LSD? - Page 2

mr2gq · 02-20-2008, 12:57 PM

Lol dude ur crazy. If a car leaves two mark is got lsd/posi. Just cause a car is balanced a certen way doesnt mean its going to put power to the other wheel and make it move and leave a black mark

fosley · 02-20-2008, 02:09 PM

If the weight on both tires is identical, the force exerted against each tire is identical, therefore there is no tire with less traction, therefore you get two black marks.

I've put two marks on the ground with several open diff cars. Do a few searches on this and other MR2 boards and you'll see I'm not the only one.

mr2gq · 02-20-2008, 02:22 PM

Dude the wheel has to have power going to it to put to black marks. That is why it leaves 2 black marks. Again force beng put on that tire does not make it move. THe tire will only move as fast as the car is moving unless power is put to it lol! This is about as funny as the last guy who said lsd is only good for doing donuts and smoking the tires but isnt good for take off lol

fosley · 02-20-2008, 03:06 PM

Umm, both wheels have power on an open diff. It's not 1-wheel drive. As long as you aren't spinning tires, there is absolutely no difference between an open diff and limited slip. If one wheel starts spinning and the other doesn't, an open diff will route extra power to the wheel that's spinning, and if you keep romping on the throttle you'll end up with the spinning tire having 99% of the power and the non-spinning tire having 1% of the power and you'll go nowhere. However, if both tires break loose at the same time and continue to have similar traction, you'll get two black marks (or two ruts if you're on sand).

And yes, force has a lot to do with it. The traction on the tire is determined by 3 things; how sticky the ground is, how sticky the tire is and how much force is smashing the two together. Less force equals less traction; hence why the inside tires spin first (under throttle) or lockup first (under braking). You can also use this to get both tires spinning on a car with open diff by shaking the wheel back and forth (well, it works on a couple front-wheel drive Hondas; not sure about RWD).

Edit: Ok, here's the easiest way to tell if a car has LSD: put the right side in sand and the left side on pavement (or vice versa) and drop the clutch. LSD should accelerate the car with the wheel on pavement while spinning the tire in the sand. Open diff should just spin the tire in the sand and go nowhere. In a car with really strong LSD or a solid axle/welded diff, the car would start moving and the tire in the sand wouldn't spin because it's moving at the same rate as the tire on the pavement (it would turn, just not spin and fling lots of sand everywhere).

Edit2: In the above test, make sure you have another car and a chain or rope, in case you don't have LSD and get stuck.

mr2gq · 02-20-2008, 03:34 PM

Ok did some more reading and I stand corrected lol learn something new everyday

jazzcornet · 02-20-2008, 05:54 PM

Quote:

Originally Posted by fosley

Umm, both wheels have power on an open diff. It's not 1-wheel drive. As long as you aren't spinning tires, there is absolutely no difference between an open diff and limited slip. If one wheel starts spinning and the other doesn't, an open diff will route extra power to the wheel that's spinning, and if you keep romping on the throttle you'll end up with the spinning tire having 99% of the power and the non-spinning tire having 1% of the power and you'll go nowhere. However, if both tires break loose at the same time and continue to have similar traction, you'll get two black marks (or two ruts if you're on sand).

And yes, force has a lot to do with it. The traction on the tire is determined by 3 things; how sticky the ground is, how sticky the tire is and how much force is smashing the two together. Less force equals less traction; hence why the inside tires spin first (under throttle) or lockup first (under braking). You can also use this to get both tires spinning on a car with open diff by shaking the wheel back and forth (well, it works on a couple front-wheel drive Hondas; not sure about RWD).

Edit: Ok, here's the easiest way to tell if a car has LSD: put the right side in sand and the left side on pavement (or vice versa) and drop the clutch. LSD should accelerate the car with the wheel on pavement while spinning the tire in the sand. Open diff should just spin the tire in the sand and go nowhere. In a car with really strong LSD or a solid axle/welded diff, the car would start moving and the tire in the sand wouldn't spin because it's moving at the same rate as the tire on the pavement (it would turn, just not spin and fling lots of sand everywhere).

Edit2: In the above test, make sure you have another car and a chain or rope, in case you don't have LSD and get stuck.

that's pretty funny!

Recklesss · 02-20-2008, 06:15 PM

most of my LSD equipped cars (mostly 240SXs and Corollas), if you lift the rear of the car and turn one wheel one way, the other wheel will spin the other

dunno if that only works on heavy duty diffs (i.e. two-way aftermarkets)

fosley · 02-21-2008, 09:43 AM

I believe that an open diff will spin the tire the opposite direction, while LSD will spin both tires the same direction. However, the stock MR2 parts use a viscous LSD, so at speeds you can acheive with your hand, it tends to act more like an open diff, since the viscous fluid requires quite a bit of pressure to apply any real force to the other side. Clutch-types and probably helical will spin both the same direction at by-hand speeds, as will a locked or welded diff. Also, I think if both wheels are spinning the same direction, it will make the driveshaft and/or output shaft spin, so you can't do it (with normal human strength) when the car is in gear.

Another indicator of LSD is when you go around tight corners and one wheel makes skidding noises; because one wheel normally turns faster than the other through a corner, if you make them spin at the same rate one has to skip to make up for the distance. It's not a sure-fire indicator though, because open diffs occasionally do that; my friend's '69 Mustang with 11½" rear tires skips like it has LSD, which we're assuming is the outside of each wide tire catching up to the inside of the tire. Edit: And the lack of skipping isn't sure-fire either, because weaker LSDs, like the stock MR2 ones, have enough give to let the car behave normally through low-throttle corners.

