Shock Velocity

Shock velocity channels can help in suspension tuning, by showing the rate of change in inches per second. The following procedure illustrates how to create math channels in the DataLink II software to show the shock velocity for each shock travel sensor.

In order to add these channels, open the file in which you wish to add them. If it is a run file, simply open it from the ‘File’ menu in the DataLink II software. If you wish to add it to your configuration file, so the channel will appear in all subsequent downloaded files, select ‘Open Car Configuration’ from the ‘File’ menu, and select the appropriate configuration file from the available list.

Once the desired file has been opened in the software, select the ‘Channel Maintenance’ option under the ‘Edit’ menu.

Click on the channel in the list where you would like to insert the new channel. Typically, we add the velocity channels after each of the shock travel sensors installed on the system. In this example, we are going to add shock velocity to the right rear shock travel, so we will click on the channel immediately following ‘RR Shock Pos’. Click on ‘Easy Insert Channel’.

Now we need to select the type of channel we will be inserting. Since we are looking at rate of change, we will need to select ‘Derivative’ and under the Type, we will select expression (EXPR). Click ‘OK’.

Click on the text box beside Name and enter the desired name. Since we are adding a velocity channel for the right-rear shock, we will use ‘RR Shock Vel’. Then click in the Expr: text box and then scroll down through the list until you find the channel called ‘RR Shock Pos’. Double-click on it so that it appears in the expression text box.

Leave the Smoothing Factor at ‘1’. Change the digits after the decimal point to ‘3’ and enter the Result Unit of ‘in/sec’. Be sure to scale the minimum and maximum values correctly for your application. We recommend the minimum value of ‘-50’ and ‘50’ as the maximum.

Click ‘OK’ to add the channel to the list, and then repeat the process to add any additional shock velocity channels to the remaining shock sensors on the system (LR Shock Pos, RF Shock Pos, LF Shock Pos).

Once you have finished adding the desired channels, click ‘OK’ to return to the main screen of the DataLink II software. You should see the channel buttons ‘RR Shock Vel’ and any others you created appear in the location into which you inserted them. If you are satisfied with the results, be sure to click ‘Save’ from the ‘File’ menu.

For questions or assistance in adding these channels to your system, please contact us at Performance Data Systems at (949) 652-6300 or email us at