Syllabus for teaching a zero time me to be competent in a high downforce/horsepower car.
Start with the loose nut behind the wheel-
I am focusing my approach as if I were teaching myself before I had any experience with a high downforce high horsepower car. For me, this would have been my transition from the two liter Chevron B36 sports racer into the Cosworth Spice.
How you approach this task has a lot to do with how you think. My right foot is connected directly to my brain and my primary interest is in being competent in things I do and not representing a threat to myself or others as I perfect skills. If this description fits you then perhaps the following sections will be of use.
Cold Tires
I have written about this in other sections of this site but I simply can not over emphasize the difficulty of dealing with cold tires. Everyone that I know of that has stepped into an Indy/ChampCar has gone around on cold tires. I took out a rear wing and rim at my very first race in an IndyCar. I was coming down the hill at Atlanta on pole and just lightly touched the throttle. The next thing I knew, I was facing everyone behind me and trying to figure out how to turn the wheel so I could continue to spin to the inside of the track (poll is on the inside so that was the nearest and safest place to head). I also spun at Mid-Ohio over that little jump on the far side of the track in the Shell car. That cost me a wing.
It is not just amateurs that do this. Pros from A to Z go around on a regular basis and they have the benefit of huge burnouts leaving the pits to get a little rear tire temperature. The Z is probably most etched in my mind as it cut short a brilliant career. It is simple; your tires will be cold leaving the pits so this is the first thing you will have to deal with.
The type of car will dramatically affect this problem. I started dealing with tires in the 300 hp sports racer on bias ply tires. The next step was the high torque Chevy Spice which has downforce but is also relatively lightly sprung in comparison to an Indy/ChampCar and thus has a ton more mechanical grip and a lot more feedback on cold tires. The last step was the Indy/ChampCar which, even using the third springs for ride height control, is very heavily sprung and has little mechanical grip when set up for relatively high speed road courses like Road America or Watkins Glen.
I would take me to a track with one or more slow corners (45-65 mph) where there are low curbs and lots of paved run off. I would set the car up with a fairly low rear ride height so there would be a lot of feel from the rear in slow speed corner entry with tire temperature. The car would not be so willing to rotate on these corners and would instead tend to push on entry. I would put some laps on the car to get tire temperature up then send student me out to get a feel for the car. Student me would not push the car hard enough to keep tire temp in the corners so I would insist on heavy acceleration leaving the corners once the car is completely straight. I would have student me run as many laps as it took to get comfortable in the car with instructor me getting tire temp at the start of each session. Once student me had enough situational awareness to tell me about the gages and was consistent on acceleration and general lap time I would move to the cold tire problem.
I feel that, if you are going to do it, you might as well get it over with in a safe place. The basic concept for getting past cold tires is to accelerate hard in a straight line until the car can take full throttle in second gear without breaking loose. At this point the rears have grip and you can begin to lean on them in the corners. So, I would have this talk as best I could with student me then send the student out on cold tires and ask him to push a bit around those corners with run off trying to lightly step the rear out and catch it. Again, if you are going to go around on cold tires, it is best to do so when you are by yourself and in a place where you will not damage the car. I would continue this exercise until the student could accelerate hard on corner exit with the car straight and was leaning on the car in the corners to the point of push. In other words, until the student could reliably get past cold rears and start pushing the fronts to put heat in them.
Once beyond cold tires, I would use the same test session to slowly add rear ride height until the student told me the car was a hand full on corner entry. Rear ride height is one of the best tuning tools for slow speed corner entry and a good solid rear here is the corner stone of confidence for the higher speed stuff. There is no better way to learn this than to experience it first hand and to do so in the same relative vicinity of the cold tire exercise so you can distinguish between the two.
Ok, now student me can get in the car and get rear tire temperature without looping it. I also can get front tire temperature by slowly driving through the huge understeer the follows when you have warmed the rears but have yet to warm the fronts. Burnouts behind the pace car helps in getting rear tire temperature but I have never had success get front temperature with the hard stops that follow.
Aero Lull
The next sizable difference on a high downforce car is the concept of aero lull. Most sensible drivers will not go balls out into a corner in an unknown car; you will slowly build speed until you find your own comfort or skill limits. This will work for most corners in a high downforce car but not all. If the car is set up right (correct downforce levels), there will be some corners where you will need significant speed to generate the necessary grip to make it through at that speed. Put differently, it is a catch 22. You need the speed to get the grip and without the speed there is not enough grip to keep you from flying off the road (or at least being very uncomfortable).
