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Discussion Starter #1
OK I already know this is a stupid question but how am I ever going to learn about my car if I don't ask?
What exactly is a LSD?

Let the flaming begin LOL.


OH I am now on my second tank of gas with acetone in it and I really notice a difference in both starting and running . also in the power and tech readings at different speeds. I only wish I had known about this almost two years ago when I bought my z in March of 04. Thanks for the answer to my stupid question guys I know a little about cars but as you can see a little is not enough.
 

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LSD= Limited Slip Differential

What this does is directs power equally to both the rear wheels. This helps traction from a stand still and going around corners. A normal differential, also referred to as an open diff, is set up to where power is directed to the rear wheel with the least amount of traction. What you get is when trying to spin the tires from a stand still is one tire spinning and the other one staying still. You've probably seen this in a lot of cars. When drag racing this can cause the car to go sideways off the line becuase only the one tire is spinning. With the LSD you get both wheels moving at the same time which hopefully decreases spinning and gets you moving off the line faster. For turns the open diff is set up to where the inside tire is moving faster than the outside tire. When taking a turn fast when the tires start to lose traction what will happen is all the power will be transfered to the wheel with less traction. This now causes the back end to break loose making for slower speeds around corners becuase you don't want to fish tail. With the LSD once the back end starts to loose traction both tires will have equal power making it easier to control and keeping better traction which means you can go faster around a turn. Someone can probably explain this better than me but basicly the LSD is much better for racing applications but I've heard it's a little more dangerous for daily driveing situations when it comes to rain, snow, ice, etc. I swapped in the 87-89 300zx LSD into my 280z and love it. Now I just need to get one for my 84 300zx.
 

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Dang good answer
 

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dang good answer?

most of it was incorrect.

"When drag racing this can cause the car to go sideways off the line becuase only the one tire is spinning."

thrust is equal at both wheels

"For turns the open diff is set up to where the inside tire is moving faster than the outside tire."

I have no idea where you could have possibly gotten this idea from.

"I've heard it's a little more dangerous for daily driveing situations when it comes to rain, snow, ice, etc"

whoever you heard this from should be beaten about the head and shoulders with blunt objects
 

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Having an open diff does make the car go sideways more than with an LSD. Besides seeing at with other cars it happened on my 280z and others on the S30 forum can confirm this. Yes thrust is equal at both wheels but if only one is spinning and the other isn't then the car whill begin to rotate where the back end goes to one side. As for the the fact where the inside and outside tires rotate at a different rate again from what I've read this is true. As for the issue about LSD's being more dangerous in slippery conditions I'm not sure but thought I would throw it out there so the original poster would know to look into that further. Rather than just saying I'm wrong why not correct me with what you believe the correct answers are. Yes it's possible to keep an open diff from going sideways when launching off the line but it's much easier to do with the LSD.
 

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Most of it was incorrect?
Most as in 3 sentences?

weird.
 

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Discussion Starter #8
NOw positrac I understand thanks guys.
 

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The outside wheel spins faster because it has a longer distance to travel in the same amount of time.

Speed = distance/time

But otherwise, solid info.
 

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OK. technically speaking i can't find anything wrong with 280zx/300zx's answer, but it may be a little misleading.

A standard open differential will always transfer the most power to the path of least resistance. So, if you are making a turn at ridiculous speeds, all the weight of your car will be transferred to the outter side of the car. Since in this case all of your weight is on the outside, that wheel will have much more grip than the inside wheel, and in this case your inner wheel is likely to start slipping as your differential transfers most of the torque to that wheel. Once that inner wheel has started slipping because the coefficient of static friction (the power needed to break the grip and start spinning) all of the sudden ALL available torque is sent to that wheel, because its the path of least resistence. now you start to slide out of control. this is usually considered BAD.

Now, when you have a limited slip differential, the differential employs some type of clutch to help reverse the symptoms described above. In this case, the most torque is transferred to the wheel with the most grip. So now when you're making that really fast corner, since all of the weight again is transferred to the outter side of the car, the limited slip differential will reverse the natural power distrobution sending most of the torque to the wheel with the most grip. This will lessen the chances of slipping, hence the name "limited slip".

Usually the best type of LSD are the viscous fluid ones. These work similarly to the torque converter in auto trannys. search on Google for an explanation of how they work to get a better understanding.

hope that helps somewhat.
 

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WOW, you guys only complicate the answer. Lets keep it simple.

OPEN DIFF. Car driven by only one wheel.

LSD. Car driven by 2 wheels.

There are benifits to both.

Clownsarus.. Youve already proved to be an idiot, why would anyone listen to you.
 

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lol. 88hybrid, you beat me 2 it. Clown... ur a dumbass. dont post if you don't know what your talking about.
 

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Don't forgot about a "locker" or "line locked" diff. But we don't need to complicate things even more. I've never seen one for a Z so I guess this is redundant.
 

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88hybrid wrote:
> WOW, you guys only complicate the answer. Lets keep it simple.
> OPEN DIFF. Car driven by only one wheel.
> LSD. Car driven by 2 wheels.
> There are benifits to both.

OMFG! You should know better than that. Now all the idiots will think that again. An open diff is NOT driven by only one wheel. It is still driven by both wheels. With an open diff, I can still leave two black marks on the street.

read more:
<http://auto.howstuffworks.com/differential.htm>

quote from the pages (since no one will read it all)
The open differential always applies the same amount of torque to each wheel. There are two factors that determine how much torque can be applied to the wheels: equipment and traction. In dry conditions, when there is plenty of traction, the amount of torque applied to the wheels is limited by the engine and gearing; in a low traction situation, such as when driving on ice, the amount of torque is limited to the greatest amount that will not cause a wheel to slip under those conditions. So, even though a car may be able to produce more torque, there needs to be enough traction to transmit that torque to the ground. If you give the car more gas after the wheels start to slip, the wheels will just spin faster.
 

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Welded diffs ?!?

Seeing as we're talking diff basics-

I hear some drift type dudes (& tight people) get their diffs 'welded'.
(open diff that has been welded 'shut')

I'm sure this cant be a good option but I would like to know the facts.

Anyone know anything about this... pros,cons?



Post Edited (Sep 21, 2:57pm)
 

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Has anyone ever seen My Cousin Vinny? In the movie, Marissa Tomei gives a speech about positraction. I haven't seen it in a while so I can't verify if what she said is correct, but if it is, she makes the explanation very clear. ****, even if what she says was bullshit it's one of the best movies anyway.
 
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