Re: Understanding

[Eric Renneisen <renneie@hlthsrc.com>]

>YES eric you are correct, my interpretation of awd system was 
>wrong.  IT is side to side only.  However, processing those signals 
>front to rear is not a rocket science exercise.  Nor one with a 
>hardware change.

Maybe not rocket science, but not trivial either. Instead of a one-
to-one comparison, the control unit would have to make decisions 
based upon three-to-one comparisons. Even more complex if you 
add in steering and throttle inputs. By no means impossible, but 
more sophisticated than the stuff Ingolstadt's programmers have 
done to date, I presume.

><< As I've said before, if your going to go that far, why not ditch 
>>the torsen all together?
>GREAT IDEA.  You finally got my point.

The real question is, why hasn't Audi ditched it? (I know, a question 
better asked of the coaches.) Have they not found your problem, or 
have they not found a better solution?
 
>Remember with slip angle, the rear tires CAN spin faster than the 
>fronts, in fact you can have them spinning and smoking, without 
>the DRIVESHAFT spinning faster than the front.  For that EDL 
>could work.  I don't think you grasp the slip angle issue.  This can 
>work even as a release system.

Whoa. How can the rear tires spin faster than the fronts yet the 
driveshaft not? Slip angle changes the amount of torque required to 
rotate the tires at a certain speed, but surely it doesn't change the 
laws of physics. The driveshafts are connected to the wheels. If the 
front wheel spins faster than the rear, the front driveshaft must spin 
faster as well. Tell me how slip angle changes that.

>I can use physics to show what CAN happen.

Your hypothesis.

>WHEN? Sure wish I could.

The goal of science: to understand the world enough to predict 
behavior and use this knowledge to our advantage.

>Can I make it happen in YOUR car.  Yup.

Are you REALLY so sure? There are lots of variables in your 
model. I'm not saying you can't -- I am saying that you are taking 
a leap of faith based upon an incomplete hypothesis. I'd be happy 
to let you try your hand at my 'racing-iron', and even happier to 
reveiw the results over a beer.

>Tshift happens, and it CAN affect chassis dynamics.  Does it?  I 
>argue yes, you and/or others argues no.

I don't argue either way. As a scientist, I base my opinion on fact 
alone. There aren't enough facts to prove you right or wrong. You 
(and others) report an event. I don't deny that it happened, your 
word is fact enough for me. Your explanation of the cause, on the 
other hand, is nothing more than an educated guess. My mind is 
still open to other possibilities. 

>Well it explains my event, in terms of chassis dynamics and actual 
>experience. Exactly what I'd expect actually based on the physics 
>and the numbers. Noneventers cant' explain my event at all.  I can 
>explain nonevents easily.

Just because I can't come up with another explanation, doesn't mean 
that yours wins by default. It's very easy to look at a hypothesis 
backwards and say "it works out so well that it HAS to be true!" 
It's a common mistake scientists make (myself included).

Eric Renneisen 
'90 CQ 20V  -  my 'racing-iron'  ;^)
Chattanooga, TN