I see what your saying although VLSD are fluid like diffs the more torque that is applied the greater the wear and tear because it is a silicone fluid that changes density from applied pressure. The greater the torque the greater the transfer of friction/heat which can decompose the silicon based fluid, and even the 2 disc's that are used for transferring the silicon fluid conversion to make it viscous. So the less torque applied the less wear and tear due to less friction/ heat that is caused between the 2 disc's and the silicon fluid (which is gel). When you use diff fluid such as a 80W90 it is a standard fluid used for both open and VLSD's to maintain the least amount of heat and friction between moving parts such as the gear and shafts.

 

I still cannot believe that there would be a significant difference in mechanical wear in the VLSD between KA based drivetrains and those found in JDM s-chassis cars, or USDM J30's. I agree that the silicon fluid would need to be replaced sooner, but if I where getting a VLSD I would replace that anyway. One of the biggest reasons why VLSD's are used so often in production cars is because they last so much longer then any other type of diff, and are much easier to service*.

*While researching this I came upon an interesting article on diffs at www.answers.com. It indicated that the silicon oil in the VLSD's used in some Mazda's is not replaceable. If that is the case with the Nissan/Inifiniti's then I would completely agree with you that VLSD's found in higher horsepower cars are going to be in far worse condition.

Below is a quote from one of the articles I was reading:
"The viscous type is generally simpler, and relies on the properties of a dilatant fluid - that is, one which thickens when subject to shear. Silicone-based oils are often used. Here, a cylindrical chamber of fluid filled with a stack of perforated discs rotates with the normal motion of the output shafts. The inside surface of the chamber is coupled to one of the driveshafts, and the outside coupled to the diff carrier. Half of the discs are connected to the inner, the other half to the outer, they alternate inner/outer in the stack. Differential motion forces the interlocked (though untouching) discs to move through the fluid against each other. The greater the relative speed of the discs, the more resistance the fluid will put up to oppose this motion. In contrast to the mechanical type, the limiting action is much softer and more proportional to the slip, so for the average driver is easier to cope with.

Viscous LSDs are less efficient than mechanical types, that is, they "lose" some power. They do not stand up well to abuse, particularly any sustained load which overheats the silicone results in sudden permanent loss of the LSD effect.[4] They do have the virtue of failing gracefully, reverting to semi-open diff behaviour, without the graunching of metal particles / fragmented clutches. Typically a visco-differential that has covered 60,000 miles or more will be functioning largely as an open differential; this is a known weakness of the original Eunos Roadster sports car. The silicone oil is factory sealed in a separate chamber from the gear oil surrounding the rest of the diff. This is not serviceable and when the diff's behaviour deteriorates, the VLSD centre is replaced."

 

Bingo you hit it on the button VLSD are factory sealed you can't touch the silicon fluid that is with in the VLSD. 80w90 lubricant keeps the parts around the vlsd maintained and cooled. Oil works excellent as a cooling agent, so as long as oil changes are maintained the diff should outlast. Now what you researched also was the longevity as the more pressure is applied the faster it can wear and tear as more toque is applied the silicon oil burns and is no longer usable.

 

Thank you for enlightening me. I was planning on picking up a VLSD because they can be had for so cheaply. Now that I know that the silicon oil cannot be replaced, I will not waste my money. Some time down the road when I actually have the power to take advantage of an LSD I'll fork out he money for a HLSD.

PS. sorry for the thread jack.

 

Your best bet would be to keep your open diff case. Don't go with clutch types, go with a helical type. OBX sells good helicals for around $350, they last alot longer than the VLSD and clutch types. You just have to maintain the oil changes when your suppose to or else it will take a crap early.

 

The hicas on a 300, 240, and Skyline are all different. It sucks on a 300 and is always good to get rid of. It creates inconsitant suspension geometry and alignment and is the leading cause for wheel hop on launch. On a 240, its doesnt help really at all and weighs more. The car has a slightly quicker response at speed partially due to teh quicker ratio rack. On a skyline, its super hicas which is computer controlled and totally independant of the front wheels. It tends to feel a bit weird when it kicks in mid corner, but actually controlls the tail. The skyline is the only one where it could be seen as positive in performance driving, but its inconsistancy makes it a slight negative.

None of these are designed for parking like the old preludes. The are for maneuverablity at speed with very minor steering inputs form the rear.

For true performance they are best deleted. Ideal is a non hicas car with a hicas front rack like Bumnah suggested. This is what we have in the time attack car. If you have a hicas car, delete it, and either get an eliminator, or replace with non hicas rear suspension bits, subframe.

 

yes when i drove the skyline i didnt like it at all.. i had the dude pull the fuse for 4ws and it was a much better ride. i would delete it all

 

It defintely has an unsettling feeling at first, but you get used to it. With my r33 vspec, it had all kinds of electronics working together. This was particularly interesting when you hang the tal out on a corner, because it will let it go out, but then controlls it for you and slowly reels is back in. Not only that, but on hard low speed corners, it would actually encourage the rear to break loose a little to get the car to rotate.

 

In the KAZAMA HICAS eliminator it says professional installation recommended, does that mean there is welding involved or something

 

what the hell is hicas.

i'm not good with acronyms.

 

no, everything says that, lol. my coilovers said the same thing. you can do it yourself. friend of mine has a tt z32 with hicas. doesnt know anything about cars really and he was able to install the eliminator. and driftx, theres been like 5 thread on hicas in the past month.

 

i already ordered a kazama hicas eliminator. i want to disable the power steering in my car for better power at the rear wheels, would that be a big project?

also does HLSD help you hold a wider angle compared to a VLSD? i always thought HLSD would be better for reliability but wat about when you are trying to keep a wide angle drifting? thanks.

 

oh alright thank you for the info