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Missing in action
Dave E writes:
>no, 100% to the spinning wheel (aka open centre wheel lift) and what happens
>the vehicle? loss of *all* drive. think about that.
No, a spinning wheel does not lose all of it's drive. It transmits torque,
just less of it. Trg to the ground reduces. So does every other diff with a
wheel lifted. More or less? Well, TIB than an open, good point. What about
> this means a big
>oversteering moment (like a total throttle lift), without any ability to
>correct with the throttle. this effect is much worse than the other
>in the locked centre, you have have a bigger tshift to the rear than you do
>with the torsen, with 100% of torque at the rear axle (with equal driveshaft
>rotational speeds). with the torsen, you have a tshift of 50% of torque to
>rear until 75% of torque (the bais ratio) is rearwards.
>wheel down (after wheel lift):
Arghhhh. You don't get it Dave. No question. No big deal. TIB than an
open, no question. Than a locker, be careful. How does a torsen get wheel
>in the locked centre 50% tshift occurs to the front.
>with the torsen, tshift to the front is 25%. less tshift, better
A locked center Tshifts nothing. Be careful of your lack of proper
>ok, so you're saying that the tyre does not impact cf. it does, of course,
>does the chassis loading on the tyre. so, ipso facto, the quality of the
>tryes, and more particularly, their behaviour at various slip angles are very
>important. doesn't the chassis have a fundamental affect of tyre load? you
>bet it does...
We could just as easily say your "given" choice of tire is wrong for the
chassis dynamics exercise given cf. I suppose you could change for the best
tire for every cf. Sounds a little unrealistic?
>?it all seems like chassis dynamics to me...
Point in time, advantage wider stickier tire. Damn it's raining. Now what?
Chassis dynamics. Oh yea, baby. How bout leaving the tires as a given, and
change cf? You make the exercise too complicated.
>you misunderstand what i'm saying.
>he coefficient of friction does *not*
>change over the wide range of slip angle as supported by most tyres.
>it's input to the "dumb" torsen is immaterial. certainly up to 70% on a dry
NO. You don't understand a torsen center making that statement. Stop and
understand the switch. You are wrapped up in a variable that has a point of
cf reference only. And unecessarily adding another variable to a dumb device,
and you don't need to know what the tire is. The torsen doesn't care, and the
slip angles don't either.
>scott, you have been telling us all that the torsen gets confused with slip
>angles, because it can't understand the difference between traction and slip.
>ok, i say, so what? for the tyres you and i use, the coefficient of friction
>provided by the tyre is the *same* over a wide range of slip angles.
>it *makes no difference* to the operation of the torsen. by definiton. no
>argument, at least to the point of the slip angle increasing to the point of
>*decreasing* cof. your argument (at least the 7/10ths on a dry road bit),
>*not* affect the torsen.
Slip angle and relative slip angle are variables to torsen output. cf is a
constant to all 4 wheels. You don't understand the torsen Dave. Tires aren't
the issue. A wide range of slip? What the heck does that mean. Where is
relative slip (which Stan admitted can also fool a torsen) in this whole very
>ref: carrol smiths book.
>btw, the torsen is capable of locking 75/25 to 25/75, not 22/78, 78/22 as you
I have documentation of both. Be careful. Maybe a question to ask Stan.
Irrelevent for the whole thread. 75/25 or 78/22 is oversteer, 25/75 or 22/78
is understeer. Bite happens.
Referencing carroll smiths book is fine and dandy, however you need to
understand torsen inputs to make the arguments above. You don't. Not a big
deal. But ditch the tire thing dave. A) It's confusing, B) it's not a
relevent input to the torsen, cuz it's too dumb, and C) it's not relevent to a
torsen at all except for a given cf. Cf is a constant, that doesn't make it a
given for the device. Change cf, your tire argument takes a dump. You want
to add tires into the equation. Great, then we need to collect data on what
is the BEST tire for every cf the chassis will encounter. Which tire would
that be exactly? This is tunnel vision in a real world. Darn turns.
Dave, you don't get how a torsen center works. And you own two of the finest
audis with them