in the stock lsd is the silicone fluid inside the sealed cartridge in the ring gear carrier (a little can in the very nuts-center of the diff) changing the 90w fluid will only keep the gears and bearings feeling happy.

Torsen, positraction, quaife are all the same helical type units with very minor differences, that use inter-meshing worm gears instead of the tradition cone shaped spider gears (the little ones inside the ring gear carrier) that due to torque differences between the two wheels are capable of sending a ratio of of torque from the wheel with the least traction to the wheel with the most traction provided that both wheels have some traction = if you lift a wheel or are in snow it acts like a one wheel wonder.

Clutch and viscous types work on rpm more than torque so if one wheel is spinning faster than the other, it starts locking. If its a really touchy clutch type it means it won't want to turn a corner at slow speed which makes parking lots a pain (properly set there are clutch types that don't do this that much). The reason a viscous doesn't do this is because instead of having friction plates it just has smooth steel plates spaced close together with a bunch of holes in them, and a thick silicone goo that when spun fast enough (one wheel starting slipping crazy) the molecules of silicone work like shoving a stick in between all the holes locking them together. Trouble is the silicone goo is unpredictable and gets crazy hot and either just dies and does nothing, or if you're really lucky blows it's little case up trashing your diff.

to the guy that thrashed the hell out of his car leaving the dealer and it "wouldn't go forward" don't be pointing fingers at the viscous it does virtually nothing in a straight line (unless you were doing a sustained 140mph powerslide) and if it died wouldn't effect the way the car drove really so you either F'ed a bearing right in the A, or something. Was it snubbing wouldn't go forward, or was the motor running and it just wouldn't go forward?