Zexel Torsen Pros Inside, Explain Something Please!
11-18-2005, 12:13 AM
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Zexel Torsen Pros Inside, Explain Something Please! Here is the deal, my car will pull 2 wheel burn outs and spin both in a turn while the rear is still cold. But, once the rear warms up, only the inside tire will spin while turning. What is causing the bias to change when the rear is warm?
Also, what is there to wear out in these units? There are no clutches, only gears. I'm not exactly sure how the unit actually sends torque from input to one wheel or the other, maybe if I understood that better it would be easier for me to visualize exactly what is going on inside the differential.
One more thing, can someone explain to me how the slide gear works?
Thanks, Mike L.
Also, what is there to wear out in these units? There are no clutches, only gears. I'm not exactly sure how the unit actually sends torque from input to one wheel or the other, maybe if I understood that better it would be easier for me to visualize exactly what is going on inside the differential.
One more thing, can someone explain to me how the slide gear works?
Thanks, Mike L.
11-18-2005, 02:28 PM
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I've seen it said that thicker lube increases the
torque biasing limit.
The rough idea is, there are some helical gears
inside it that "climb" outward to the case as the
wheel torque differs. When they come into bind
then they send torque over to the other side.
The bind/stiction is what's going to vary with
diff fluid viscosity and lubricity. Viscosity goes
down with temp.
Other aspect is, your tires. The torque split max
is a little over 2:1 on the stocker (wear & fluid
effects aside). The difference between static
and sliding friction, as axle torque (this being
modified somewhat by things like axle lift reaction
etc.) will only be 2:1. So a tire that has a ratio
of static (sticking) / sliding (spinning) friction of
2:1 or less, will spin both at the limits while any
higher difference in traction will only spin the
first to break free, the biased torque can't put
enough to break loose the second.
Anyway, tire friction / traqction properties also
change a fair bit with heat and it's reasonable to
suspect that their ratio of sticking to sliding "mu"
may, as well. You know they get stickier when
hot, but maybe they also smear easier once
broken free (like warm butter). More mu-split,
no second stripe for you.
Heaviest, non-synthetic gear lube you can find
is worth a shot.
When you go to change it the first time I expect
you may see another reason - pile o' shavings.
That I think degrades the split capability, leaving
the gears with more climbing to do (and being a
sign that you've been overrunning the torque
split, often).
But I'm not a pro, just an enthusiast....
torque biasing limit.
The rough idea is, there are some helical gears
inside it that "climb" outward to the case as the
wheel torque differs. When they come into bind
then they send torque over to the other side.
The bind/stiction is what's going to vary with
diff fluid viscosity and lubricity. Viscosity goes
down with temp.
Other aspect is, your tires. The torque split max
is a little over 2:1 on the stocker (wear & fluid
effects aside). The difference between static
and sliding friction, as axle torque (this being
modified somewhat by things like axle lift reaction
etc.) will only be 2:1. So a tire that has a ratio
of static (sticking) / sliding (spinning) friction of
2:1 or less, will spin both at the limits while any
higher difference in traction will only spin the
first to break free, the biased torque can't put
enough to break loose the second.
Anyway, tire friction / traqction properties also
change a fair bit with heat and it's reasonable to
suspect that their ratio of sticking to sliding "mu"
may, as well. You know they get stickier when
hot, but maybe they also smear easier once
broken free (like warm butter). More mu-split,
no second stripe for you.
Heaviest, non-synthetic gear lube you can find
is worth a shot.
When you go to change it the first time I expect
you may see another reason - pile o' shavings.
That I think degrades the split capability, leaving
the gears with more climbing to do (and being a
sign that you've been overrunning the torque
split, often).
But I'm not a pro, just an enthusiast....
11-18-2005, 05:52 PM
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Man, you must have a master's degree in life! Something told me that you were going to be the one to answer my question. Every thread I read that addresses a problem, there you are. And your explanations are clear and straight forward. Thanks alot.
