A Guide to Using Live Time slip and Time slip Rate.
Live time slip is a comparison between the lap you are currently driving, with the fastest lap of the current session. This can be setup to be displayed using the shiftlights of a DASH4PRO or DASH2 PRO display.
The time slip calculations are performed by the data logger so this feature is only available with DASH2 PRO + GPS data logging option, DL1 MK3/CLUB/PRO/WP or VIDEO4+GPS units.
Methods to display time slip variables
Using the shiftlights as a performance indicator provides an easily interpreted display: red for slower (bad), green for faster (good) with the amount of red/green lights showing the degree of time lost or gained. The shiftlights can also be configured to illustrate time slip values in seconds.
All time slip variables can also be configured to be displayed as numerical values on a display screen. The advantage of using a time slip variable over for instance lap or sector delta or predictive lap time is that it is updated continuously, not just at lap/sector markers, giving the information sooner and allowing more time to improve on any losses.
There are 2 main time slip variables, time slip [s] and time slip rate [%].
• Time Slip [s]
is a measure of time lost/gained, where this loss/gain occurs, and is shown in seconds. Time slip is measured over the course of a lap or sector, so the value (time in seconds) is resultant of all losses and gains prior to the current value.
• Time Slip rate [%] is a comparison of speed in relation to track position, and effectively highlights where on the circuit time is being lost and gained. Time slip rate is measured at a specific track position so is not compounded by previous losses and gains in time.
Using Time Slip Rate:
Time slip rate is used in the DASH4PRO’s performance indicator (also available on DASH2 PRO), where the LED scale is used to indicate time slip rate compared to the fastest lap or theoretical fastest lap (combined fastest sectors). Using the performance indicator a driver can expect to push the limits of braking zones, improve racing lines, and improve consistency in lap times.
When setting up the DASH4PRO’s shiftlights, there is an option to set them up “as a performance indicator”. The LED scale displays from -15% to +15%. Time slip rate is about how much time you are loosing and gaining at the current point on the track, and does not indicate how much time you are already up or down. So a driver will see green lights for later and harder braking than before, as well as faster cornering, even if they got stuck behind a slower vehicle at the beginning of a straight (where they saw red lights). This makes it ideal for learning how to drive a particular track, even on a busy practice session.
Using a single lap marker will give time slip rate in comparison to the fastest lap. Using both lap and sector markers will combine the fastest sectors to create the fastest theoretical lap for time slip rate comparison.
Using Time Slip [Seconds]:
During a race it can be preferable to display time slip in seconds, allowing the driver to gauge the overall time performance continuously throughout the race. Using this setup, drivers can expect to benefit from consistent and faster lap times. There are 3 different ways to setup the time slip [s] display and understanding how time slip works is important in order to get the data you require. The data logger performs the time slip calculations. It knows the length of your fastest lap and the time it took to drive every part of it. So a time slip comparison is against the distance into the lap driven and the time it has taken to get to that distance. So should the route taken around the track change significantly (e.g. cutting a corner or coming off the track) then the time slip comparison will become inaccurate until the lap/sector marker is crossed again and the time slip comparison will reset.
Option 1 – Time Slip [s] per lap
So with the most basic lap file, just a lap marker, you will get a continuous time slip around the whole track, with the time slip comparison resetting at the lap marker. As explained above, the downside of this is that should the line taken around the track vary significantly (and the distance of the lap increase/decrease) then the accuracy of the measurement will deteriorate throughout the lap. At average racing speeds a distance error of +/-5m will only account for around 0.1-0.2 of a second, so for most users this is not a major issue.
Option 2 – Time Slip [s] per sector
With a lap file including both lap and sector markers the time slip comparison will be against the fastest sectors in the current session. So at each sector marker the timeslip comparison will reset, increasing the accuracy of the measurement (as total distance driven will vary less over the shorter distance of each sector, than a whole lap) but not giving a comparison against the entire lap. The timeslip shown on the display will indicate the time lost/gained against the fastest that particular sector has been driven. Each sector marker will cause the timeslip indicator to reset to 0 with no LED’s lit. So as well as giving increased accuracy to the timeslip measurement this also means the comparison is against the fastest theoretical lap time, made up of the fastest sectors in the whole session. However this option doe not give an overall time slip on the whole lap time.
Option 3 – Time slip [s] per lap with sector updates
A third option is to create “user defined variables” that perform live calculations on the data. If we add “time slip [s]” to “best lap delta [s]” so VAR_0040+VAR_7007.
This would combine the time difference between the sector’s time slip (the lap file must include both lap and sector markers) and the overall lap time’s comparison to the fastest at that point. “Time slip [s]” is updated continuously, and “best lap delta” is updated at the sector markers. This method achieves a continuous time slip comparison against the whole lap time, with sector markers adjusting the time slip’s accuracy, but not resetting it to 0. The result is an increased accuracy time slip giving continuous comparisons to the entire lap time.
In order to display this “user defined variable” on the LEDs the sign must be switched to conform to the green = good, red = bad convention. To do this another “user defined variable” must be created, with the equation: 0-(VAR_6001). VAR_6001 = User variable 1, if another variable has been used for the time slip calculation then update accordingly.
Use this second user defined variable to “display a barchart based on a variable” in the “Setup shiftlights” menu of the DASH4PRO configuration.