Re: Misquoting the spiderman (generation 1 spider bite)

[Dave Eaton <dave.eaton@minedu.govt.nz>]

err, no...in the low cf situation, the locker hunts from 100-0 and 0-100. 
thats a greater tshift than the torsen.  orin made this point (which i hadn't
appreciated), that, (eg. front axle on ice) due to the 0 torque *reaction* in
low cf in these conditions, the locker *can't* send torque to that axle
(because of the 0% torque reaction from the wheels on ice).  the result is 0%
torque to the axle, 100% (effectively) to the other.  spider bite.  although
this makes sense to me, i'm still not clear on this though.  is the panel still
paying attention?

either way, the locker either has a tshift max of 50% of torque, or 100% of
torque in low cf conditions.  thats a spider bite by your definition.  the
torsen is either better or worse, depending upon the paragraph above.  either
way, not a hill of beans.

in high cf conditions?  now thats a different story...

central to this is that a locker is not a torque distribution device, it is a
[driveshaft] rotation *equalising* device.  it will ensure that both shafts
rotate *at the same speed*.  if one shaft [wants to] speed up (no grip), the
other will [effectively] brake it, but the vast majority of the *torque* will
go to the axle with grip.  so torque will swing front to rear and back again,
while the dirveshafts are spinning *at the same speed*.  this is my
understanding of the physics of the locker.  panel?

nit 2:
when i said 70% torque, i was assuming there was 0% torque reaction from the
other axle.  net is 70%.

nit 3:
by the same definition, the locker also hunts (loses traction on one axle, 0%
torque reaction, regains traction and 50% torque reaction.  to use your own
words:
"A [locker] that "hunts" in a straight line will also hunt in a turn.  What's
the difference, the dumb switch is only more confused about the 'traction'
inputs in a turn, cuz there's more of em."

dave
'95 rs2
'90 ur-q

>Dave E. writes:
>>errr, no.  scott states that the torsen bite can affect a car when in high cf
>>conditions (dry tarmac), not low cf (snow, ice).  in the pc article, the
>torsen
>>is doing exactly what it is designed to do.  shifting torque at tmax (ie. 70%
>>of torque) on dry tarmac is what is called the spider bite.
>>i don't have any doubt that the locked centre could be better in low cf
>>conditions because the tshift is 50% of torque, while with the torsen, this
>can
>>be 70%.
>>dave
>>'95 rs2
>>'90 ur-q
>
>"Nit 1" :  
>Err,no Dave.  Scott states that the torsen bite occurs in a turn before wheel
>lift.  So that can be in high or low or anywhere in between.  As cf gets
>really low the spider bites sooner, altho one could argue that Trg is reduced
>(and that's true) the significance of that reduced Trg becomes higher.  IN
>other words, shifting smaller amounts of torque in low cf has a greater effect
>on the chassis dynamics in a turn.  Once the wheel lifts, a torsen is back to
>being a great traction device.  
>
>"Nit 2"
>A 22/78/78/22 can only SHIFT 56% of engine torque, not 70 Dave (Tshift Max =
>T1 - T2).  A locked center shifts no torque (again we assume same cf for 4
>tires for KISS), whereas a torsen can shift 56% of torque.  
>

>"Nit 3"
>A torsen that "hunts" in a straight line will also hunt in a turn.  What's the
>difference, the dumb switch is only more confused about the 'traction' inputs
>in a turn, cuz there's more of em.
>
>Your posts indicate that you are still confused of the torsen operation.
>Don't worry 'bout it though, the torsen is much more confused than you given
>the same inputs to traction.  
>
>
>:)
>
>Scott Justusson