Zexel torsen, why am I one wheeling?
11-06-2013, 10:10 AM
#1
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Zexel torsen, why am I one wheeling? I've got a stock zexel torsen diff in my 2000 y87 firebird. With 3:42 gears. Also v8 swapped.
I cannot get the two wheels to lock when cornering. It will light up the inside tire but never locks. I changed the fluid to inspect it but I didn't see anything majorly wrong, but I've never done diff work. What can cause these to wear out without breaking pieces?
I cannot get the two wheels to lock when cornering. It will light up the inside tire but never locks. I changed the fluid to inspect it but I didn't see anything majorly wrong, but I've never done diff work. What can cause these to wear out without breaking pieces?
11-07-2013, 07:13 AM
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This is correct. They are finicky when turning hard right. A light right turn and mine would kick out though. Just the nature, or rather shortfall, of the design.
11-07-2013, 10:05 AM
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When I make a slight right and continue straight, the inside tire will light up and continue to spin. I can feel a shifting of weight like the left tire is trying to lock but it never does.
I use to spin both tires all the time at the same corner. Something is not the same
I use to spin both tires all the time at the same corner. Something is not the same
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11-07-2013, 01:33 PM
#8
IF you have a torsen and you've been hard on it in corners, you may have stripped some of the worm gears within the unit. A simple torsen test is to put the car on jack stands and see if when rotating 1 tire the other rotates in the opposite direction. This implies proper operation of the torsen. Feel for any unusual "roughness" when rotating like some odd resistance at some points during the rotation implying some teeth have been sheared.
The other possible breakage is the torsen worm gears relative to the case. As torque is applied in a uneven traction situation, the worm gears have a tendency to push outward on the casing of the carrier. This causes the unit to "crack" apart.
The other possible breakage is the torsen worm gears relative to the case. As torque is applied in a uneven traction situation, the worm gears have a tendency to push outward on the casing of the carrier. This causes the unit to "crack" apart.
11-07-2013, 01:52 PM
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Thank you, that's the info I need. I have always noticed the wheel spin opposite directions, but haven't tried now that I've been having problems. Nothing in the case looked broken and the gears looked good.
11-07-2013, 02:44 PM
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It's simpler than that. The stock Torsen has only
about a 2:1 max torque-biasing ratio limit. That
is less than the difference of static and sliding friction
for many materials-pairs. Let alone when you have
the right wheel lifting from axle torque reaction or
body roll in the corners.
So once you spin you get 3X spinning-tire torque to
the pavement - the spinner, and the stuck tire with
2X the torque.
Now if you did manage to break the second tire loose
(and assuming the two tires are identically loaded
and sticky) you would be down to 2X (1X apiece).
Meaning that one-wheel-peel is not necessarily
doing you any worse than a two track launch. And
I believe that the choice of a low torque-bias limit
was deliberate on GM's part - there are more capable
Torsen units, but spinning only one tire ensures that
there is still directional stability.
about a 2:1 max torque-biasing ratio limit. That
is less than the difference of static and sliding friction
for many materials-pairs. Let alone when you have
the right wheel lifting from axle torque reaction or
body roll in the corners.
So once you spin you get 3X spinning-tire torque to
the pavement - the spinner, and the stuck tire with
2X the torque.
Now if you did manage to break the second tire loose
(and assuming the two tires are identically loaded
and sticky) you would be down to 2X (1X apiece).
Meaning that one-wheel-peel is not necessarily
doing you any worse than a two track launch. And
I believe that the choice of a low torque-bias limit
was deliberate on GM's part - there are more capable
Torsen units, but spinning only one tire ensures that
there is still directional stability.
11-08-2013, 10:59 AM
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Right. In an open diff, you get torque only to the
fastest wheel (1X spinning). The Torsen will bias
up to 2X that wheel's torque over to the stuck
side, for a net 3X the acceleration you'd get with
an open (or busted Torsen) chunk.
Now spinning in air, back-torque is zero and you
get 2 times that countering the differential's
tendency to reverse the other against driveshaft
drag (i.e., nothing, so it acts like open until you
have some back-torque on one wheel and apply
the input through the pinion).
fastest wheel (1X spinning). The Torsen will bias
up to 2X that wheel's torque over to the stuck
side, for a net 3X the acceleration you'd get with
an open (or busted Torsen) chunk.
Now spinning in air, back-torque is zero and you
get 2 times that countering the differential's
tendency to reverse the other against driveshaft
drag (i.e., nothing, so it acts like open until you
have some back-torque on one wheel and apply
the input through the pinion).
11-10-2013, 03:33 PM
#13
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Torsens by nature, there will always be the risk that if one wheel goes light enough, it can easily lose traction and spin.
You'd need some sort of a plated diff if you want to prevent that sort of behaviour.
You'd need some sort of a plated diff if you want to prevent that sort of behaviour.
11-10-2013, 05:39 PM
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Interesting. I just never noticed it with the v6, it would always swing the back easily. Now with the v8, it shreds the inside until it shifts to second, then it will lock both and start swinging if I'm still spinning. It feels very awkward when they lock in second. Especially if I'm not expecting it.
