BC Corvette Club Autocross Sept 25

By Dick Rasmussen

[GGLC member Dick Rasmussen is a two time SCCA Solo II National Championship (one of which was in a near stock Twin Cam Europa, his current autocross car, in class A-Street Prepared, a class allowing for very well prepared Porsches) plus he won too numerous local, regional, state, divisional, and Pro Solo championships to list. Auto-X Magazine did a feature story on the author and his autocross career. This begins a three part series by Dick sharing his thoughts on autocrossing. However, it should be noted that Dick's ideas and practices apply to not only autocrossing, but road racing, vintage racing and even street driving.]

The sport of autocrossing is enjoying a surge in popularity unprecedented in its history. It is becoming "Big Time" as evidenced by a magazine for the sport, books and videos on how to drive faster, tire company semi's at events, tires designed specifically for autocrossing, commercial autocross driving schools, a professional series, lots of sponsorship and contingency money, and a recent National Championship event at which the total value of the cars for ONE street legal stock class approached ONE MILLION DOLLARS! Even a major DRAG RACING magazine has done an excellent article about autocrossing.

Autocrossing has become more complicated than it used to be and the level of competition has gotten so intense that it is very easy for new autocrossers to become overwhelmed by all the things they need to learn. The purpose of this article is to summarize much of what is covered in more detail in other places and to pass on some of the lessons I've learned (many the hard way) in over 12 years of serious autocrossing. Topics include practice, driving techniques and car preparation.

Autocrossing is a chance for people who enjoy driving to drive at or near a car's limit with little risk to their bodies or their finances. In addition it can be a competitive outlet and/or a chance to develop and show off driving skills and technical abilities. In other words, it is a sport and a hobby for the majority of participants and therefore should be FUN!

A quick second gear slalom or a series of offset gates which allows a skilled driver to make a car literally "dance" can be exhilarating, as can the thrill of learning how to catch an impending spin in a sweeper by applying more gas and a little counter steering. Knowing how to get on the power after a corner sooner than anyone else is very satisfying and can help win championships.

Most of the suggestions in this series are directed towards making it easier to drive fast enough to get a thrill and to feel good about how well you did while reducing the number of frustrating mistakes which detract from having fun.

The most important element in autocrossing is the driver! Therefore, let's start with driving tips.

During a Tracktime Driving School at Charlotte Motor Speedway, IMSA racer Amos Johnson was asked how he knew he could safely drive an unfamiliar stock sports car through the high banked NASCAR turns 3 and 4 so "fast". Amos replied, "It never occurred to me I couldn't." Amos could say this because his experience allows him to almost instinctively determine a car's limits and he knows he can recover from reasonable excursions beyond the limits.

To become consistently competitive against tough competition you too must instinctively drive very close to the limit and must be able to quickly and neatly recover if you overestimate the limit.

The only way to develop and maintain the needed skills is through practice. The following are some ideas that have worked for me which make practice more effective.

Practice includes three important aspects. One is pushing the car harder and harder under controlled conditions until you bring your limits up to the car's limits. Call this "calibrating the seat of your pants".

Second is repeatedly driving at or slightly above those limits so you get very used to what they are and how to recover from exceeding them. This repetition gives you the ability and confidence to "easily" drive near the limits in competition.

The third is trying different driving techniques to see which work the best. This does not include trying changes to the car. Experimenting with the car setup is "testing".

Begin by identifying the elements to practice such as slaloms, sweepers, braking, and shifting. Next find a place to work on one element at a time. Fortunately most autocross elements require very little space and speed and can, therefore, be done on weekends in empty industrial/office building parking lots with very little risk to your license or your car and, if you are careful, NO risk to other people.

As you begin practicing, GRADUALLY but steadily push the limits as you know them. Remember that until you get the tires sliding or spinning you haven't reached their limit. Once you finally exceed the limit, practice recovering. Keep in mind, however, that in autocross competition you DO NOT want to exceed the limit on purpose except in rare circumstances. What you are trying to do is find the limit and learn how to deal with inadvertently exceeding it.

When experimenting with technique, time the different techniques so you really know which worked better. A G-Analyst is probably ideal, but a stop watch is OK too. Try different lines. See how close you can get to pylons. When driving on wet roads with little traffic, try looking at your tire tracks in the rear view mirror. With practice, you can learn to put the tracks, and therefore your tires very close to lane lines, the shoulder, or any other reference mark on the pavement. Knowing where your tires are can save a lot of pylon penalties! In transient (very rapid change of direction) situations, such as slaloms and offset gates, get a feel for how the car feels just before you lose it so that in competition you can slow slightly before it's too late. Try using different gears in borderline speed ranges. See how the car handles in first gear versus second gear in a slalom. Determine whether you can use the extra power the lower gear gives you. See how much speed you really gain from accelerating for a few car lengths in a higher gear versus staying in a lower one and easing off the gas to stay at the engine redline. Every shift takes time and distracts from important aspects of driving at the limit. Each shift also increases the chance of making a mistake. Therefore, you only want to shift if the benefit is worth the cost and the risk.

