High lock diffs

[Ian Bowers]

I just wanted to update: I purchased 3 Bimmerworld "race" clutch discs, and an extra porsche 2.0mm plate. My bud put it together and modified the ramp angle so it's around 60-65% lockup.

It's. Fucking. Amazing. It honestly changed the way the car drove. It is more predictable, more stable, and much more communicative. I love it.

[Wanganstyle]

Just remember, don't just shove in extra clutches. You need to machine if you go more than 3 clutches. Otherwise, you might as well just weld the damn thing.

Where do you know this from? I have a 4 disc in my car, no machining required. You can drive it if you are local

[guibo09]

this thread makes me happy i took the time to swap a z3 lsd into a 4.11 pumpkin.

[FredK]

Sure. So you'll have a 75% lock diff?

[Jean]

Not doing different ramps at this time, it adds up another $$$ on top and I don't want to make too many changes at once to evaluate the results...

[samiam3356]

^^Thinking of doing this on my next rebuild. Want to add at least on more clutch and might go up to the 2.1mm plates.

[FredK]

Are you getting new ramps cut?

[Jean]

I'll leave that to the pro to do :)

[shiboujin]

Just remember, don't just shove in extra clutches. You need to machine if you go more than 3 clutches. Otherwise, you might as well just weld the damn thing.

[Jean]

4 new oem clutch discs have been ordered overnight :) If all goes as I planned I'll have my center section out this friday/saturday for a build.

[328ijunkie]

My customer diff building pictures for all to enjoy:

https://picasaweb.google.com/davewmarkert/DiffBuilding#

[Wanganstyle]

Well, if any of you come across a 3.91 viscous diff out of a manual IX, shoot me a PM and I'll try it in my car and the drift car.

you should try to shim it before install, if you drift it as is it may die very quickly....

VLSD hates drifting :) but we do it anyway!!!

[JakeP]

Well, if any of you come across a 3.91 viscous diff out of a manual IX, shoot me a PM and I'll try it in my car and the drift car.

[u3b3rg33k]

But this isn't oil. And there isn't anything wearing/rubbing, is there?

Just because it's a liquid doesn't mean it can't change state.

Take a butter churn as an example. I don't see any friction, but it still turns milk into butter. Look into shear forces in fluids - that has an effect on molecules.
Heck, i just found your friction. Molecules rubbing on molecules.

[Wanganstyle]

Because you have friction and contaminants from metal on metal contact in the S54. In the viscous you only have silicone on metal... very, very little wear on the metal if any.



Agreed, in friction-clutch style LSD. And in the torsen you just have gears, producing very little wear in comparison. But I don't see how the viscous diff would wear out. Maybe if you overheat/cook the fluid (happens when an IX gets towed with only the rear tires on the ground).

I'm no viscous expert, never torn one down before.

Perhaps research this subject of how viscous breaks down on nissan drifting forums and report back to us?
I have a list of friends who have cooked their OEM Vlsd units in 240sx's - I'm not sure if they know or care how it actually works, they shim it and go back to drifting or junkyard another J30 VLSD!!

Most likely the fluid is broken down due to heat; perhaps if you were able to open up the sealed unit and replace the Viscous Fluid with a higher temp fluid it would stand more abuse. If there is a similar shim part to the nissan setup then perhaps one could shim an IX VLSD to be slightly more aggressive than a stock unit.

for lap time use or drifting, a properly configured clutch diff would be the ticket. For street + track; Torsen.