Autocross Techniques

[shotgunslade]

I'm thinking about taking an autocross course and was wondering about driving techniques that work in an SVX The car is a heavy understeerer and being all wheel drive doesn't offer the opportunity for power-on oversteer coming out of corners. During the last few track days that I did, I was testing out trail braking as a strategy for getting the car to rotate in very tight corners. The strategy requires a delicate foot, because you have to move from limit braking while you are still going in a straight line to lesser braking when you turn in. If you continue limit braking at turn-in, the front tires break loose and you don't turn at all. I remember one very tight corner on the Pocono double infield course, where I could get the rear to come around quite a bit using this technique, allowing me to get on the accelerator sooner with very little cornering left to do, and thus little power-on uindersteer coming out of the corner.

Does this technique work in autocross? What other techniques have you found effective for getting our buggy to dance from cone to cone?

[LetItSnow]

What do you have for a suspension setup?

[svxcess]

Originally Posted by LetItSnow

What do you have for a suspension setup?

Besides what is in his signature, what else is left? Alignment settings? Spring rates?

245/40-17 Bridgestone RE01-R tires
Koni inserts with Ground Control coilovers
Eibach springs
K-Mac camber/caster adjustable strut mounts;
Urethane swaybar bushings
Bontrager22rear sway bar
Urethane differential bushing
Custom Whiteline adjustable rear lateral links

.

[LetItSnow]

I've got signatures turned off; they're mostly heavy filler.

Yes, what spring rates? That sounds a lot like what my Pearly had at one point.

[shotgunslade]

I have Ground Control Coilovers, lowered about 3/4 in fr and r, Eibach springs 345 lb/in fr. 285 lb/in r, Koni shocks, solid camber control top-mounts, new OEM control arms, camber bolts on the rear, Whiteline adjustable rear lateral links, urethane swaybar bushings, Brontrager rear sway bar, OT's 5 minute and 15 minute mods. I'm running 1.75 deg. negative camber front and rear, 0 toe front and rear.

[radarwhiz]

To respond to the original question: technique (and I do believe driver technique and skill is much more important than car modifications)

You are correct about terrible understeer on exit. Trail braking does alleviate much of that if you can brake later and rotate the car with the brakes even as late as mid-corner and aim for a VERY late apex in order to return to throttle sooner. That's for longer corners.

For the other most common feature of an autocross course, the slalom, what I've learned from one of the best I've ever seen in awd is to figure out an on-off rhythm with the throttle that matches your steering input. The technique here being to use throttle-lift oversteer to rotate around each cone, then back on throttle to catch and balance the car until the next cone. The throttle input here can be quite aggressive instead of the smooth modulation we're always taught and the car is actually a bit more 'tossable' than you might imagine.

Other than that learning to read the course and maintaining proper vision are the most challenging things. The idea is to find every place you can on the course to increase the radius of the turns and open up space to be on the throttle more of the time.

These are a few of the things I've learned, and I am very much a novice at this still

And most of all, have fun with it.

[shotgunslade]

Thank you, Radarwhiz, very informative. Did you ever use left foot braking. I took a 3-day rally school a few years ago, and left foot braking was the order of the day. The sequence was:
* turn-in (nothing happens on wet gravel)
* throttle lift, moderate braking (weight transfer, front tires bite, turn initiates)
* continue moderate braking through turn, maybe induce the rear to come around a bit
* lift off brakes, go immediately to throttle (turning straightens out)

Left foot braking allows instantaneous transition from throttle to brakes and back. Works well on dirt and wet gravel when you get the hang of it.

Wonder if it would work in Autocross

[radarwhiz]

I have not tried left foot braking yet. I just have not developed enough feel and control to be able to use it for braking yet. I see a lot of people who do very successfully especially since there is really no shifting to do.

[benebob]

SGS,
Never had much success with the SVX and left foot braking myself as I could never find the right feel for it. I think a lot of that was due to the SVX liking to lock itself up before it would break. Used to do it all the time in my XT6 autoxing as I needed all the help I could get autoxing it. Now that I got a new racing project car hope to get back into it myself, mostly track days.