The PDX Corner - Part II.

by Ken Berchak

In the last article, I stated that this article would deal with the car. In that article I stated that the best car for a PDX (novice) is a run of the mill econo box. This still holds true, but then there is reality.

OK, so you don’t have an econo box, then bring out your Porsche GT3, Audi R-8 V10, Viper, Mercedes Benz AMG SLS, Ferrari 599, Lamborghini LP570-4, or what ever, as long as it complies with the SCCA Level 1 PDX rules.

The first thing to get the car prepared for the PDX is some general maintenance. The tech sheet is divided into twelve areas. Lets look at each one.

First on the list is ROAD EQUIPMENT. This consists of brake lights and windshield wipers. Make sure they both work.

Next is SUSPENSION. This group of items are normally checked during a wheel alignment. Steering wheel free play, steering linkage, wheel bearing play, steering assembly attachment points, tie rod ends, and shock absorbers. These inspection points must be within factory specs for safe operation.

Third on the list is the BATTERY. It must be securely mounted and the positive post needs an insulated cover.

Fourth on the list is the ROOF. If the car is a sedan (2 or 4 door) this is an N/A, i.e., does not apply. If it is a convertible or Targa top the top must be down, latches secured and the roll bar must be above the drivers/instructors head. If you have questions about this area, check with a PDX official, or PDX tech inspector.

Item five on the list is BRAKES. This area is my biggest concern. The tech inspector will check brake fluid level and how clean the fluid is, i.e., has the brake fluid been recently changed. It is recommended that the brake fluid be flushed and replaced within 90 days of the event. The reason for this recommendation is that brake fluid absorbs moisture from the air. Water in the fluid lowers the boiling point. Since the brakes will be working extra, the heat load can cause the brake fluid to boil resulting in the loss of brakes, not a good thing to have happen. A proper fluid change will result in a firm brake pedal. If not then the brake hoses may have softened and need replacing. The rules require at least 3/16 inch brake pad thickness. This, in my view, is bare minimum. To be safe and maximize your fun factor, I strongly recommend the installation of performance brake pads. There are pads on the market that will work on the “street or strip” which are capable of operating at the higher temperatures generated during a performance driving event. Additionally, using a performance brake pad will ensure that you have brakes for the trip home. Next in this section is the rotors (drums). The rotors must not have ANY visible cracks or heat distortions. You don’t need a thumping brake pedal from a distorted rotor or cracks that will cause the rotor to shatter under the heat load. The last item in the brake section is the brake hoses - no leaks, this is a no brainer.

Although not in the proper order, the sixth item on the check list is MISCELLANEOUS. No loose items in the passenger compartment, or trunk area. The glove box door must be surely latched. If a tech inspector or instructor spots a loose item, be ready to remove it from the car.

Item seven - ENGINE BAY. No fluid leaks, a car leaking engine oil or anti-freeze causes the debris flag to be shown. Oil on the track will cause the cars following, and eventually you, to slip and slide in places that you don’t want to. Belts and hoses are to be secure and properly tensioned. A thrown fan belt will rapidly lead to an over heated engine with the accompanying expensive repair bill. The final item in this section is motor mounts. A worn motor mount lets the engine flop side to side or fore and aft in a front wheel drive car. This condition can and will break other parts.

Item eight - WHEELS AND TIRES. Next to brakes this is probably the most important area. The tech inspector will check for minimum tread depth. No less than 3/32 is recommended at the start of the event. You will wear it off. Wheels that use wheel covers must have the covers removed. Steel wheels flex in hard corners. Lost wheel covers may not be returned. Alloy wheels must not have cracks or dents. Lug nuts must be torqued. In fact it is a good practice to check the wheel nuts torque before each session on track. This is a standard practice for seasoned racers and cannot be over emphasized. Tires - must have at least a 120 mph rating. All performance tires have this rating. Tire pressure is not on the list for the tech inspector to check. Tire pressure has a direct input to the performance of the car in a corner. Autocrossers will set the tire pressure on the high side for an autocross event. The heat build-up over the short run will not effect the tires performance, hence the tire will perform will. In a PDX, the time on track (each session is 20 minutes) allows for the tire to heat up. The increased pressure caused by the heat build-up can easily over inflate the tire. At minimum, this will cause the tire to operate on a narrow strip in the center of the tread pattern. This condition limits the tires performance in a corner and greatly increase the tire wear. The objective is to have uniform temperatures across the tire at the end of the session. This tells us that the tread in contact with the road is maximized and working. Suspension setting will effect the tire temperatures so this guide line will have exceptions. I cannot state a recommended tire pressure for your car. The ideal cold pressure has too many variables to give a specific pressure. Check your tire pressures after each session while they are hot. One guide line is to have all the tires at the same hot pressure. Remember, the tire tread can drop 40 to 80 degrees on the cool-off lap, so using these guide lines may take several sessions to get the correct cold pressures.

Item nine - EXHAUST SYSTEM. The exhaust system parts must be securely mounted, no leaks (noise and exhaust fumes getting inside the car) and the exhaust must end behind the mid-axle point (normally not a problem for street legal cars).

Item ten - THE CAR BODY. No chassis weakening rust areas. The windshield must not have any cracks. Small stone chips, although allowed, can become large cracks as the car body flexes under braking and cornering. Developing a cracked windshield during the event could cause you to loose your tech approval and take you off the track.

Item eleven - SAFETY EQUIPMENT. Seat belt condition - no frying of the belt webbing, no stiff area, i.e., the belts are in good condition. The seat belt mounting must be secure, a loose seat belt mount is the same as no seat belt. You must have the same belt system for both the driver and instructor be it 3 point or more. Not fair to have a 5 point belt for the driver and expect the instruct to hang on with a 3 point belt. In this same avenue, the seat design should be the same for both the driver and instructor. If you have nice after market high tech seat for the driver, the instructor’s seat should be the same. You don’t need the instructor siding over and into you during a hard corner.

Item twelve - SAFETY EQUIPMENT - PERSONAL. You need at least an M85 rated helmet or better open or closed faced. If you have an open car you need a visor (both the driver and instructor!). As stated in the last article, long pants and long sleeved shirts for both the driver and instructor. Shoes above the ankles (that’s what the rules say-wear leather shoes)..

Going over the check list for the car reveals that the car is in good and safe operating mechanical condition. The requirements are higher that a state highway safety check and they should be. The requirements are basically the same for any car that is entered in an autocross.

From my experience as a racer, I noticed that you will be received better in the tech inspection if the car is neat and clean. This makes the tech inspector’s life easier as well as more efficient.

So you have the time to go over your car and have any problems corrected before the event. The better prepared the car, the less you have to work on it, the more time you have to concentrate on the driving event - makes sense to me. As a general rule, figure on having the brake system flushed, high performance brake pads installed, and a wheel alignment performed. Change the engine oil and filter, check the belts, hoses, and spark plugs, i.e. general preventive maintenance.

The very last item on the list to get ready for the PDX if you are a novice student is the student. As Chief Instructor, I will set-up the days schedule to maximize the on track time. To make life easier I suggest that you read AND UNDERSTAND one of the many driving books on the market. Four of the books are: Principles of Race Driving by Ayrton Senna, Competition Driving by Alan Prost, Driving in Competition by Alan Johnson, and Sports Car and Competition Driving by Paul Frere. First off, a PDX is NOT a race or competition event. Why I recommend these books is that they all explain the correct procedure of entering and exiting a corner at speed. Finally enter the event early at www.motorsportsreg.com. See you at the event.

2010, June