Turn one at Road Atlanta is such a corner for me. Bob Akin was kind enough to pull me aside and chat with me after watching me run my Cosworth Spice for the first time. He told me I looked good coming down the hill but could carry a lot more speed through one. My response was that I slowly built speed into one until the car started to loosen up a bit just like I had done in my Chevron. That car would drift until the little bit of camber near the apex would catch it then you could feed throttle up the hill. Bob’s response was to brake much earlier then go back to the throttle to balance the car before turning in. Do this lap after lap and slowly add more speed on turn in. He was right and not worrying about transitioning from the brakes to corner entry (braking earlier) allowed for a very smooth turn in which made it easier to carry just a bit more speed each lap. By the time I finished the next session, I was carrying fifteen more mile per hour through one and was back to coming off the brakes just as I turned in. I was braking later as I did not need to brake as much and was not braking as hard so the car was more stable on turn in. In fact, the car was hooked up turning in and had more speed in it than I had nerve to explore at that time.
Working through aero lull also allows the student to deal with much more life threatening or breath taking events with more confidence. A good example of this is the kink at Road America. I was running the BRIC one year and a friend was running the real 1999 Rahal Shell car. This guy can drive circles around me and yet was flying off the track in the brake zones (more about that later) and still running three seconds a lap slower than me. I got together with his crew chief and started to compare his Pi data against my Motec data. Sure enough, he was as fast or faster than I was on almost every part of the track which was no surprise given we were carrying about the same level of downforce. The one place were we differed was entering the kink. I was turning in almost fifteen miles an hour faster and, as a result, I reached terminal velocity much earlier than he did on the way to Canada corner. There were all three of the seconds!
I started off doing exactly the same thing as my friend at the kink. I would come out of the carousel approaching the kink then brake, downshift and accelerate through the kink. If set up right, these cars feel the best under acceleration. Once I got used to the track, I dialed in some aero under steer thus making so I had to wait on the nose all the way through the carousel. The wheel would start to go light when the front started to push and I would just stay shy of that push with a slightly light wheel until I could release the wheel on exit and apply power. This assured me that the car had aero push within a hundred yards of the kink. I then slowly increased my speed through the kink without braking of any kind. The goal was to go through faster and faster until the wheel started to lighten up indicating the onset of understeer. As speed picked up, I felt a bit of aero lull but never felt the front start to push. Sure enough, I got to the point where I could get to the throttle as fast as I dare exiting the carousel, click up two gears and go through the kink flat. It was everything I could do to wedge myself in the cockpit and turn the wheel. When done, I was routinely going through the kink at 172 mph apex speed and four g’s lateral loading. This compares favorably to some Moreno data I had from PKV showing the pros going through at 176 mph.
Once you have felt aero lull and have driven through it, you will gain a feel for it, be able to distinguish it from push or over steer, and be able to manage it at an unknown track. I would take student me to a track with a reasonable aero corner in the 110 to 125 mph range with no braking zone before it and good run off if possible. I would then dial downforce out of the car until it exhibited aero lull in this corner then do as Bob did with me and walk student me through the feeling. It is not a hard concept to come to grips with; you just need the right corner and set up to learn about it in a controlled environment. Once you have it nailed, it becomes a lot easier to deal with bloody fast aero corners.
The last issue I would want to cover with student me is braking. This is not so much life threatening as it is silly expensive.
You can literally stand on the brake pedal with all your might at 190 mph and you will not lock up the wheels at first. You will be thrown against your belts and that puppy will decelerate hard. However, if you keep that brake force, you will bleed off speed very quickly and soon reach the point where you are asking more of the brakes than the combination of tire and downforce will allow. The result is lockup and typically sliding off the road. The place where most people get caught out is that the car decelerates so fast at first then you let off the pedal and, even though the car is still slowing dramatically by “normal” standards, you feel like you are crawling up to turn in. Your instinct next time around is to hold off that little bit longer which delays your pulling off the pedal (the corner is still rushing at you) and then you lock up and flat spot $1800 worth of tires. Remember that expensive comment? My buddy took out four sets of tires at Road America that year! The key to keeping from looking like a nubie in the run off area and keeping your tire bill under control is to brake hard slightly early then learn how to bleed off pedal pressure as you bleed off speed or threshold braking for aero cars. Again, this mostly affects lap time and tire budget. Of course, once you have a feel for it, you will quickly be able to tell when someone dive bombing you on the inside will take themselves right off the track and you will know not to turn to prevent joining them in their accident.
The only other thing I would concentrate on with student me is simply getting time in the car. At first, these things are so overwhelming that you will be lucky to concentrate on what is directly in front of you. Over time your vision will expand to what is around the car and then to the gages and an ability to understand temperatures and pressures. It is simply a matter of time and this time is best spent away from events where you are on the track with much slower and much faster cars.