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09:08:50 - 04/25/2024
Dakota Performance
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CasuObserver
Dodge Dakota
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8/15/2002
17:35:06
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 Subject: RE: about to buy. 4.10 open verse 3.92 lsd.
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At the risk of beating this dead horse, we need some clarification here on diffs & torque.
Correct me if I'm wrong, but in an open diff situation, you're always, under all conditions, always going to have the same amount of torque (not wheelspeed) equally distributed at the diff to the left and right axles. (Note that torque is not wheelspeed, or 'power'. Torque is twisting force.)
You can load up this torque [equally] on both wheels to the point that one of them breaks loose because the ground is more slippery on that side. At the point it breaks loose, that is the maximum amount of torque [ceiling] that can be applied to both wheels, and not more. So, on ice you can only build up a tiny amount of torque on the icepatch before you start to spin out. The exact same tiny amount of torque is also applied to the other wheel, but is usually not enough to do any good.
After the point that it breaks loose, if you give the motor even more gas and increase the power at the driveshaft, you'll still only have that same amount of tiny torque available to both wheels that the ice can hold, but no more. (In fact, you'll usually even reduce the the torque if you really spin the wheels, because it melts the ice a little bit, reducing friction). So, the extra power you apply through the driveshaft just accelerates the spinning wheel uselessly. The excess power is wasted by making the spinning-out wheel spin even faster.
TT, what CW is probably telling you is that the 4.10's will let you put more torque to both of the wheels. So much more torque, that you might be able to exceed the traction point where you'll be able to break one of them loose. Just like on ice, when one of 'em cuts loose & starts spinning, that's the ceiling on your torque to both wheels. Then, putting more power into the situation will just make that one wheel spin even faster.
Depending on your motor, the 4.10's will let you generate more wheel torque, more quickly, and get to the break-loose point more quickly. Then, when you're there, giving more gas will just waste more power in spinning one or both wheels. BUT BOTH TIRES WILL STILL BREAK LOOSE AT THE SAME TIME, IF THE TRACTION ON BOTH SIDES IS ABOUT THE SAME, and noo LSD or locker is going to have an effect on that.
However, at the exact point where one tire starts to break loose, you can *change* the normal distribution of torque (twisting force) from 50/50 to a little bit more, say 60/40 using LSD in favour of the slower wheel. So, the torque CEILING on the spinning stays the same, but the CEILING on the slower wheel is increased by about 15%, by the way the LSD works. (After that, though, more added power again still just gets wasted by 'dumping' it to the spinning wheel).
This 15% higher CEILING to the slow wheel(compared to what would normally be there with open diffs) is sometimes just enough to get a vehicle moving on ice. Same thing in racing. The torque *ceiling* for the good wheel is about 15% higher that the wheel starting to spin out. After that, again, any additional power just gets dumped to wheelspin on the slippery wheel. Because friction is usually pretty high on a dragstrip, if one side is a bit more than another, the extra 15% axle torque on the grippy side might be just enough to prevent a 'pegleg burnout'. -If you haven't reached the traction/torque ceiling yet though, or if both track sides have the same amount of traction, LSD won't help.
Now, with a locker, the *speed* of both wheels is constant. So, even though you may have reached a torque ceiling on the slippery side, you can still put more power into the situation, because ALL the excess will be put onto the good side (at least until it loses traction too). Not just 15% extra on top of the slippery ceiling.
Got it?
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conig
Dodge Dakota
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8/15/2002
19:44:40
| RE: about to buy. 4.10 open verse 3.92 lsd.
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actually with my locker it's 50/50 all the time unless turning and in most cases my locker does not let go.
I live in florida so we don't have snow but we do have wet slippery clay and if I stomp it I get two roaster tails now instead of one.
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TiredCasObser
Dodge Dakota
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8/15/2002
23:28:26
| RE: about to buy. 4.10 open verse 3.92 lsd.
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conig,
What 50/50 are you talking about, exactly?
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conig
Dodge Dakota
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8/16/2002
10:18:50
| RE: about to buy. 4.10 open verse 3.92 lsd.
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50 percent of power to each tire.
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