[torsen] Snow Driving

QSHIPQ at aol.com QSHIPQ at aol.com
Thu Dec 5 10:50:50 EST 2002


Ok, I'll chime in here.  For any specifics of lockers, please read my yearly 
Steamboat reports.  Scott, specific to your post, comments inserted.

In a message dated 12/4/02 2:47:41 PM Central Standard Time, 
quattro-request at audifans.com writes:


>having driven both types of quattros (non torsen and torsen), I must
>say that I do enjoy the torsen type of the 200q, despite not having
>the ability to lock the rear diff at over 15 mph.

Try interrupting the blue white wire that goes to the controller under the 
seat.  The 15mph lockout can be modified.

>On my 5ktq, I could spin the tires in rain before the center diff
>would control it, either that or the speed. I would go through front
>tires pretty quickly, nearly the same as my 5kt 5speed.

Unlocked I presume?  Since locked this wouldn't hold true.  That must be 
either one heck of a 1.8 bar mod, or crappy tires.  

> BTW- I run
>1.8 bar. Also, the 5ktq would't track straight on hard, wet launches
>or over wet painted roadway stripes. I'd have to lock the center,
>losing abs. I have locked up all fours doing this, too. Was able to
>kick the rear of the car out regularly :)

A locker without ABS isn't such a bad thing.  As Bob pointed out, ABS only 
gives you the ability to steer impending lockup.  A locked center diff 
however, gives you ideal brake force distribution, which, if you know how to 
threshold brake, can be infinitely better in terms of braking than ABS.  In 
the scenario above, the torsen and the locked diff would behave identically.

>On my 200, I feel this system is superior. Very hard to kick the rear
>out. More balanced tire wear. Car lauches straight, all the time.

Actually, the rear comes out easier on a torsen car than on a locker or open 
diff car, it's the nature of the device.  Turning radius makes the torque 
shift rear on a torsen car.

>Can't really spin a tire. 

That's because Trg goes down when you do.  Some consider this a good thing. I 
don't

>Next, even without locking the rear diff,
>its pretty tough to spin a tire. 

The torsen works the same with or without locking the rear diff.  

>I enjoy how automatic the system is;
>I retain the abs in bad conditions. 

Well, the system isn't "automatice" it's a LSD device.   It's passive.

>On highways, panic manouvers, I
>have more control under power, evidenced by my 85 mph swerve around a
>wrecked police car on I 80 in Pennsylavnia this past Sunday. 

You *don't* have more control under power, you have less, by definition.  The 
torsen hunts during any turn, since it can't accomodate slip.  Which means 
that as you were swerving under power (I won't comment on the circumstance), 
the torque allocation was shifting, it appeared to work for you this time.  
Counting on that could prove disappointing.

>I like
>that I can just relax and drive. IMO, this system feels like it's
>doing more than the type that preceeded it. 

It is doing more, the debate is whether that's a good thing or not.

>I like that hard 1.8 bar
>launches don't produce wheelspin, just forward motion in a straight
>line.

If you are doing a hard launch, you could lock the diff, in a straight line, 
there is no difference in torque allocation between a locker and a torsen.  
I'm intrigued by the definition of a "hard launch",  I have 2 10vt lockers 
running 22psi, my comment:  That's one *hard* launch.

>On power turns are great because the car goes where it's
>pointed at high boost levels. 

It can't by definition.  As you turn a torsen car, torque allocation goes to 
the rear, if that torque allocation rear, causes the rear tires to lose 
traction, torque allocation goes to the front 56% of it.  IME, that isn't the 
definition of "going where it's pointed", it just can't without some other 
sort of corrective action.

>I managed the spin my 5ktq around oing
>the same thing.

Drivers school?

>To avoid a war, this is based on my driving habits only. I like the
>torsen equipped cars.

I'd only suggest you understand what the device is capable of, and what it's 
not.  Right now, you are assuming a lot of things that the device, by 
definition, isn't capable of.  Which means that someday, based on your 
driving habits, the device is going to let you down.

>Next, it's a bad idea to use simultaneous braking and throttle on a
>torsen vehicle because the power will be distributed to the axle with
>the most braking.

Scott, if you look at any of the offroad sites, you can see contradiction to 
this statement abounds.  In fact, the MOST effective way to control a torsen 
is to apply braking while on throttle.  This reduces the torque shift antics, 
especially in high torque/cf ratio environments.  I wouldn't at all agree 
with the above statement, in fact, the exact opposite is true.  Power is 
distributed to the slower rotating driveshaft, period.  ANYTHING that causes 
that to be true will recieve the most torque.

I'm not with you on this post Scott.  The torsen cars *can* illicit good 
behavior when properly used and understood.  That said, a properly used 
locker in low cf environments would be difficult to best with a torsen AND 
abs.  Any winter driving school (high torque/low cf ratio) will reinforce 
that.

HTH

Scott "torsenboy" Justusson
lockers aplenty
87 type 44tqw 22psi lockers
'84 RS2URQ project lockers
'83 Urq electro pneumatic locker conversion
'86 type 44tq lockers
'87 4runner turbo lockers





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