differentials are complex.... someone help

[madwilly240]

Okay, I'm reading all about differentials on howstuffworks.com.

They say that on an open differential... both wheels are delivered the same amount of torque all the time, but if you are offroading, and one of your wheels goes in the air, then you will get stuck, and that wheel will just spin and spin. I dont get this, because if both wheels are getting the same amount of torque, wouldn't the grounded wheel spin and get you out of there?

Also, what are the drag racing advantages to a LSD, what does viscous mean, what year 240's came with viscous, and am I the only idiot that doesnt get this?

[Dousan_PG]

OH YOUR A BIG IDIOT! DAMN FOOL!
haha

check this bud:

www.howstuffworks.com

http://auto.howstuffworks.com/differential.htm

you can read up on open diff and vlsds, lsds etc

start there, then ask more qs :)

read specifically

"Problems with Open Differentials"


what years with VLSD? 91 up. but dont believe the "if you have this and this then you have VLSD" that's nto true because someone can ALWAYS disprove it. iirc, the ONLY guarantee you have a VLSD is if you have HICAS!

[madwilly240]

dude.... im all over how stuff works.... thats why i posted. i dont get them cuz they contradict themselves. they say both wheels will always get same amount of torque.. and then they say that one wheel will just spin and spin if it gets caught up.

[240racer]

http://www.merkurencyclopedia.com/Trans,Diff/differential.html

http://www.houseofthud.com/differentials.htm

http://www.fizzindi.demon.co.uk/differential.htm

these are some of the better links I found when searching on Google for you.

[AKADriver]

Originally posted by dousan36
what years with VLSD? 91 up. but dont believe the "if you have this and this then you have VLSD" that's nto true because someone can ALWAYS disprove it. iirc, the ONLY guarantee you have a VLSD is if you have HICAS!

He has an S14, so no HICAS...

I suggest jacking up the rear of the car and inspecting the diff for the orange "VISCOUS L.S.D." sticker.

[MorganS13]

on a similar note.... i just got an S13 VLSD for $80 and an ABS driveshaft off the same car for $30 :D

[madwilly240]

what is a quaife?

and what kind of differentials do 240's have... are they just made by nissan i mean?

[AKADriver]

Quaife is a brand of helical limited slip differential.

Nissan differentials are made by Hitachi, IIRC.

[2FortyessX]

the way an open diff works is the second on wheel starts losing traction, all of the power is transfered to that wheel. so like if you were turning and flooring it then most likely only one tire would be spinning as you turned.

[burgy240]

Morgan...wher did you get it....in Columbus? if so do you think they have any for the s14? I'm in cleveland and I would def. be down there in a heart beat if so...;)

[Kaizen]

here, think of it like this. when you're making a u-turn while stepping on the accelerator, the outside tire has more distance to travel. so that means it would have to rotate a lot more than the inside tire. if even torque is applied to both tires then the outside one would slip right? well in order to solve this, an open diff gives the tire that's slipping more power, that way it can keep up with the inside tire.

now the problem with this is that in high speed cornering, centrifigual (sp?) force lifts the inside tire up. so an open diff sends most of the power to the lifted tire since it "senses" that it has less traction than the outside. in racing, this is bad, because all your power is getting wasted on a tire that doesn't have that much contact with the road. all the horsepower in the world doesn't mean **** if you can't put it down to the road.

an lsd gives power to both tires under acceleration. (and braking if you have a 1.5 or 2 way) but under light acceleration it acts like an open diff, so you can make low speed turns/ paralell park etc.

[Dousan_PG]

Originally posted by Kaizen
an lsd gives power to both tires under acceleration. (and braking if you have a 1.5 or 2 way) but under light acceleration it acts like an open diff, so you can make low speed turns/ paralell park etc.

do you mean VLSD? or true 1.5/2 way LSD?
becuase with a 1.5or 2 way you get equal power both on low speed turns. all the time (for 2 way that is)

1.5 is more forgiving as far as low speed/parallel park

a 2 way will give equal all the time and skip and hop and clunk and make all sorts of noises (depending on how tightly packed it is)

a VLSD is great for street. a 1.5 is more aggressive for street but still forgiving

a 2 way LSD is aggressive (maybe too much for most) for street.

[Kaizen]

oh... i thought that the 1.5 was more forgiving during braking while 2 way was full lock up under braking, while 1 way is only in effect while accelerating but i might be wrong.

[Dousan_PG]

no you are correct

1 way=lock during accelleration
1.5=lock during accelleration and sometimes braking
2=lock during accelleration and braking

as far as streetability, i'd go w/ a VLSD, 1 way or 1.5 way
2 way is a bit more 'hardcore' for street use. tires die faster and you get lots of weird noises from the diff depending on the brand and how many plates. people might flag you down in parking lots because your car sounds like its breaking. 2 way is alot 'ruder' to you

all depends on what you want to do with you car.

