Corvette Autocrossing

Have you ever wondered what exactly an "Autocross" is?  An Autocross/Slalom/Gymkhana is a timed driving event that is run on a course marked with highway cones.  While the speed at which a car negotiates the course is always up to the driver, there is never any obligation for drivers to drive their cars any faster than they feel comfortable at driving.  Winners are determined by the lowest elapsed time for negotiating the course.  Winning times between competitive drivers can differ by as little as hundreths of a second, so elapsed course times are very important.

These courses test driving precision at relatively low speeds.  Courses consist of tight turns and short straightaways which intensify the illuison of speed on the highway cone-marked course.  But precision is paramount.  Each highway cone that's hit and moved costs drivers a two-second penalty; going off the course gets a 20-second penalty.  Competitive drivers virtually cannot make up the time lost to such penalties, so the qualities for good autocross drivers emphasize precise driving talents more than just a heavy foot on the gas.

It also allows drivers of all types to explore the limits of their cars with minimal consequences.  Race car driver, Mark Donohue said "the best way to learn your limits is to exceed them once in a while."  In either race driving or street driving, losing control of an automobile and going off the road at speed can have dire consequences.  On an autocross course, drivers can do little more than run over a couple of highway cones.  Virtually every racing school and high-performance driving school in the U.S. uses autocross-type courses as they train novice drivers how to go fast, because novice drivers can make mistakes safely without endangering themselves or others.  Police departments with driver training programs use pylon courses for training drivers in high-speed pursuit for much the same reason.

Best of all, you can learn these lessons in the car you drive on the street everyday, provided it is equipped with seat belts and is in safe driving condition.  Safety is a high priority for autocrossers.  Technical inspectors check over each car to make sure it will be safe on the course, and drivers are required to wear a motorcycle or racing helmet and their seat belts as they make their runs.  But other than that, anyone with a valid driver's license and a safe automobile can take a crack at a challenging autocross course.

All About Autocrossing - by Lloyd Loring, South Bend Region, SCCA

On any summer Sunday, you may see a local parking lot barricaded off, with traffic cones strewn about and cars lined up to drive around, (but not over) the bright orange cones as quickly as they can.  What you are seeing is an autocross, also called a "Solo II" when sanctioned by the Sports Car Club of America.

The game is simple:  the quickest cars, win.  Any licensed driver with a safe car and a helmet may enter for a modest entry fee.  But like any other sport there are some rules.  The rules are simple, mostly intended to insure safety and fair competition for all drivers.  Let us take a close look at this increasingly popular sport, to see how it works and why it is so attractive to drivers.

Start with the course:  a large, unobstructed paved area that permits setting up a miniature road racing course using traffic cones to outline the route.  The car must follow the course correctly; each cone knocked down or moved costs two seconds of time penalty.  If the driver misses a section of the course, the run is not scored at all.

Each course is different and must be approved by a safety steward who checks that there is room for error and there are no obstacles that could hurt the car, driver, or spectators.  The event is designed to limit top speed, and most drivers never get above second gear during their run.  As a result, Solo II is one of the safest automotive speed sports.

Drivers run alone on the course (hence the name "Solo") with no wheel-to-wheel racing.  On larger courses, you may see more than one car on the course at a tiome, but with cars separated for safety.  Each entrant is timed on every run to the nearest 1/1000 second by electronic timers that can handle up to four cars at a time.

The courses are designed to challenge the driving skills and car preparation of the entrants, with turns, slaloms, and gates that put a premium on car control and accurate driving.  To take full advantage of the course, most contestants walk the course several times before they run, planning their "lines" and looking for a time advantage wherever they can (there are no practice or qualifying runs prior to the timed runs at a regular Solo II).

A word about the drivers.  Generally, they are sports car enthusiasts who enjoy this opportunity to drive hard and smart, and seek out the chance to compete against other drivers in the sport.  They come from every walk of life, and both sexes are represented.  Because the sport may be enjoyed at modest cost (tires may be the biggest single expense) it is not limited to an elite group.  One unique aspect of autocrossing is the absence of specialized workers and officials.  The drivers are also the officials, and are required to work some portion of each event.  This cooperation makes autocrossing one of the friendliest forms of auto racing.

You'll see all kinds of cars at an autocross.  And it is obvious that they are not all equal in speed potential.  To solve this poroblem, the SCCA has created 25 car classes in four major groups, with 25 parallel ladies' classes.  Each class runs for its own trophy, although at smaller events, the classes may be combined.  The four major groups are Stock, Street Prepared, Prepared and Modified.  Each has its advantages and proponents and they are all hotly contested.

The Stock category is the largest group with 9 classes.  Cars are permitted only minor changes from original showrrom condition.  The stock classes include Super Stock and A-Stock through H-Stock.  Late model Corvettes dominate Super Stock, while H-Stock contains small economy 4-door sedans, with everything else somewhere in between.  The classes cover sedans, sports coupes, all-out sports cars, front- rear- or all-wheel drive, and from ttree to twelve cylinders.  In short, the full range of modern street cars is found in the stock group.  And because the cars are grouped by actual speed potential, older cars can remain competitive in the sport.

Perhaps a driver has altered the car by using an exhaust header, wider wheels, or other minor changes intended to improve handling or speed.  This will probably put the car in one of the five Street Prepared classes.  This group includes only production cars capable of running on the street despite their modifications.  But if the driver wants to go even faster, six Prepared classes await.  These production cars are permitted major engine, suspension and body modifications and racing slicks.  Most are similar to the cars seen in the SCCA road racing Production and GT classes.

