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Performance Driving Tips |
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Home | Membership | Our Staff | Event Details | Classifieds | Links | Past Events | Goodies Store | Calendar |
Performance driving articles by Dale Willis, Vice President of PCA AZ Region, a frequent contributor to Going Places, and an avid driving enthusiast.
| Learn to Walk the Walk | |
| Make Haste Slowly | |
| Intro to "Heel and Toe" | |
By Dale Willis
You, like most participants, probably walk the course prior to an autocross. But are you getting the most out of it? Since every autocross site is different the obvious reason to walk the layout is to understand how the cones are set up, learn when and where to turn, recognize gates and slaloms and get a general feel for the course. Different course designers use the cones in different ways: Some set “pointer” cones to indicate which side of the cone or gate to drive. Some use a lot of cones to delineate the route while others are minimalists and set a few “gates,” i.e., pairs of cones that you must drive between. Study the course map if available to get an overall picture and pay close attention to each speaker at the drivers meeting.
As you walk, one of the most important things to note are transition points where you may become easily confused, like coming out of a turn and having to find a relatively distant gate. When one is new to autocross it is disconcerting to roll out of a turn and see a “sea” of cones ahead with no clue where to go. One of the things I like to do at transition points during the walk around is to squat down and get my eye level about where it is when I’m actually driving (okay it’s not much of a squat for me, wiseguys). It is sometimes surprising to see the different perspective you get at a driver’s-eye level.
A second and very important point is to not decide whether you “like” or “dislike” the course during the walk around. Each course is different and makes you hone different skills. Look at it as a challenge to overcome and don’t start with a negative mindset. Sure your 400hp turbo may not perform well on a tight course, but you’ll get a chance to eat those 914’s at higher speed events.
See how much you can lower your lap times during the day by adapting to the layout. And make the best of it – we’re all in this for the fun!
Okay, back to the track. Note the radius of the turns and whether any are “decreasing radius” turns which can be particularly challenging on a tight course. Note your turn-in point and where the apex of the turn might be. Walk with an experienced driver and listen to their comments and ask questions – we’re all willing to help you. Note points where the elevation changes and the car might become unsettled. Look for rough pavement or loose gravel that might make a segment slippery. Even though we sweep, it will build up under use. In fact, sometimes the best line isn’t the best line due to a buildup of rubber “marbles” or accumulated gravel during the day.
If there is a “slalom” (a single row of widely spaced cones around which you must alternately turn), determine which side of the first cone you want to pass for a quick exit from the preceding segment. Generally, you want to base that decision on the very last slalom cone. You want to be on the side of the last cone that sets you up for the best entry into the next turn. Pace the distance between the cones or at least note whether they are equal, increasing or decreasing in spacing. Because our sites are sometimes small, a designer may use ever more closely spaced slalom cones to slow you down prior to a change of direction. Occasionally a designer will designate on which side of a cone you must pass with a pointer cone. When driving a slalom segment you want to be smooth and develop a rhythm while staying close to the cones. Going too fast and swinging wider arcs just eats up time!
Now, once the session begins, keep in mind that “smooth” equals “fast” in an autocross. Even if you are smooth, a tight course with lots of turns doesn’t always feel smooth. And a driving style that feels fast to the seat of the pants, slipping and sliding, is not normally the fastest. A driver with the proper setup for the course, who follows the best, most efficient line while driving as smoothly as possible will log a top time. Watch a “hot shoe” for an example of smoothness combined with a good line. Ross Bentley in his book Speed Secrets says, “The slower you move, the faster the car moves.” Sounds a little like “make haste slowly!”
One of the most difficult things to do facing a sea of cones is to look ahead at where you want to go rather than where you are. It is particularly difficult when you are just looking for the next directional cone. Do what you can before the start and during the day to learn the course so you can look ahead to where you want to be. It is not as easy as on a road course and I don’t do it as well as I would like. While on the course watch the starter and keep driving laps until you see the checkered flag. Sometimes, due to a glitch in the timing system, we’ll give you an extra lap or two. Remember, too, to carry the throttle to the timing lights. Once the nose of the car breaks the beam you can brake smoothly to make the turnoff safely.