[Kaizen]

i agree with you there. 2 way is pretty damn harsh and if you drive your car on the street a lot you won't even be using it to its full effect. it also takes a lot of mastery on turn in to handle a 2way effectivley

[madwilly240]

okay now comes the purchasing questions.... it sounds to me like i'd wanna go with a one way... is that the same as VLSD?

also, where should i go shopping for these, and what are good brands to look for.

could i just put a old VLSD from a s13 in my 96? and would i need any other mods besides just the diff. and everything inside?

uhh, i think thats it for now. thanks a lot guys

[huntz0r]

No, 1/1.5/2-way LSD are clutch types, meaning that clutches (hence) lock together inside to keep both axles moving the same speed. VLSD has no solid parts that contact; it is a plate attached to each axle like this:
--||--
and in between those is a viscous fluid. When the plates start spinning different speeds the fluid creates resistance that brings them back in line. So it actually works more like a 2-way, just less effective and it takes a second to engage, unlike clutch type which engages almost immediately.

You can use the VLSD from an S13 but you have to swap the rear cover from your stock one onto it, because they mount differently. S13 bolts directly to the frame, S14 has bushings between the frame and carrier.

[drift into a curb]

VLSDs are 1.5 way from what I remember.

Archive topic on VLSD
http://www.zilvia.net/f/showthread.php?s=&threadid=21337

[kandyflip445]

On a side note....with an open diff, if you start to spin one tire that tire will spin at TWICE the rate as it normaly would. Say you were in 1st. Um....not sure how fast you can go at redline in first but i'm just gonna say 30....if the tire is slipin then it would be goin 60. Also if only one tire is going 60 and the other is stoped and then suddenly the spinning one gets grip this puts A LOT of strain on the driveline. (kinda like burnouts but a little worse...:D )

[240Stilo]

I got an open diff in my 240 and it was really noticeable how it worked once i took off my rims. The rear right tire was bald while the one on the left still had a pretty good amount of tread left....took a second to dawn on me what had occured......stupid open diff.

[adey]

Originally posted by huntz0r
No, 1/1.5/2-way LSD are clutch types, meaning that clutches (hence) lock together inside to keep both axles moving the same speed. VLSD has no solid parts that contact; it is a plate attached to each axle like this:
--||--
and in between those is a viscous fluid. When the plates start spinning different speeds the fluid creates resistance that brings them back in line. So it actually works more like a 2-way, just less effective and it takes a second to engage, unlike clutch type which engages almost immediately.
Not reeeallllyyy...

VLSD is 1.5 way, and the fluid doesn't just "bring them back in line" (all fluid is viscous, but different fluids have different levels viscosity; honey is very viscous, while ethanol is not very viscous.) The fluid heats up and expands no matter which direction the 'plates' spin, so it is in the strictest strictest sense (I think?) a 2-way, but it will never be as active on braking as it will on acceleration because the wheels aren't spinning nearly as fast (they're slowing down, and no power is being transfered to the plates/wheels either). Hence it's effectively (not technically) a 1.5-way.

I'm not 100% sure on why it's a 1.5 way vs. 2 way, but I think it's more along those lines than what others have outlined earlier.

[madwilly240]

thanks a lot guys, i guess ill be going with VLSD, since im not too big on drifting or rally racing. im more of a ... go to the drag strip once every couple months kinda guy.

[ChillyWilly3]

Maybe somebody already answered this for you, but just to answer your first question:

Yes, an open differential does apply the same torque to both wheels, but how much is applied given special circumstances is what HowStuffWroks.com is saying is the issue.

Open differentials apply only enough torque to keep a wheel from spinning. If you have a situation where one wheel is in the air while the other is still on the ground, the open differential will attempt to apply just the right amount of torque to the wheel that is in the air until it stops spinning. Unfortunately, the wheel will keep spinning because there's no friction (no opposing force to determine the proportional amount of torque to apply). Since it doesn't take much to spin a wheel in the air, the differential will apply little or virtually no torque to that wheel.

By definition, this same small amount of torque is applied to the wheel that is still on the ground. This applied torque is so small that it has little or no effect on the turning of that wheel (Hence, little or no movement on the wheel with good contact on the ground).

This applied torque will not change until the wheel in the air makes contact again on the ground. By then, the torque applied to both will be adjusted so that they both get the same amount of torque needed to overcome the ground (without slipping) and move your mighty 240SX proper once again.

I think this is right...Oh well...hope this helps.