DRIVING INFO

AUTOCROSS DRIVING

THE FOLLOWING WAS DONE SEVERAL YEARS AGO FOR THE COMPUSERVE AUTO FORUM

Written By David English III

Hello All,

Here's the Final draft put together with additional input provided by David Pozzi, Don Elzinga, John Panuzzo.(Experience in Racing and Autocross)

SLALOM RACING(normally speeds under 80kms through cones)

A. {CAR PREPARATION}

1. -- Absolutely a must would be wheels in balance & alignment!(Note that alignment is important but if you use a separate set of tires for racing balance isn't' overly important), Brakes in working order!!, restraints depending on your class.

2. -- the suspension needs to be in top condition, especially wheel bearings, ball joints, bushings and steering linkage. These parts have heavy loads placed on them and need to be in good condition to keep the tires flat on the pavement. I would consider improving tires and shocks and suspension (in that order) to be the most important items for improving times.

[You might want to have your rear axle flanges magna-fluxed every few years. I've seen a few come unglued. It can really mess up your calipers and brackets if you've got rear disk brakes.]

3. -- Increase your tire pressure, especially on the older models, to prevent/minimize 'tire roll', I used to run my BF Goodrichs at 44 psi when Slaloming and 35psi on the street.

[Tire pressure should be set for the best: F/R traction I.E. Braking, Acceleration. (slightly lower pressure helps.) cornering power, (slightly higher pressure helps) mainly keep the sidewall from rolling over. driver feel (higher helps.) even temperature across the tread is an indication you are close. you can feel the tire with your hand immediately after a run. Run about 5 to 8 pounds more air pressure in the front tires. The front tires have more side force on them because the front tires do about 75 percent of the work of keeping the car from leaning in a corner. They also are being turned and braked (75 percent of braking too!) when entering corners and that is when you are likely to roll the sidewall under if the pressures are to low. 40 to 45 psi is a good front pressure. The rear tires have less side load and weight in a corvette. Although I think the weight bias is close to 50-50% at least they used to be in the old ones. The slightly lower pressure in the rear will help acceleration traction by giving a larger footprint. if you go too low the center of the tire will not press down and any advantage will be lost.)]

4. -- Try to get as much negative camber and positive caster in the front as you can get.

[Up to a point. Some cars can get too much camber (I don't know about 'vettes). If you go past 2 degrees, braking starts to suffer.] NOTE: there's a much larger explanation on this factor but due to the length of this message it won't fit, it's included in the file UL.

5. -- Run with a full tank of gas.

6. -- Tires: Proper Road Race or autocross dot (us department of transportation street legal) radials will be about 5 seconds quicker in a 1 minute run. Compared to the kind you would buy in a regular tire store. Competition between the tire companies has been so fierce that these tires are sometimes better than racing slicks for autocross use. use rims as wide as the tread width.[Note that in stock class, you're restricted to a rim size that was available on your car.]

7. -- a warmer tire is almost always better for traction.

B. {COURSE PREPARATION/INSPECTION}

1. -- Always good to walk the course, memorize the course in your head and run through it in your head.

2. -- While walking the course, look for a "line", the path you believe will be the fastest(not necessarily the shortest) in particular try to pick out trouble spots, braking areas, downshift areas, etc.[I can't stress enough the fact that the driver needs to know exactly where the car needs to be all the way thru the course.]

3. -- Take a practice run, but don't race the course, put in a quick solid run to get a feel for the course and assess if your 'course inspection' was on or not. I like to put in a quick, smooth run to set as a bench mark and determine how much I can shave off it when I 'race' it<g>

[If the drivers first run is his fastest it is an indication of over driving. He should strive to make the last run his fastest. by building speed each run and improving specific areas where he remembers he had trouble on the last run. If the driver is too aggressive he won't be able to recall where he needs to improve on his next run. He will also find that he needs to leave extra clearance from the cones to allow for the car sliding all over and will miss hitting his apexes more often.]

C. {RUNNING THE COURSE}

1. -- Hand position and Seat position! 9 and 3 or 10 and 2 depending on wheel size and comfort, for those of us with older model cars, good handwork is a must, a smooth and well positioned hand over hand is far more reliable than the palm "wax-on, wax-off" with tighter corners. You probably want to slide your seat forward a bit relative to where you would put it for relaxed cross-country driving. That gives you better leverage over the steering wheel.

2. -- Picking the proper gear to run in!!, Don't have experience with stds through the course but with a Late Model('89 in this case) 4 spd auto and 3:08 gears we ran very noticeably quicker times keeping it in first than 2nd(until the straight away finish of course). I run mine usually in 2nd with my 3:70s except for very slow and tight courses.

3. -- Load your car before you break the timing light. (Autos)Put your foot on the brake and Load(rev) the car until you near your stall limit, I've a 2500 stall convertor I normally bring it to 23-2400 before I take off, sometimes 2000 if I'm having trouble hooking up.

4. -- Sliding is slow! looks cool<g> but doesn't help on the clock(Weeelllll maybe in a 180 corner but you'd have to bring it quick and then straight with hookup right away, still its more flash than dash).

5. -- Tire squeal!, get used to it<g> especially pre '84s what with tire scrub you should be screaming around the track<g>.

6. -- look ahead, in skiing we were always told to look 3 gates ahead so I look 3 cones ahead<g>

7. -- be smooth and try and get a rythem, being jerky(not just steering but acceleration too) just causes more problems. A pyramid or cone style section is a good test for this.(starts with small left and rights and gets wider per each set of cones so your cranking around the middle and it becomes narrower again. don't see it much but it's cool.

8. -- A wheels traction patch; when you brake it becomes larger up front, smaller in the rear and when accelerating smaller up front and larger in the rear. So this being true, should you be working the brake and the accelerator through the corners? I prefer(and find more comfortable) keeping my revs high with a downshift and working the accelerator to increase front or rear traction.[Be aware that running a lower gear at high rpm will increase oversteer. Simply backing off the throttle will cause the car to wag its tail. Sometimes this can be an advantage, sometimes not. I would suggest balancing the suspension and sway bars for neutral handling in second gear and expect oversteer in first.]

9. -- Whatever you do don't trash your car!!<VBG> John brought up a good point on the serious side of the humor statement "Drive it Like you Hate it" This has merit, he knows of a guy who Drag Races to the motto and he wins often, I also know a guy who "Drives it to wreck it" and he wins often in Slaloms. Obviously you won't run as fast if your worried about 'hurting' your car but it's still a ton of fun and you get to push your car and get a better feel of how it'll react and handle when an emergency situation arises in everyday driving.

D. {BETWEEN RUNS}

1. -- I usually go to the little boys room<sg>, seriously though after a good run your pumped up on adrenaline(like drinking a pot of coffee<G>) it's best to take care of business now then get that 'feeling' when your buckling up for you run.

2. -- Between runs open the hood and cool the engine by idling until the engine reaches minimum temp then shut off. TPI engines make more power when cool. Go watch the other cars run, you can learn a lot by watching them.

Many thanks to those that participated in the discussion to put this together!

Greets from Canada

Dave English III (Corvette Club of Nova Scotia)

"Wave all you Vette Owners!"

350hp/700R4/3:70gears modified '81 Vette