Vcds Logs are essential for understanding your car’s performance, especially if it’s tuned. This guide provides a step-by-step approach to performing basic performance logging with Ross-Tech VCDS software and interpreting the results.
Getting Started with VCDS Logging
Before diving into logging, ensure you have the following:
- Ross-Tech VCDS Cable: This cable connects your computer to the car’s OBDII port.
- VCDS Software: The software allows you to interact with your car’s control modules and record data. A Windows-based operating system is required.
- OBDII Port: Located under the dash on the driver’s side.
Step 1: Connect and Launch
Plug the VCDS cable into the OBDII port and turn your car to the “ON” position. Launch the VCDS software on your computer.
Step 2: Clear Fault Codes
Before logging, it’s crucial to clear any existing fault codes. In the VCDS main menu, click “Auto-Scan,” then “Start.” If faults are present, save the scan results and clear them using the “Clear all DTC’s” button. Return to the main menu.
Setting Up VCDS for Performance Logging
Step 3: Select Engine Module
Click “Select Control Module,” then “Select.” Choose “01-Engine” under the “Common” tab.
Step 4: Access Advanced Measuring Values
In the Engine Controller module, click “Adv. Meas. Values.”
Step 5: Record Ambient Air Pressure
Select and record the “Ambient Air Pressure” value. This is essential for later boost calculations. Uncheck the box after recording.
Step 6: Select Logging Parameters
Choose the parameters you want to log. VCDS allows a maximum of 12 parameters without grouping, or 10 with grouping. Prioritize the most relevant parameters for your logging session. Recommended parameters for general performance logging include:
- For B8/B8.5 Platforms: Accelerator position, Charge air pressure specified value, Engine speed, Air mass, Ignition angle (actual), Intake air temperature, Intake manifold pressure (absolute), Knock detection/correction (IGA_AD_KNK/IGA_AD_1_KNK_x), and Bypass valve (RFP_AV). Refer to the original article for specific group numbers for each parameter.
Step 7: Save Your Parameter List
Save the selected parameters for future use by clicking the “VCDS” icon and naming the file appropriately (e.g., “performance”).
Initiating and Capturing the VCDS Log
Step 8: Enable Turbo Mode and Grouping
Critically, enable “Turbo” mode and check “Group UDS requests.” This ensures faster logging and synchronizes timestamps for all parameters.
Step 9: Start Logging
With the car running, press “Log,” then “Start” to begin recording data.
Step 10: Conduct Your Logging Run
Perform your logging run in a safe, controlled environment. Capture a full 3rd or 4th gear pull from approximately 3000 RPM to 7000 RPM. Ensure consistent conditions for accurate comparisons.
Step 11: Stop and Save
Press “Stop” to end logging and “Done, close” to save the data as a .CSV file in the Ross-Tech/VCDS/Logs folder.
Conclusion
Successfully capturing a VCDS log is the first step. The next involves analyzing the data to understand your car’s performance. Remember to refer to the original article for additional logging parameters related to misfires, lambda values, fuel pressures, and more. Analyzing these parameters provides valuable insights into the health and performance of your vehicle. You can open the saved .CSV file with spreadsheet software like Microsoft Excel for analysis.
