86 5ktq in rally cross!

[Cody]

I've never had the pleasure of driving my Quattros in any weather below 50 degrees F, so I don't really know about snow and ice, but I have no problem getting my car to rotate nicely with all diffs locked on wet pavement. Even on dry pavement it's stepped the back end out of line more then once in certain situations. I bet though that the more then stock ammount of power on my car is the culprit here. 

Heres a bit of wisdom from the Champion camp that they applied to thier S4s and RS6s. They have the torque split biased rear, about 60% of the power is biased to the rear, but that doesn't apply here since we can't do that. But what does apply is the driving style. The only way to make them go fast (talking to Mr. Stuck who has a house down the street from me showed that this same technique was required on the Trans Am and IMSA cars) was to purposely get the car unsettled right at the end of the braking zone and then apply the power and let the rear end break loose. Once the rear is loose you can very easily guide the car through the corner with the power on. Basically you just rotate the car arround the apex then mash the throttle. With the car in a very subtle drift you can use the driving force of the front wheels (weather they have traction or not they are still pulling the car wherever they are pointed) to pull the front end towardns the inside of the corner and with th!
e rear loose it should swing right to where you want it. Once you're pointed where you need to be pointed just straighten the wheel and the car should pretty much track right out of the corner and regain traction quickly. Basically its rally technique, but I'm not talking about a fully crossed up drift, this is just a very very sublte controlled slide. Ever driven a jet ski? They use the thrust to steer so if you aren't on the throttle they dont steer - no rudder, you must use the throttle if you want to turn. Think that way with your Q car, IME it will _not_ turn without proper throttle application.

Talking of your diff lock situation my vote says use a solenoid stolen from an old starter and a button on the back of the steering wheel for momentary diff lock use. You get yourself in the corner, hit the button to leave the corner and let go once you're up to speed and no longer need the lock.

-Cody Forbes
No longer with Black Forest Racing - I'll post later more detail on this
http://www.500tq.com
'86 5ktq
'87 5ktq EFI/K27 - Drift machine w/ diff locks on!
'88 80 4cyl
'88 90 4cyl

---------- Original Message ----------------------------------
From: Dan Cordon <cord4530 at uidaho.edu>
Date: Tue, 10 Feb 2004 13:02:00 -0800

>> On snow and ice, you SHOULD be able to get the car to rotate, so I'd keep
>> the diffs locked.
>
>Actually, I've done quite a bit of *ice auto crossing* this winter 
>during each of the big snow dumps we've had here. There's a particular 
>parking lot that's great for oval racing (alone, that is). I've been 
>trying to learn more how the car responds with each of the diffs locked. 
>I'd run about 20 laps open, 20 with center locked, and 20 with both 
>locked, then repeat in the opposite direction.
>
>That said, with both diffs locked the car really wants to go straight. 
>Getting the initial turn in is difficult at best. However, once the turn 
>is initiated, I felt like having both diffs locked made it easier to 
>control the drift.
>
>Even having just the center locked made the initial turn in slightly 
>harder, but nothing compared to having the rear locked.
>
>I would consider putting a switch on the throttle if possible. Something 
>where any more than ~50-70% throttle would engage the vacuum locks. When 
>you go below that, it would disengage. This way when you're giving it 
>throttle as you exit the corner you'd get the locked diff traction, but 
>off the throttle entering a corner you'd be fully open.
>
>Not having thought much about this, I'm not sure on the details of where 
>you'd want to mount such a switch.
>
>FYI, this was in my 87 5k that I was playing around with. Good luck with 
>the races!
>
>-- 
>Dan Cordon
>Mechanical Engineer
>University of Idaho - Engine Research Facility
>
>
>
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