Hey all, just wanted to share some observations from an autocross school day I participated in last weekend at Infineon Raceway (Sears Point).
The class was divided into 4 groups. There were 3 different “sections” of a course set up and we spent 45 mins driving a section, then moved on to the next section for 45 mins.
The first one I was doing was an oval, almost a skid pad and predictably the front pushed through it. So I talked with an instructor for awhile about it and he told me how to prevent it, or get out of it when it happens. I really didn’t understand it and it took several conversations before it began to make sense. It wasn’t until the afternoon session, when the 3 sections were attached to make a single course, that I figured out how to apply the technique he was talking about. I’ve also been reading the books that were recommended here (“Secrets of Solo Racing” by Henry A. Watts and “Winning Autocross Solo ll Competition” by Turner & Miles) and they’ve said the same thing, but it wasn’t until I could have a conversation with someone about it, and practiced it, that it made sense.

This will be remedial for most of you I’m sure, but on the off chance that someone else like me didn’t understand it, this is for you.
OH, and if any of you would like to expand on this discussion, please do. I’m still a beginner with this technique.

The Theory- So the pushing comes from the front end being un-weighted through a turn due to acceleration. You accelerate and the weight shifts to the back. The solution is to shift the weight of the car to the front. Either lift off the gas momentarily or step on the brake. Then immediately get back on the gas hard enough to slide/drift the back end around thereby steering through the corner with the throttle.

My solution- Lifting the throttle wasn’t enough to get the weight forward. And it just so happened that I wanted to practice Left foot braking so this seemed like a perfect opportunity. So as I went into a turn and the front end started to push, I left footed the brake (way too hard because I’ve got no practice with it), which clearly brought the weight of the car forward, then mashed the gas, which clearly brought the rear end around, and steered through the corner with the throttle/rear end. Success!!

This was amazing! And repeatable. And the pushing was preventable. By weighting the front end going INTO the turn, then getting on the gas, the pushing was preventable. There was a sweeper that needed left foot braking and throttle steering a few times during the turn but the pushing was significantly diminished/corrected and the time through the corner was much faster. With more practice, I may need fewer taps on the brakes through this type of turn.

These were low speed, autocross turns. I have no idea or experience with high speed track turns.

A note on Left foot braking – Apparently, when applying the brake and throttle at the same time, the engine cuts out. At first I thought I was loosing my supercharger, but when I released the brake all the way, while on the gas, the engine came back to life. Would be nice if we could disable this.

My car set up – Fresh Yokohama Advan AD08’s with 40psi up front and 37 in back, Stock sizes.
Eibach pro springs
TVT rear camber arms
Camber bolts up front
A small bit of negative camber up front and in back.

 

Amazing. But Stick shift guys do it by dropping gears. You can also do it by running the autostick in lower gears.

Each school of thought has their own model but IMHO,
Old school of course;
downshifting throws the weight forward, puts therear wheels a little loose and neverstops the steering wheels from rotation. Important in steering.
Old school;
Brakes are for stopping, not driving.

That said, the auto's don't respond with clutch feel, AKA feathering, so it is tricky to do it even with the auto stick.

Sounds like you had a lot of fun and learned some cool techniques. Be fun to test them on the Dragon.

roadster with a stick

the way it should be!

 

Very cool that you were able to do that class/event. It brought back great memories for me doing the Bondurant High Perf. course there many years ago. Learning trail braking seemed to be the hardest part for everyone. It is a delicate ballet of heel/toe coordination and it takes a lot of practice. I recall just when I was getting the hang of it we moved on to something else. I was unaware that we cut out when applying brake/throttle together in the X. I haven't gotten extreme enough with dinasrt to notice this; but you have me curious now. Let me know if you do this course again, it sounds like a real good time and experience. Bob

 

I've had some success trail braking but I'm not consistent. A few perfect corners followed by a few sloppy ones. The more weight you put on that outside front tire the more traction it will have but the less overall traction on the other tires so it's a question of how much is enough and how much is too much. Thats interesting about the harmonious brake and throttle ....... I've done it myself, gently, without trouble. Perhaps it cuts out on heavy applications?
I love driving schools. Lots of practice time without the pressure of a race. I've seen racers steer with the brakes, I think it will be a while before I can.

Les