Re: Torsen bites Performance Car

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

oh sh*t, i knew i shouldn't have said anything....

confused is as confused does...

my point was that scott says that the bite does happen in high cf conditions,
ie. a torque shift at t*max* at 7/10ths driving.  in low cf conditions, as you
have so accurately said, the locker can go from 0-100 torque and back to 100-0
torque.  depending upon grip.  in the same conditons, the torsen can go from
28/72 to 72/28.  so, by your own argument, the locker is worse!

my 70% torque with the torsen is in reference to one axle getting 0% torque
reaction (ie. its on ice).  i didn't state this, i thought that this would be
clear.

mmmm, which one of those is better?

dave
'95 rs2
'90 ur-q

>------------------------------
>
>Date: Wed, 22 Apr 1998 12:44:45 +0000
>From: Sargent Schutt <sargent@novagate.com>
>Subject: Re: Torsen bites Performance Car
>
>Dave Eaton wrote:
>
>>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.>
>
>Survey says? Bzzzzt. You are definitely confused: Torsen can bite on low cf
>all the more. That's what the magazine was commenting on. And if it can happen
>while going straight, it can happen in a corner, at which point the
>ramifications are a bit more serious. Torsen is doing its thing, true. But
>'its thing' is a nefarious force above 7/10's. Same physics apply in low as
>high cf, and b/c of the low cf it is even easier for the torsen to be
>activated, and per experience: fooled. This is true everywhere from gravel on
>a dry corner to ice. BTDT. If Scott ever implied torsen doesn't bite in low
>cf, my reading comprehension skills must be in decline...
>>
>>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%.
>
>Way off base there: Torsen can only shift 40% of the torque (in your 70/30,
>30/70 model: actually 22/78 = 56% max shift), not 70%. Again, you are
>confused. A locker effectively shifts from 50/50 to as much as 100/0 or 0/100
>(theoretically) as the F/R wheels gain/lose traction. Difference is the locker
>isn't a 'thinking' device, so it can't be fooled. The split is constant, only
>the road surface is 'unpredictable'. 
>
>Torsen hunts in a straight, and this is good for straightline acceleration.
>Torsen also hunts in a corner, and sometimes this is bad. Why? Because things
>like slip angle and wheelspeed differences at a given axle lead torsen to
>transfer torque in the wrong direction (fooling it). Moreover, it works so
>quickly as to be unpredicatable at times. Unlike the locker,  with the torsen,
>you might only be applyin of the torque to the tractive axle, as a result of
>the torsen having been fooled. Rare that it's that bad, but it can happen, and
>usually at the worst moment (above 7/10's). 
>