Finally LSD or Open

[kibbeyj]

I don't know what everbody thinks but I have read every single post on this subject. I get confused about the tires spinning on jack stands. Mine spins the opposite direction when in 1st gear (manual). I do burnout on assfault 2 marks. Grass 2 marks. Gravel 2 marks. Alot of people have said that if it spins the opposite direction it is open. My wifes derby car 89 caprice classic only spun 1 tire no matter what until we welded it posi. This lsd or open needs to get answered and stuck for sure to many ? about it. I know that the VLSD difs are ABS or Hicas or something. My car 92 240sx has no abs or hics. I think alot of people are just asking whether both tires will spin or just one they dont care about lsd or vlsd at least i dont. I am not a drifter and don't plan to be. Just curious about the lsds. Thanks for all your time.

[rsmithdrift]

Gawd........The sure fire way to know if your 240 came with an open diff or a VLSD is to look at the diff case. If there's an orange sticker, you have VLSD. If the diff's rear cover has fins on it, you have VLSD.

I have an open diff and I leave 2 marks most of the time. Unless I'm on uneven surface, or do a standing burn out (powerbrake) or try to cut a donut or turn in any way at all.

Even a VLSD will still spin them in the opposite direction if your car is in 1st gear when you try to spin the rear tires with them off the ground. You have to have the car in neutral, otherwise you'd be turning the motor if they both turned.

[kibbeyj]

Okay. Then in neutral with one tire off ground it does spin. So if I have an open which I am sure I do now. Tell me the difference between the 240 open dif and a chevy open dif. That is all I am saying. We need to figure out exactly how to tell people how to check. Lots of people saying do it in gear, in neutral, do burnouts and so forth. If in neautral is the only way to check then it needs to say that. To me the thing is posi because of the 2 marks on the road. I know it isn't but a chevy or other car with an open will only leave one. Why is this? Someone needs to do a pure writeup on all facts that are associated with an open, lsd, and vlsd. And why an open still can do 2 black marks at low and high rpm.

[rsmithdrift]

This is very long, but explains the physics behind open diffs and rear wheel drive.

The diffs are exactly the same. The difference is in the suspension and tire grip and wieght distribution and total vehicle wieght. A Chevy, Ford, or Dodge (just about any domestic) has a Live axle rear end. It's basically a straight rod cut in half with a diff in the middle. It's not independent.

So what happens is when you are accelerating the driveshaft will spin in one direction and will twist the live axle in the same direction, putting more load on the one tire. (torque steer anyone?? lol) With an open diff this means it will put more power to the other tire because it has less wieght being put on it which means it has less grip. Once it starts spinning one tire you get into a vicious circle of the tire loosing grip due to it spinning and spinning faster due to it's loosing grip and getting more power than the other wheel at an increasing rate because of it. However, if you have really shiity tires or are on ice, or gravel however it wont matter because neither tire has grip to begin with. That's why open diff cars can do donuts on gravel. Also wieght dist and total wieght matter for the same reason, pickups are a perfect example. No wieght over the rear tires = no traction at the rear end. Why do you think FF cars are so loose at corner entry and understeering from mid corner out?? It's all in the wieght distribution, they have heavy front ends and no weight over the rear end.

Nissans, and most imports, however, have a independent rear end. The diff is mounted solid to the chasis and the tire's are linked to it with a susp. set up similar to that of a FF car has in the front. Two spider gears per side which allow for the independence of the susp. Which, in turn, eliminates the torque twisting and means that the tire load depends on the way the car is sitting relative to the road and wether your turning or not (outside tire will always get more load) In a way it helps eliminate the need for an LSD. Though they are always better than open diffs. For example, get one wheel on wet pavement and the other on dry and see how many tire marks there are. Try to start up hill in a turn on very wet slick pavement and see how far you get, that's peg leg central lol.

[kibbeyj]

Okay that is all I wanted to know. Open dif is fine for me. I don't plan on doing burnouts and stuf with it tires cost too much $. I will run at drag track on some weekends but do not plan on going 200 mph in this car just a fun toy and show car eventually. Thanks for all the info guys. Maybe someone should sticky the response on this so other people will understand why the diffs are different. Thanks for all the info.

[Alfador]

I dont think it would really need to be stickied, people should know enough to search, especially since it has a nice descriptive title so it should pop up in the search grid easily.