Techniques To Practice for Track / Autocross

[lennon]

buncha street racers in this thread...

[nando]

The e30 is too cramped to literally heel-toe for me too and many ppl as well I'm sure..
I learned to use the ball of my foot to brake, and the outside rim of my foot to blip.

I think that's also what jlevie was trying to describe.

And I recently tried to learn the habit of double clutching instead of rev-matching with the clutch in now like I used to..

you can do it with a lot of practice but I usually don't literally "heel-toe" either (not that it matters much).

Now you want to try cramped/impossible, drive a late nissan sentra. the brake pedal is so high and touchy (to give girls confidence when they mash the brakes at the last second before they rearend somebody) you can't even reach the gas pedal no matter how hard you try. that's a car to learn double clutching in..

[gearheadE30]

I'm 6'4" and don't really have any issue with space for heel toe/double clutching. I've found that on the street using the balls of your foot works a lot better than truly heel-toeing, but on the track it's easier to modulate the brake and get the right amount of gas doing it with your heel. The bottom-hinged gas pedal makes it easy to do a large blip without a ton of heel movement.

[Jaxx_]

with autocross just worry about late apexing every single cone, and don't knock any down. get your braking right and you should be fine. If your motor has enough torque, don't even bother winding out 1st, just snatch 2nd and save yourself the trouble. On some courses, obviously it's not gonna work out so well, pivot cones, high speed sections will ruin this technique, but I've always found it to be a lot better than worry about changing gears every time you run out of revs in 1st.

[gearheadE30]

For what its worth, I even short-shift to second in the M42 unless the course start is basically straight.

[nando]

yeah, if I have a straight start I'll drag launch in 1st, but otherwise it's straight to 2nd and stay there for the entire course. It's rare that I need to downshift - maybe 2 courses out of dozzens I've attended.

[ed94r]

Autocross only advice:
Look ahead and have a plan for where you are going. This allows you to smoothly carry your momentum without having to jerk the wheel and upset the chassis. You *should be able to sit in grid and mentally run the course in your head prior to your run(s). A Course walk-thru shouldn't be taken as an opportunity to shoot the shit with your friends. You should use the time to memorize key places where you want (the car) to be, using key places on the course as reference points, such as key cones, pavement markings, and other elements (a tree, a trashcan, the edge of a building, etc). General advice: Walk it multiple times, Late apex to get "behind" a cone, slow-in fast-out is better than the opposite, and finally: rotation is your friend. A car that pushes will kill an autocross time. Don't make the car push by sudden "I'm lost!!!" movements.

There should be no advice to give for shifting on an autocross course. Without a drag-strip start, you will probably short shift to second and leave it there for an entire run 99% of the time. You should not be worried about (down)shifting...unless you drive an S2000.

Ed

[Bmil951]

^^^^ I like everything ed94r said, and can add something else: Read. Find yourself a copy of "The Physics of Racing" and read through it. I think you can find it on miata.net. It's priceless in your search for speed (it just so happens to be free too).

[TomSuddard]

Heel toe is great for the track, not as useful for AutoX because you usually don't downshift. At some AutoXs, I launch in 2nd, so I don't have to waste time on the 1-2 shift.

Put a (small!) piece of tape on your windshield so that it lines up with an object a hundred feet in front of you when you are sitting in the car. Don't look below it, and you'll learn to look ahead. Eventually, you won't have to rely on the tape anymore.

Left foot braking is a good thing to learn, even though I find it more useful on FWD than RWD. Essentially, you use it mid corner to help rotate the car. Don't do what most noobs do and take your foot off the gas when you left foot brake in a corner. That really upsets everything.

[87e30]

Alright guys, I'm a noob that's never been on an auto-x course. (I need to I know)

For a FWD car you typically brake hard to bite the front tires and turn in pretty hard right? With a RWD car you would still brake hard and bite the front tires, but come in slower and then modulate car position with the throttle? Whereas a FWD the throttle mostly just makes you understeer, right?

[619E30]

What is a double de-clutch?

[Bishop]

Can we please not turn this into a stupid-post-filled thread like 90% of the ones on R3V. I personally have benefited so far from this thread, and I'm hoping it gets stickied... So, READ, and contribute helpful comments, not stupid questions.

[gearheadE30]

87e30-this depends a ton on the car you are driving. The only fwd car I ever drove at an autox was a lightly modded Civic. Basically I tried to enter corners as quickly as possible because off throttle, it rotated fairly well and was easy to trail-brake. As soon as you get on throttle in most FWD cars, it will begin to understeer or spin the inside tire, and you lose all your rotation. Really, it comes down to practice and paying attention to what the car si telling you. They're all different, even if its the exact same car with a different set of tires.

619e30-double declutching is the same as double clutching as most of us car people know. The only time I've ever seen anyone double clutch an upshift was in a semi. Double clutching (or declutching) for us is as described by Ferdinand earlier in this thread.

[TomSuddard]

87e30, like gearhead says it depends entirely on the car and setup. The idea of lifting off the throttle and trail-braking is to play with the weight transfer. As a generalization, transfer weight to the front of the car (by braking or lifting), and you take weight off of the rear wheels, making it oversteer. Transfer weight to the rear of the car (by giving it throttle) and you get understeer.

But, throttle can do more than transfer weight. On a FWD car, throttle not only takes weight off of the front wheels, causing understeer, it can make them spin too, causing even more understeer. Tires can only do to much, and throttle can be the straw that broke the camel's back. Throttle can also cause oversteer in a RWD car. Even though it transfers weight to the rear of the car, theoretically causing understeer, too much of it can break the rear tires loose, causing oversteer.

Another generality: Most of the cars on here have been lowered substantially, and have much lower centers of gravity. Because of this, less weight will transfer compared to a stock car, and you'll find you have to be more aggressive with your inputs to get the car to do what you want it to.

[Ferdinand]

Another generality: You usually have to be more aggressive with a stiffer car and stickier tires. A stock car might not need very much to upset the chassis, as the soft suspension transfers weight very easily. Most of the cars on here have very stiff suspensions, so you'll probably have to use more braking and or throttle to get the weight transfer to happen.

One small, but vital, clarification required here. It is a common misconception that a soft suspension will transfer weight more easily than a stiff suspension, or because a car leans over further on its soft suspension that it is thereby transferring more weight than a stiff suspension that barely moves.

Weight is transferred because the car is experiencing an acceleration, whether that is seen as body roll from side-loading due to cornering, or pitching nose down due to braking, or squatting at the back due to acceleration.

The only thing that affects how much weight is transferred is the magnitude of the acceleration experienced and the ratio of CG height relative to trackwidth (for cornering) or CG height relative to wheelbase for accel/decel. At the same cornering speed a car that is low and wide will experience less side-to-side weight transfer than a car that is tall and narrow.

Given two identical cars, cornering at the same speed, the only difference being one has soft suspension and the other stiff suspension, they should each experience exactly the same amount of weight transferred from the inside wheels to the outside wheels. It is because that weight is being transferred that you can see the suspension moving. A soft car will lean further because soft springs compress more under that load. The stiff car will lean less because stiff springs don't compress as far under the exact same load increase.