02-20-2008, 03:06 PM	#24 (permalink)
fosley Some Skills Join Date: Aug 2007 Location: Tucson, AZ Posts: 91 Thanks: 0 Thanked 7 Times in 7 Posts iTrader Rating: (1/100% )	Umm, both wheels have power on an open diff. It's not 1-wheel drive. As long as you aren't spinning tires, there is absolutely no difference between an open diff and limited slip. If one wheel starts spinning and the other doesn't, an open diff will route extra power to the wheel that's spinning, and if you keep romping on the throttle you'll end up with the spinning tire having 99% of the power and the non-spinning tire having 1% of the power and you'll go nowhere. However, if both tires break loose at the same time and continue to have similar traction, you'll get two black marks (or two ruts if you're on sand). And yes, force has a lot to do with it. The traction on the tire is determined by 3 things; how sticky the ground is, how sticky the tire is and how much force is smashing the two together. Less force equals less traction; hence why the inside tires spin first (under throttle) or lockup first (under braking). You can also use this to get both tires spinning on a car with open diff by shaking the wheel back and forth (well, it works on a couple front-wheel drive Hondas; not sure about RWD). Edit: Ok, here's the easiest way to tell if a car has LSD: put the right side in sand and the left side on pavement (or vice versa) and drop the clutch. LSD should accelerate the car with the wheel on pavement while spinning the tire in the sand. Open diff should just spin the tire in the sand and go nowhere. In a car with really strong LSD or a solid axle/welded diff, the car would start moving and the tire in the sand wouldn't spin because it's moving at the same rate as the tire on the pavement (it would turn, just not spin and fling lots of sand everywhere). Edit2: In the above test, make sure you have another car and a chain or rope, in case you don't have LSD and get stuck. Last edited by fosley; 02-20-2008 at 03:17 PM.

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02-20-2008, 12:57 PM	#21 (permalink)
mr2gq Banned Join Date: Nov 2007 Posts: 447 Thanks: 0 Thanked 2 Times in 2 Posts iTrader Rating: (1/100% )	Lol dude ur crazy. If a car leaves two mark is got lsd/posi. Just cause a car is balanced a certen way doesnt mean its going to put power to the other wheel and make it move and leave a black mark

02-20-2008, 02:09 PM	#22 (permalink)
fosley Some Skills Join Date: Aug 2007 Location: Tucson, AZ Posts: 91 Thanks: 0 Thanked 7 Times in 7 Posts iTrader Rating: (1/100% )	If the weight on both tires is identical, the force exerted against each tire is identical, therefore there is no tire with less traction, therefore you get two black marks. I've put two marks on the ground with several open diff cars. Do a few searches on this and other MR2 boards and you'll see I'm not the only one.

02-20-2008, 02:22 PM	#23 (permalink)
mr2gq Banned Join Date: Nov 2007 Posts: 447 Thanks: 0 Thanked 2 Times in 2 Posts iTrader Rating: (1/100% )	Dude the wheel has to have power going to it to put to black marks. That is why it leaves 2 black marks. Again force beng put on that tire does not make it move. THe tire will only move as fast as the car is moving unless power is put to it lol! This is about as funny as the last guy who said lsd is only good for doing donuts and smoking the tires but isnt good for take off lol

02-20-2008, 03:34 PM	#25 (permalink)
mr2gq Banned Join Date: Nov 2007 Posts: 447 Thanks: 0 Thanked 2 Times in 2 Posts iTrader Rating: (1/100% )	Ok did some more reading and I stand corrected lol learn something new everyday

02-20-2008, 06:15 PM	#27 (permalink)
Recklesss Ruler of Signatures Join Date: Jan 2008 Location: Oregon Posts: 359 Thanks: 6 Thanked 7 Times in 6 Posts iTrader Rating: (0/0% )	most of my LSD equipped cars (mostly 240SXs and Corollas), if you lift the rear of the car and turn one wheel one way, the other wheel will spin the other dunno if that only works on heavy duty diffs (i.e. two-way aftermarkets)

02-21-2008, 09:43 AM	#28 (permalink)
fosley Some Skills Join Date: Aug 2007 Location: Tucson, AZ Posts: 91 Thanks: 0 Thanked 7 Times in 7 Posts iTrader Rating: (1/100% )	I believe that an open diff will spin the tire the opposite direction, while LSD will spin both tires the same direction. However, the stock MR2 parts use a viscous LSD, so at speeds you can acheive with your hand, it tends to act more like an open diff, since the viscous fluid requires quite a bit of pressure to apply any real force to the other side. Clutch-types and probably helical will spin both the same direction at by-hand speeds, as will a locked or welded diff. Also, I think if both wheels are spinning the same direction, it will make the driveshaft and/or output shaft spin, so you can't do it (with normal human strength) when the car is in gear. Another indicator of LSD is when you go around tight corners and one wheel makes skidding noises; because one wheel normally turns faster than the other through a corner, if you make them spin at the same rate one has to skip to make up for the distance. It's not a sure-fire indicator though, because open diffs occasionally do that; my friend's '69 Mustang with 11½" rear tires skips like it has LSD, which we're assuming is the outside of each wide tire catching up to the inside of the tire. Edit: And the lack of skipping isn't sure-fire either, because weaker LSDs, like the stock MR2 ones, have enough give to let the car behave normally through low-throttle corners.