What is "Time Slip" and "Time Slip Rate"? What does it mean and how is it calculated?
Time slip and time slip rate are 2 standard variables available within the Race Technology analysis software and alongside speed and lateral acceleration are probably the most useful for race analysis.
So you've logged data from your first race and you know that your second lap was the fastest at 47 seconds and your third lap was slower at 49 seconds, so the obvious question is where did you lose the 2 seconds? One way would be to simply generate a graph of the speeds on the 2 laps and compare them - however a simpler way is to use "time slip" or "Time slip rate"- basically it is a way of comparing where you were faster and slower for 2 laps.
"Time slip" or "Time slip rate" are 2 variables that essentially describe the same thing - which one you use is entirely the user's choice. Both variables present exactly the same information, just in a different way - so there is no advantage of using one compared with the other. It really depends on which you find easier to understand and which seems more logical to you.
"Time slip rate" is the easiest to understand, simply it is a comparison of the speed on the 2 laps. Continuing the example above, if on the second (the fastest) lap you were doing 50mph on a particular section of the track, and on the third lap you were doing 40mph on exactly the same place then you would be slower than the fast lap by 20%, so the "time slip rate" would be 20%. If you look at time slip rate around a particular part of the track then the higher the value, then the slower you were going relative to your best lap.
It is also worth mentioning that it is entirely possible that for some parts of the lap you may have been going faster than your best lap, although overall you went slower. Taking the same example again, for the second (fastest) lap you may have been going 50mph, but on the third lap you were doing 52mph at the same point. In this case the "Time slip rate" is about -4%.
"Time slip" is basically the sum of all the "time slip rates", so for example if "Time slip rate" is a constant 20% for the first 10 seconds of the lap, then "time slip" would be (10 seconds *20%) 2 seconds. At the end of the lap the "Time Slip" is equal to the difference in the lap times of the 2 laps. You can think of "Time Slip" like a predictive lap time. For example if you are quarter of the way around the lap and the "Time Slip" is 2 seconds and from then on you drive exactly as you did for you best lap then your eventual lap time will be exactly 2 seconds slower than your best lap time.
The final point is that both "time slip" and "time slip rate" are both calculated by comparing the current lap with the "best theoretical lap". Click here for more information on the Best Theoretical Lap.