Maximizing traction is crucial, especially at corner exits. Datalogging can easily be used to show how the car behaves tractionwise by just using the rpm and speed data. In a GPS enabled data logger a separate speed sensor is not even necessary, although it provides useful comparison data.
The image below shows a track map from Alastaro, with the location of the car shown by the circle. This is the corner exit prior to the main straight (start/finish line). Next to it on the right an rpm vs. speed chart shows the shift pattern of the car (data plotted over two consequtive laps). This type of chart is usually used to make sure the gear box ratios are set correctly.The chart below these shows rpm, speed and a software calculated variable called "speed over 1000 rpm". This variable is simply the ratio of speed divided by engine rpm, and is a constant for each gear (in fact, gear shifting patterns can easily be seen from the plot).
I have encircled the last part of this plot, where the crosshairs correspond to the data for where the car is (corner exit). If you look closely at the yellow line (speed over 1000rpm) you can see that the line is not straight as it should (corresponding to a constant value, namely that of the second gear) but rather has some fluctuations. These fluctuations are clearly below the constant line (that follows as the car picks up speed), indicating that at this point the rpm's are higher relative to the speed of the car than what they should be in second gear had the car full traction. Clearly then the driver is losing some traction at this place, or alternatively is deliberately "sliding" the car. Traction loss of course can be caused by careless throttle use, poor suspension setup, or worn tires for that matter.
To analyze this, I added further down some data on throttle position in that specific position on the track. As you can see, the driver quite smoothly applies the throttle, and the 100% throttle on position corresponds to the highest point on the yellow line, indicating he has improving traction there. However, the driver then maintains the throttle "to the floor", but traction falls off. It would be interesting to see his steering inputs at this position, but this is something that has to wait until we get a sensor for that!
All in all, ensuring good exit speed at this point of the track is quite important, and thus this area warrants further study as we seek to improve our laptimes further.