Even though you are practicing, not testing, be aware of changes in the car, the pavement, and your driving which can be affecting times. It is important that you know what really caused each difference. Be analytical, be calm, take notes, and above all, be honest with yourself. Convincing yourself that you've found the fastest way when you haven't won't win autocrosses.

Well focused and executed practice really can make a difference. Before my first Nationals the published course map made it clear there would be "problems" I had never encountered. To prepare, I found places to simulate the problems and practiced and experimented extensively. What I learned made the difference between winning and losing. It can for you too.

THE "LINE"

The correct line is essential to getting the best possible run time and can easily make a difference of several seconds on a long course with many corners.

Driving the correct line involves more than placing the car on the correct portion of the pavement. It requires being able to do so while driving the car at or near its cornering, braking and acceleration limits despite unfamiliar course designs, pavement conditions, and car handling characteristics.

In autocrossing, essentially all corners including slaloms should be driven with a "late apex" line as shown in the drawings. As you pass the apex, you should already be as close to full throttle as the course will allow. The other types of cornering lines used in road racing rarely if ever are appropriate for the tight confines of autocross courses because they either result in a high number of time consuming mistakes or they are slower.

A major reason for using a late apex line is that it results in far fewer mistakes than does the use of early apexes. This is true on all courses but is much more apparent on relatively tight courses with lots of slow, tight turns. Many drivers make the time consuming and pylon eating mistakes which are guaranteed to result from not using late apexes in tight corners. Drivers will clip a cone with the car's inside rear tire because of entering too close to the inside of the corner (early apex) and then will have to creep around the rest of the corner before finally getting the car pointed down the next straight. In many instances the car may also hit pylons with the outside front tire or bumper because the driver's line and/or speed simply do not leave enough room to make the turn.

Because even the most open autocross courses are extremely tight compared to any race track, in many instances the exit of one corner is the entrance to the following one. With no straight in between there is no chance to move from the "wrong" side of the course to the "right" side before the next corner. It is extremely important in autocrossing to give up a little exit speed from one corner, if necessary, to allow the proper line for the next corner. A late apex line permits this approach while an early apex line is likely to prevent it. It is very common to watch drivers get in more and more trouble as they progress through a course because they either cannot or will not move to the correct line.

Even if an early apex line is somehow executed with no mistakes, for most cars a properly driven late apex line seems to be faster. After years of watching many National Champion caliber drivers from close range I cannot recall anyone who commonly used an early apex.

In order to drive a late apex line, you must slow the car down in time to turn at the proper place. Even for the most skillful autocrossers, picking the latest possible braking point is extremely difficult because we do not get to practice on the course. I have found that being conservative and braking a little earlier than may be necessary adds much less to a run time than does braking a little too late. It also allows some "cushion" in case traction is less than expected or speed is still too high. When in doubt, brake early and if you determine it was too early, try a slightly later braking point on the next run.

If downshifting is necessary for a corner the shift should be finished, with the clutch back out, BEFORE beginning to turn. Very few people can corner at the car's limit while steering with one hand. Even fewer can shift instantaneously. Shifting while braking will result in fewer "errors" than shifting while cornering. Even more important it allows you to already be applying power when you pass the apex which means you can start accelerating much sooner. Most cars also handle better and give the driver more control while accelerating than while coasting or braking.

Finally, it is extremely important that while walking the course you plan the line you intend to use because once you start driving it will be too late to figure out the correct line and how to actually get the car on it. Not only must you memorize the course, you must decide exactly where the correct line is through all portions of the course. You must also decide approximately where to brake and where to shift. This can be very hard to do when you also want to socialize with your friends but it is essential! Try to limit the socializing to one walk through lap and then get serious for two or three other laps.

The line and techniques described here may conflict with those suggested by other writers. However, they have worked extremely well for many successful autocrossers so whether you are struggling to become reasonably competitive or are trying to find the edge to allow you to win, I recommend that you try these techniques to see if they can work for you.

To quote a recent Yokohama Tire "Famous Amos" ad, "A driver is only as good as his car." So far in Autocrossing Tips I have been concentrating on getting drivers as good as their cars. This is because even though a slow driver may go faster in a faster car, he really cannot determine how to properly set up a car to go faster unless he is driving very close to the car's limit and knows what it is doing at the limit. Now it is time to cover some ideas on how to make the car as good as its driver has hopefully become.

Unfortunately for people who are not technically inclined, car preparation and improvement is a very technical subject. There are some very good, very thick, very complicated books available about car preparation which I have read many times and still don't fully understand even though I'm an engineer. Fortunately autocrossing in stock classes does not require much more than a good feel for what the car is doing right or wrong and a knowledge of some basic principles of what to do to correct problems. If you want to compete successfully in the other classes, you'd better either learn the technical stuff, get excellent advice, or hire someone who knows how to set the car up for you.

This article is not intended to cover major changes such as different springs and sway bars, engine modifications, etc. I'll leave that to the books noted above. It does cover some basic principles of autocrossing preparation which I've picked up over the years.

