86 5ktq in rally cross!

[Dan Cordon]

> 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