"Frank Grimes" (FrankGrimes)
12/29/2014 at 23:27 • Filed to: None
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"Frank Grimes" (FrankGrimes)
12/29/2014 at 23:27 • Filed to: None | 8
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Wizards and gears and magicks thats how.
EL_ULY
> Frank Grimes
12/29/2014 at 23:30 |
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Neato! I don't feel any of it in my clumsy wagon lol. I think it way be broken :] C5 avant quattro, i think all 3 diffs are torsen.
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Frank Grimes
> EL_ULY
12/29/2014 at 23:34 |
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maybe cuz its instantaneous?
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EL_ULY
> Frank Grimes
12/29/2014 at 23:41 |
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One side of my car would spin on a wet turn very often. It does that a lot and the other side will never really catch. Also, sometimes just the front or just the rear will spin unless i really give it throttle then both front and rear will spin together. ... but not at first. During that front and rear engagedment, the left and right are never truly equal unless the throttle input is really high.
Torque vectoring was before my time. It is such a rad thing and hella useful im sure
HammerheadFistpunch
> Frank Grimes
12/29/2014 at 23:48 |
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moar detail here . This video, like most on the subject, gloss over the actual reason there is a limited slip locking effect.
Delusion77
> Frank Grimes
12/30/2014 at 00:32 |
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Neato
gogmorgo - rowing gears in a Grand Cherokee
> EL_ULY
12/30/2014 at 01:39 |
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The Torsen isn't absolutely perfect, no. The video is also slightly misleading. The helical gears only mostly can't drive each other... it's not a perfect lock. Because the gear teeth are angled and not straight, there's a certain amount of slip allowed. Also, unlike a locker or even a limited-slip diff, it isn't triggered by differentiating axle speeds, but rather differentiating resistance.
When in an uneven traction situation, you've got one wheel with low traction and a low resistance to spinning, and the other wheel has high traction and a high resistance to spinning. The low-traction wheel does still have some resistance to spinning, and even with an open differential could be moving the vehicle at least a bit. A Torsen diff has a torque biasing ratio, TBR, for example X : 1, which means that your high-traction wheel will push X times as hard as the low-traction wheel.
This means that the effect is greatly lessened with severely reduced traction on that one spinning side... as the maximum torque you're putting down with the faster-spinning wheel approaches zero, the maximum torque you can put down with the higher-traction wheel approaches X times zero – which is still effectively zero. Those in HMMWV's equipped with Torsens learned quickly that if you had a wheel off the ground, your magic diff became magically open and useless... but if you braked lightly, it put some resistance on the wheel, and magically you could get torque to the high-traction wheel.
Over time as the diff wears, the TBR gets reduced. Part of the diff's magics come from the gears interacting, and part of it comes from the element gears (blue in the video) thrusting the side gears (orange) against the sides of the case and/or each other and/or the washers in between the above. (I've torn down and rebuilt a Torsen a few times...) So like a traditional LSD's "clutches", they do have a limited life as the various friction surfaces wear down. I understand it's a longer life than a typical LSD has, but once it's worn down, you need new gears in the Torsen, not just clutch discs.
TxBrumski
> Frank Grimes
12/30/2014 at 11:18 |
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Aaaand there goes the rest of my day. The Learn Engineering channel is fascinating.
Captain_Spadaro
> Frank Grimes
12/30/2014 at 15:52 |
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Spacegrass
> Frank Grimes
01/06/2015 at 21:18 |
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I have an Aussie Locker in my current truck . I had a Torsen in my Ranger FX4 L2. Both have their advantages and disadvantages. The Torsen is most definitely smarter (and way friendlier in an urban environment), where as the Aussie is way more at home off the beaten path. It'll lock up, regardless of conditions. The Torsen doesn't work with a wheel off the ground/extremely low traction.
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Frank Grimes
> Spacegrass
01/08/2015 at 13:42 |
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I think I need to test mine out more to tell when its working. The other morning with my right rear wheel on ice and left on bare asphalt it was spinning and it seemed like the other side didnt want to do much of anything. of course this was in first gear. It seemed like it moved better once into 2nd.
Maybe it was working and both were slipping but I need to understand the limitations of it better.