Preparation starts with making sure the car is running right, the throttle opens all the way, the fuel and air filters are clean, there is enough fuel, oil and water, and the engine pulls smoothly through its normal rev range. You should use a stopwatch to measure and record benchmark acceleration times for various rpm and/or speed ranges so that as the car gets older or you make changes you have a reference for comparison. This is especially useful to reassure yourself just before a big event that the car is still healthy.

Once the car is running properly, tires are the next most important part of car preparation for autocrossing just like they are for all other forms of "racing". If at all possible, anyone running street tires on a car that sees significant street use should have an extra set of wheels for tires which have been proven successful at the SCCA Solo II Nationals. In race tire classes, fresh rubber is as important for autocrossing as it is for racing. Used race tires may be cheap but they are not the way to find out how good you are. In the rain all but the very lightest cars are better off on their best dry competition tires than on deep tread lower performance tires.

Test the brakes to make sure they are not pulling or locking up one or more tires. If brake balance is off, there are many ways to adjust it (see the "books"). In stock you can try different brands and "hardnesses" of brake linings and pads. Remember to stay with street compounds since race compounds need to be warmed up too much before working to be useful for autocrossing or street driving.

Check the general condition of the suspension and make sure nothing is broken or loose and that all bushings are in good shape.

Watch out with shock absorbers. It is fairly easy to get the front shocks too stiff creating "understeer" or the rears too stiff causing "oversteer" or excessive "wheelspin". However, some front wheel drive cars seem to work with very stiff rear shocks. Since shocks are expensive and frequently hard to install, I recommend thorough research prior to purchase.

Make sure the front suspension alignment is appropriate for your type of car. Most street tires like as much negative camber and positive caster as the rules will allow in stock and street prepared classes. Exceptions may be very wide low profile tires on cars with excellent suspensions such as late model Corvettes, IROC Camaros, and Trans Ams.

The experts are recommending one-sixteenth to one-eighth inch toe-out these days for cars which normally run toe-in. I haven't done any testing to compare different settings. However, my guess is that it is much more important on a car like a Mustang V8 which keeps a lot of weight on the inside front tire in a tight corner than it is on a mid- or rear-engine car which picks up the inside front tire in tight turns.

Be careful with toe-out on the street since it may cause instability at highway (or above) speeds. If you figure out how many turns of the tie rods it takes to switch between street and autocross settings you can adjust toe easily without alignment equipment.

Some independent rear suspensions have adjustable alignment. More negative camber is probably a good idea since it will help cornering but be careful because you may create too much wheelspin in a rear wheel drive car. Be very careful with rear toe unless you really know what you are doing. The books say (I have not tried it) that rear toe-out is very unstable.

Many autocrossers over-emphasize the importance of minor changes in street tire pressures and fool themselves into thinking they can feel a couple of pounds difference. Start with what the tire company or a fast competitor in a similar car recommends. Then check to be sure the tires are rolling all the way to the edge of the tread but not onto the sidewalls. If they aren't rolling under far enough, don't lower the pressures, drive harder! If they are rolling too far, try more air. In some cars you will not be able to completely avoid sidewall scuff.

Unless your car is grossly underpowered in a class where it is legal to make major horsepower improvements, power is not as important as traction and handling. Responsiveness (i.e., not bogging or stumbling) and the flexibility to minimize the need for shifting are much more important.

Since we get little or no chance to make more than minor changes at an event, the car should be set up for an "average" course. If possible, a car should not require "tossing" or "pitching" into a corner. Even if you are the extremely rare driver who can toss a car well consistently, there are too many corners on most autocrosses where it simply cannot be done. Conversely, the car should not spin at the slightest provocation. Such cars never let you feel confident. Plus if they are rear wheel drive they probably have too much wheelspin.

Different driving styles and ability levels can result in understeer for one driver and oversteer for another in the same car. Keep in mind that as you get faster or experiment with different lines your perception of the car's handling balance will probably change.

Whenever you make a change to the car, you must test it. Make one change at a time and make sure any performance difference is a result of the change and not some other factor such as tires, dirty course, driver error, etc. Remember that modifications do not necessarily help, despite what "everybody" says or assumes. Any professional racer can give plenty of examples of mods which either had no effect or slowed the car. Watch out for setups which only work if you don't make any mistakes.

Perfect runs are very hard to come by in autocrossing. A slightly slower, more forgiving setup will give you the confidence to drive closer to the limit than one which "bites" if you overdrive slightly.

One of the most critical aspects of car setup in any sort of racing is finding the optimum balance between corner exit understeer and corner exit oversteer. Too much of either ruins lap times. Try to find the combination of car setup, driving style and cornering line which allows you to brake hard, turn the corner, and then get to full throttle as soon as possible without making mistakes you cannot easily correct.

In my opinion, corner exit is the single most important factor separating consistent winners from the rest of the pack. Given otherwise equal cars and drivers, the driver who gets to full throttle first will win!

This article is the last of the series. I hope this helps make autocrossing fun for you. Remember that this is only a summary and doesn't cover everything you need to know to make you and your car as fast as possible. If you want to win against tough competition, you'd better plan on learning much more than these articles have covered. Besides, you don't think I'd give away ALL my secrets, do you? I STILL WANT TO WIN!

-----------------------------------------------------------