Now, once you’ve successfully learned to “walk the walk” you will then be able to “talk the talk” over a cold one at our traditional post-race session at a local pub. See you there!
By Dale Willis
One of my favorite driving instructors, Caesar Augustus (Roman Emperor, 63 B.C.-A.D.14) said it best – or at least first: “Make haste slowly.” Probably was talking about chariot racing. Today’s version of that same quote is: “Slow down to go fast.” At first blush that sounds contradictory, but you will learn that it is not.
In this article, designed for novice drivers or as a non-technical refresher for others, I’ll overview (and perhaps oversimplify) a few car control concepts and techniques you need to understand and apply to begin developing the car weight control, balance and smoothness that will reduce your track times.
As Dean Lewellen pointed out a few issues ago all of the control of your car comes through the four “contact patches” where your tires meet the road surface. Running the best tires you can afford for the purpose (not necessarily the most expensive) is important. Just notice that the drivers at the head of the autocross top time list are using racing tires. That doesn’t mean that you can’t have fun on street tires and occasionally do better than a driver sporting Yokohama’s or Kuhmo’s; but, to avoid too much frustration you need to compare your times against like-equipped cars.
Second on the improvement list after tires are suspension upgrades such as stiffer sway bars and an after market Camber Truss. Note how the faster cars run “flatter” with less body sway. When you think about it, all suspension improvements are for the specific purpose of keeping the contact patches aligned with and on the racing surface as much as possible.
Sway bars control the movement of the car’s body over the suspension system limiting the amount of weight shift during cornering. This makes the car more stable by reducing the unpredictability of body sway and better controlling or balancing the weighting on the tire contact patches. (I said I was going to oversimplify!)
A Camber Truss (you’ll find it in the front trunk of a 911 or engine compartment of a 944) bridges the front suspension towers and keeps the front bodywork from flexing too much. Flexing is bad because it unpredictably changes the way the tires meet the road surface (camber) under differing loads. A Camber Truss gives the front end a more solid, stable feel, although its contribution to handling performance is probably minimal. Looks cool, though.
Shock absorbers dampen the vertical movement of the wheel and tire on bumpy and uneven road surfaces keeping the contact patches on the road surface as much as possible. As high performance automobiles, Porsches are equipped with excellent shock absorber systems, which are quite effective for all but the highest performance racing needs.
I still have the original Bilsteins on my ’81 SC and they are quite serviceable at 91,000 miles including lots of track and autocross time. I will change them out soon, but only because I need to replace a worn suspension strut assembly. Remember my “while were in there” theory of maintenance? Of course they need to be changed in pairs, but why have new shocks only on the front end? What about balance? My mechanics love my theory!
Well, so far all I’ve talked about are mechanical suspension systems and it may sound like you need to keep the weight even over the tire patches in all situations. Au contraire! While you want the car’s systems to be relatively stable, balanced and predictable, you the driver need to manage the amount of load on the tire patches using the brakes, throttle and steering wheel to wring the greatest performance from your Porsche.
For discussion purposes -- at equilibrium -- that is, not accelerating, decelerating or turning, think of the tire patches as essentially equal and stable in size. Of course, there is a difference between the size of the front and rear patches based on tire width and front-to-rear weight ratio for rear, front and mid-engine cars. (A side thought: How many other auto manufacturers have built modern rear, front and mid-engine cars?)
Okay, what happens during braking? The load shifts forward increasing the weight on the front wheels and increasing the size of the front contact patches. Under acceleration the opposite occurs with the weight shift to the rear (love to see those 911’s/930’s squat) loading the rear tires and enlarging the contact patches thus providing more grip. In a constant velocity right turn or left turn the left side and right side patches, respectively, would become larger.
Consider braking or accelerating during turning and you might envision a slightly different tire patch footprint for each wheel. Of course modern suspensions do a pretty good job of balancing these loads, but if you’ve aggressively driven an older car with a “soft” suspension, you’ve experienced disconcerting body sway and unequal loading.
