Subject: Re: A grand opening in the Diffy-q's

[C1J1Miller@aol.com]

The explanations are still clear as mud.
Here's how I visualize it:
Gen 1 locker quattro.
All 4 wheels off the ground, center/rear unlocked.
First gear:  one front wheel spins (least resistance to spinning).  Engine 
producing couple HP max; add throttle, wheel spins faster, and engine races 
towards redline.  All the torque is applied through that one wheel; the 
torque to the other wheels is less than what is required to overcome 
friction, etc. and spin the wheel.  Open diffs allow torque to shift to the 
point of least resistance (least traction when driving).
Stop the engine, lock the center diff.
Now, one front and one rear wheel spin.  Available torque is split between 
the two 50/50%ish; if the handbrake is applied to the rear wheels, you'll 
stall the engine, if you hit the gas, max torque is shifted to the rear wheel 
and you'll burn up your brake pads.
Stop engine and lock both center and rear diff:  now one front and both rear 
spin.  The locked rear and the locked center function the same:  both must 
spin together as if they are a solid axle.

Now: torque is force applied.  Put said car on 4 rollers (a 4-wheel dyno, 
say).  Put no resistance on the rollers, and you'll have the same situation 
as when the car is in the air.  Now, say the car is still running in first, 
center diff locked, rear diff locked, so one front and both rear wheels are 
spinning.  Start braking the right rear wheel roller; applied torque on that 
side will increase and be _greater_ than on the free-wheeling left rear side 
(or front); engine will stall unless throttle (read: increased torque) is 
applied.  This is the same situation you'd have if you were on ice, with 
traction only at one rear wheel.  The three wheels should turn at the same 
speed; amount of torque applied in this case is limited to that which can be 
put down by the rear wheel, meaning there is near 0 torque (only enough to 
overcome friction and rotational acceleration) to the other 2 turning wheels 
and the stationary front wheel, and max torque to the wheel with traction.  
What does this mean?  you can get 0% front, 100% rear; then 100% front, 0% 
rear, if you lose traction (say hit a patch of ice).

chris miller, windham nh, c1j1miller@aol.com