For the ultiamte thrill, five Modified classes are available.  These are potentially the fastest cars of all.  They range from tiny single-seat formula cars, (minitature Indy cars, if you will) with a variety of highly-tuned powerplants (Volkswagen, Ford, Pontiac, Chevrolet, Mazda, etc.) to wild hybrids and purpose-built cars with extra-wide racing tires and very sophisticated suspension systems.  Here, car design and selection are as important as driving skill, but the potential of these cars puts an extra premium on experience and racing knowledge.

A day at a typical local Solo II will see the course set up early, then registration and safety inspection for the participants, followed by course walks for drivers.  After a brief driver's meeting, one roup of drivers will line up for their turn while others take their work stations on the course to pick up and record pylons knocked down, or in timing or other tasks.  After one or more runs, the drivers return to their "pits" and the other drivers run, alternating until all drivers have at least three runs on the course.  Each run is timed, and the fastest single run by a drivers is his "score" for that event.  When all runs are complete, trophies to the best drivers are handed out and pylons and other equipment will be packed up for another day.

In addition to local events, "premier" events are staged througout the country, many featuring two days of competition.  A number of major series, including a national "SCCA Tour" series, let drivers compete against the best in their area.  In the Midwest, the Yokohama Cendiv Championship Solo Series and the Tri-State Championship Series are perhaps the best known and most popular, with more than 200 drivers attending many of these events.  In September almost 700 drivers from all 50 states and Canada descend on Salina, Kansas for a four-day shoot out on two courses to determine the National Champions in each of the 50 classes.

Pro Solo is a national SCCA series that offers prize money and unique dual courses that permit drivers to compete side-by-side, much like a drag race with curves.  The elimination format also features handicapped starts based on times earned earlier during the weekend, resulting in very close competition.  In addition to the prize money, entrants are also supported by contingency awards that are attractive to many non-professional drivers.

The appeals of autocrossing and solo competition are many.  You can drive as hard as you can without feat of arrest, and with little real hazard.  You get the adenaline rush of competition even in your own daily transportation.  And costs can be scaled to meet you needs.  With hundreds of events in the Midwest alone, competition is nearby and frequent.  It is truly grassroots racing that lets the widest range of drivers enjoy all that their cars can offer.

What It's Like to Drive a Solo II

You are sitting on the starting line, revving your engine in little "blips" that reflect the way your stomach feels, when the Starter asks if you're ready, then sweeps the green flag down and you're off!!

With a squeal of tires, and a roar from your engine you head away from the line and start to gather speed.  Suddenly, what seemed to be a simple layout of pylons in a peaceful parking lot becomes an absolute maze of obstacles that looks nothing like the course you had just walked.

Autocross Preparation

Basic Car Preparation

The first thing you want to do is to make sure your car passes the tech. inspection.  This is strictly a safety inspection designed to protect you and your car.

• Remove everything loose and/or removable from the car.  Including the spare tire, jack, trim rings, caps, etc.  This prevents things from flying around when you are cornering hard and will also reduce your weight.



• Increase tire pressure to at least 35 psi.  40 psi may be even better.  While you are doing this, also check to see that all lug nuts are tight (75lbs/ft.) and in place.



• Make sure your seat belts fit properly and are in good working order and do not restrict your movement when steering.



• Be sure the steering does not have excessive play and that the brakes do not grab or pull.  Make a stop at 20 mph with your hands off the wheel.  The car must stop in a straight line without pulling to either side or locking up a single wheel.  The wheel bearings on all wheels should also be free from excessive play and the ball joints must not show signs of excessive wear.



• Check all fluid levels and inspect for leaks.  Brake master cylinder must be within 1/4" of full.  The brake pedal must be firm and set high enough so that it does not touch the floor under maxium braking conditions.  All brake lines must be solid and able to withstand the maxium brake pedal force that you may apply.

Other Things to Consider Before Driving

• Have either a full or nearly empty gas tank to minimize the effect of gas sloshing back and forth while cornering.



• Increase the engine idle speed to 1000-1500 rpm to keep it from stalling under rapid acceleration or deceleration driving conditions found in an autocross.



• Remove the air cleaner element but not the housing to increase the air flow.  The air cleaner housing must remain secured.

Basic Driver Preparation

• Buy or borrow a good, well fitting helmet.  You must have one to drive.



• Wear comfortable shoes that will allow you to feel the pedals.  (Heavy work boots are not recommended!)



• Wear loose fitting upper cothing so that your arms can freely turn the steering wheel.



• Learn the course.  Arrive early and walk the course, looking for the fastest line throught it.  Watch experienced drivers drive the course, making note of where they place there car and where they accelerate and brake.

Basic Principles of Driving

• Drive smoothly.  A driver who does not make any jerking motions with his car can drive any portion of the course faster than one who does.  That's why some of the fastest drivers don't look fast when you are watching them.



• Always have your foot on the gas or the brake.  Don't ever coast.



• Turn as much of the course into a straight line as possible.  As good as Corvettes are at cornering, they're even better in a straight line.



• Keep wheel spin and tire noise to a minimum.  Although it may sound impressive, when you have tire noise you are loosing traction and momentum.



• Don't lock up your wheels when braking.  Locked up wheels do not stop you as fast as nearly locked wheels.  If your car is not equipped with ABS brakes, pumping the brakes often helps.



• Keep braking to a minimum while cornering, a car's ability to corner is reduced when the brakes are being applied at the same time.  You should try braking before a corner and then accelerate while going through it.

These are only the basics.  These rules, if followed, will help you become a good autocrosser - and noticed, you haven't spent any money if your car is in good condition to start with.