On a more serious note, I never thought about the difference between the static and kinetic friction of the tire. I am running fuzions right now and do notice that they bite fairly well until they break loose then it is VERY easy to keep them spinning. There could be a large difference in static and kinetic coefficients of friction.
Also, I will be changing the fluid soon and will post my opinions on the results.
On a more serious note, I never thought about the difference between the static and kinetic friction of the tire. I am running fuzions right now and do notice that they bite fairly well until they break loose then it is VERY easy to keep them spinning. There could be a large difference in static and kinetic coefficients of friction.
Also, I will be changing the fluid soon and will post my opinions on the results.
11-18-2005, 07:21 PM
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my torsen grabed the best after the dealer changed the oil to gm synthetic...its extremely thin.....also added 1 bottle of the gm friction modifier.With the standard heavy 80-90 weight gear oil it burned one wheel.After alot of trial and error i found that using 1 qtMobil 1 75-90 with 1 qtMobil 1 75-140 mixed equally with 1 bottle of gm friction modifier makes the torsen much quieter and it always works.
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11-18-2005, 07:57 PM
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Well, I really don't want to waste the money to change the fluid twice, so if anyone else has an opinion, or if anyone has result that support/conflict 99PontTA's, please speak up!
11-18-2005, 08:04 PM
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i can tell you what i heard and felt...with the thin gm synthetic it was very noisy but grabed great.With the M1 mix its much quieter and grabs good too.I'm afarid the thin gm synthetic may not ne good if you like to beat on it alot....if that the case i would use M1 75-140 with one bottle of the gm friction modifier...trust me on this i';ve tried alot of diff oils including redline royal etc.The M1 works excelant with the torsen.
11-18-2005, 08:24 PM
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my torsen was brand new...maybe yours is worn?I don't know,i'm just sharing what mine did.The price on M1 75-140 is gonna shock you...about 17 a qt...that why i mixed the M1 75-90 with it...it was only 8 a qt.
11-18-2005, 08:31 PM
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Yeah, I knew this stuff was a little pricey. Thats why I already said that I didn't want to have to waste the money to change the fluid twice. If it were $5.00/quart, I wouldn't worry about it.
11-18-2005, 08:54 PM
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Originally Posted by jimmyblue
I've seen it said that thicker lube increases the
torque biasing limit.
The rough idea is, there are some helical gears
inside it that "climb" outward to the case as the
wheel torque differs. When they come into bind
then they send torque over to the other side.
The bind/stiction is what's going to vary with
diff fluid viscosity and lubricity. Viscosity goes
down with temp.
torque biasing limit.
The rough idea is, there are some helical gears
inside it that "climb" outward to the case as the
wheel torque differs. When they come into bind
then they send torque over to the other side.
The bind/stiction is what's going to vary with
diff fluid viscosity and lubricity. Viscosity goes
down with temp.
You have only seen it said?
Is there any proven, direct relationship between fluid viscosity and bind/stiction.
99PontTA - Thanks for your input, it was very helpful. I will be going with the M1 mix and the additive. I will probably change it tommorrow and post the results after I burn a good $20 off my Tires.
11-19-2005, 03:53 AM
#16
i used some lucas stuff from advance auto...i forget the weight but it is the heaviest i saw there like 85/140 or something like that. Mine does posi at 5mph or 60mph.....it is also quiet...none of the "box of rocks" sound that i normally get from a torsen
11-25-2005, 06:13 PM
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Well, the results are in...
2 quarts of 90-140 conventional and some friction modifier to quieten it down, and WOW! What a difference. It is back to new; breaks both tires loose in turns now! Also, after getting the cover off I inspected the magnet; man was that thing clean! I wish I would have had my camera handy, but ohh well.
I want to thank everyone for helping me get this thing back to normal.
Mike L.
2 quarts of 90-140 conventional and some friction modifier to quieten it down, and WOW! What a difference. It is back to new; breaks both tires loose in turns now! Also, after getting the cover off I inspected the magnet; man was that thing clean! I wish I would have had my camera handy, but ohh well.
I want to thank everyone for helping me get this thing back to normal.
Mike L.