Okay, so how do you make this contact patch knowledge work for you? Well, now that we understand the suspension’s contribution we need to focus on that loose nut behind the wheel. It stands to reason that abrupt control movements will decrease the stability of the vehicle by “tossing” the weight around. For example, when do you need more grip from the front tires? When turning, so you may ease off the throttle or lightly touch the brakes to “set” the car weight forward before entering a turn. It can be a fairly subtle maneuver. (You can also “trail brake” but that is the subject for another article.)
When accelerating out of the turn, if the back end gets “loose,” i.e., slides to the outside of the turn (oversteer), what do you do? A green driver will get off the throttle abruptly (been there, done that) or hard on the brake, which will shift the weight and grip forward when you really need it at the rear. What happens next? Right, a spin! While it seems counterintuitive (that means scary to do), applying some throttle will weight the rear wheels and contact patches and if you are not too far gone and have enough track left, allow you to drive out of the slide.
That is the purpose of skid pad practice where one drives in a circle, increasing speed and learning to control the car with throttle to keep moving forward. The Bondurant School does an excellent job of teaching this method of car control. While it is easier to do on the wide open skid pad, it is sometimes scary to apply the technique at speed on a road course. When you feel the back end coming out the intuitive reaction is: “I’m going too fast -- slow down, quickly.” So build up your skill and confidence slowly while expanding your comfort zone by carrying more speed through the turn and using the brakes very sparingly.
And remember should you err: “When in a spin – both feet in!” Don’t try to over-control and “save it” which may result in a counter-spin eating up more safety space and putting you further out of control. Just put the brake and clutch to the floor and ride it out. The car will tend to spin in the direction it was going. As Cedric the Entertainer says to his soggy girlfriend in those beer commercials: “It ain’t so bad!”
How smoothly you move the steering wheel also contributes to increasing your speed. You are familiar with the terms “understeer” or “push” when the front wheels are turned and the car continues moving straight ahead. In that case you are scrubbing off speed. Many years ago when brakes were far less efficient than today some drivers would “saw” (move back and forth rapidly) the steering wheel before entering a turn to help scrub off speed. Better to be slightly slower and smoother in the turn creating the minimum front tire sideslip or friction.
When accelerating out of a turn you should gradually “unwind” the wheel allowing the car to drift out to the edge of the track instead of holding the wheel into the turn and exiting in the middle of the track. One of the reasons instructors advise students to “use the whole track” is so they can keep the speed and momentum up by keeping the front wheels relatively straight ahead.
Okay, so how do we put this all together? What does “slow down to go fast” really mean? Generally speaking, the more smoothly you accelerate, brake and turn while maximizing your speed and minimizing unnecessary friction or contact patch sideslip the better your times. Remember, smoothly doesn’t necessarily mean slowly. You need to be quick and smooth. Of course, I haven’t talked about the critical importance of driving the best line, but that, too, is the subject of another article.
A smooth, fast lap in autocross is not as flashy, nor does it usually “feel” as fast to the driver as a smooth, controlled lap. In addition to being a little slower to learn a new course marked with cones, I tend to be kind of hyper at the beginning of an autocross session, don’t follow my own advice, and gradually exert more self-control as the day goes on. That’s why I’ll often log my best time on the very last lap available. It focuses my mind when it is the last chance. So I say to my fellow IS Class drivers (you know who you are, Bob Frith), no I am not sandbagging, I just need to learn to listen to my inner voice of reason earlier.
Even though a properly driven fast lap in an autocross may not feel as “fast” or satisfying to the driver from a physical standpoint, the ultimate satisfaction is seeing a lower lap time posted among your competitor’s. That’s why I join that historically overlooked driving instructor, Emperor Caesar Augustus, in recommending you learn to “Make haste slowly!”
By Dale Willis
Okay, so you are new to autocross or have just tried your first road course during a Driver’s Ed event at Firebird East or Pinal. You’ve found you can do most short autocross courses in second gear (depending on your car), but the longer autocross courses and the road courses require gear changes. Shifting up through the gears is no problem – you do it every day and a smooth, positive upshift is like second nature to you. Downshifting may be a little more problematic and a less than natural activity, however. A well-executed downshift allows you to smoothly enter and exit a corner in the proper gear to produce maximum acceleration in the next segment of the course. This requires mastery of what is called “heel and toe” technique, which will allow you to smoothly shift to a lower gear while maintaining maximum braking – without upsetting the balance of the car.
