Data acquisition devices have gone from being an exotic piece of technology in drag racing, to something that nearly any racer can have in their vehicle. The Davis Technologies Vehicle Position Sensor (VPS) is a unique data acquisition device that can measure many different variables and even produce a virtual timeslip. In this article, we take a look at how you can fine-tune the virtual time slip function of the VPS.

The VPS houses multiple sensors that gather data on several different things that happen during a run. You can look at the pitch, roll, and yaw of your vehicle as it makes a pass. This data is sampled at a very high-frequency level, so it’s very accurate thanks to the G-meter inside the VPS. You can use the VPS for wheelie control since it has the ability to communicate with your vehicle’s ECU and pull timing to prevent a potentially disastrous wheelstand. We’ve covered the VPS and all of its functions in detail, and you can see that article right here.

The virtual timeslip function of the VPS is an amazing tool that racers can use to keep track of each pass. The VPS will calculate velocity multiplied by time through its sensors to provide your elapsed time to a certain distance, with incredible accuracy. This function is very useful to have if there’s ever a timing system error, or you leave before the tree is activated. Thanks to the virtual timeslip function, you won’t have another wasted run without a timeslip again.

Shannon Davis, owner of Davis Technologies explains how you can fine-tune your VPS timeslip.

“The Rollout adjustment mostly affects the 60-foot calculation, and the calibration function mostly affects the e.t. and MPH. If the 60-foot is close and the e.t. and MPH are slow, then you’ll need to increase the calibration value,” Davis says. ‘First, with the VPS removed from the mount, rotate the housing so that the front of the housing is pointed straight up at 90 degrees to the earth. Next, go to the Live Display screen and note the Accel X value. It should read very close to 1.000 G.”

Davis explains what you need to adjust to finish the process.

“Now, if the value is low, such as .973, then the calibration value should be increased; if it’s higher than 1.000, then decrease the value. You’ll need to press the test button on the VPS to exit the Live Display screen and go to Settings>VTS Settings>Calibration. When you’re on this screen, change the value by 1000 points and save, then return to the Live Display screen and check the result. Finally, repeat the process as necessary to get the Accel X value as close to 1.000 as possible when the front of the VPS is pointed up. It is normal for the value to ‘dance’ a few points, a value of +/- 5-10 points of 1.000 should provide accurate results.”

You can learn more about the VPS and all of its functions right here on the Davis Technologies website.