Heel and “toe” downshifting is a misnomer --it really should be called “heel and ball” or “ball and side” (of the foot). Toes have nothing to do with it. The latter two terms are not as catchy, huh, so we’ll stick with the common name. You probably already know what happens when you don’t use this technique: You brake going into a turn, depress the clutch, downshift and release the clutch. The car nose-dives, the rear wheels lock up momentarily due to engine compression braking and, if you are turning, you may be in a spin. At the very least you’ve over stressed your drive train and engine and lost whatever momentum you had going into the turn.
There is an easier way! It just sounds more complicated. Really!
The objective of heel and toe downshifting is to match the speed of the engine with the speed of the gear you are selecting (think rear wheels) by -- while braking with the ball of your foot -- rotating your heel to stab or “blip” the throttle bringing the revs up to the appropriate level. What is the “appropriate RPM level?” Depending on your car it is usually several hundred RPM higher, but it is something you must develop by feel, by ear and by experience, not by watching the tachometer. Too much RPM and the car lurches forward, too little and the tires chirp and you nose-dive. Just right, and it is just like “buttah.” A smoothly executed heel and toe downshift is third on my list of “most fun things you can do with your clothes on.”
It is important to remember that you should be using the brakes to slow down and not using the engine compression to slow. Using the engine to slow down makes brake modulation more difficult and upsets the balance of the car that you are trying to achieve through smoothness. Okay, I use engine compression all the time on the street to hear the burbling and popping of my exhaust, but it is not a good technique for the track. It is a good way to get a feel for RPM-matching on the street, however, while satisfying your sonic urges. (I feel sorry for you guys with quiet cars!)
Now, when you try this technique you will probably find that your ankle is not flexible enough to get your heel down far enough to “blip” the gas pedal while the ball of your foot is on the brake. You don’t have to be a ballet dancer, but it helps! The solution is a minor modification to the throttle pedal to bring it slightly below the brake pedal when the brake is depressed. You can build-up the throttle pedal about ½ to ¾ of an inch several ways: There are commercially available replacement and clamp-on, adjustable throttle pedals (check Porsche Panorama and Excellence Magazine) for $100-150. Some versions have an extension below the brake pedal so you don’t even have to rotate your heel. A more economical solution is to purchase a conventional, stock throttle pedal and mount it to the existing pedal using spacers to suit. Care should be taken so the built-up pedal is secure and free in travel.
What about that other heel and toe description I used: “ball and side?” The cockpit area on Porsches gets tight near the pedals and if you resemble “bigfoot” there may not be much room to maneuver your heel. An alternative technique is to slide your foot slightly to the right on the brake pedal so that ½ to 2/3 of the ball of your foot is applying the brake pressure. To blip the throttle, simply roll your foot so the right sole/edge of your foot pushes the throttle. Both techniques require some practice and, in each case, after blipping the throttle your foot should smoothly rotate to normal braking position.
Just as in life, timing is everything. One challenge of heel and toe is to constantly maintain consistent braking pressure while your heel or the side of your foot is doing its thing blipping the throttle. Additionally, you can’t freeze and forget to quickly and smoothly release the clutch pedal while the RPM is up. Let the RPM drop and you are back where you started. While you are learning it may happen occasionally until you get the feel for the timing.
When to downshift? At the approach to the corner just before you turn in – brake first and then downshift – to be in the proper gear and at the best RPM to maximize acceleration out of the turn. This will also allow you to concentrate on executing the turn without too many timing issues. However, you should work towards shifting at the last possible moment before turning in.
To learn more about heel and toe downshifting and high performance driving in general, check out Secrets of Solo Racing by Henry A. Watts, High Performance Driving by Bob Bondurant and John Blakemore and Speed Secrets by Ross Bentley.
If at first you feel frustrated, remember the advice given to the street-direction-seeking tourist when he asked, “How do I get to Symphony Hall?” The reply: “Practice, man, practice!”