Variable Valve Timing (VVT-2): A Comprehensive Guide for DIY Enthusiasts

Variable Valve Timing (VVT-2) is a sophisticated engine technology that optimizes power, torque, and fuel efficiency across a wide range of engine speeds. By varying the timing of the intake and exhaust valves, VVT-2 systems can improve combustion efficiency, reduce harmful emissions, and increase power output. This comprehensive guide will delve into the technical details of VVT-2, providing DIY enthusiasts with a deep understanding of this advanced engine technology.

Understanding VVT-2 Valve Timing Adjustment

One of the critical aspects of VVT-2 is the degree of valve timing advance or retard. These systems can vary the valve timing by up to 15 degrees or more, depending on the engine speed and load. This variability allows the engine to optimize its performance across a wide range of operating conditions.

The degree of valve timing adjustment is controlled by the VVT actuator, which uses oil pressure to move a cam phaser. According to a study by Yuan et al. (2018), the oil pressure required to operate the VVT actuator can range from 0.2 MPa at low engine speeds to 0.5 MPa at high engine speeds. Maintaining the correct oil pressure is crucial for the proper functioning of the VVT-2 system.

Measuring VVT-2 Performance

variable valve timing vvt 2

The VVT-2 system’s impact on engine performance can be quantified through several key metrics:

  1. Valve Timing Advance/Retard Degree: The degree of valve timing adjustment, which can range from 0 to 15 degrees or more, depending on the engine and VVT-2 system design.
  2. Oil Pressure: The oil pressure required to operate the VVT actuator, which can vary from 0.2 MPa at low engine speeds to 0.5 MPa at high engine speeds.
  3. Fuel Efficiency: Studies have shown that VVT-2 systems can improve engine fuel efficiency by up to 10% compared to fixed valve timing systems (Fu et al., 2018).
  4. Power and Torque Output: The VVT-2 system’s ability to optimize valve timing can lead to increased power and torque output, particularly at higher engine speeds.

VVT-2 Maintenance and Troubleshooting

Proper maintenance is crucial for the long-term performance and reliability of the VVT-2 system. Here are some key maintenance tasks:

  1. Engine Oil and Filter Changes: Regularly change the engine oil and filter, following the manufacturer’s recommended maintenance schedule. The VVT-2 system requires a sufficient supply of clean oil to operate correctly.
  2. Electrical Connection Inspection: Ensure that the VVT-2 system’s electrical connections and wiring are in good condition and free from corrosion or damage.
  3. VVT Actuator Inspection: Periodically inspect the VVT actuator for signs of wear or damage, and replace it if necessary.
  4. Diagnostic Trouble Code (DTC) Monitoring: Monitor the engine’s diagnostic trouble codes for any VVT-2 system-related issues, and address them promptly.

Advanced VVT-2 Tuning and Optimization

For DIY enthusiasts looking to extract the maximum performance from their VVT-2-equipped engines, there are several advanced tuning and optimization techniques:

  1. VVT Timing Tables: Utilize VVT timing tables, which provide detailed information on the optimal valve timing for different engine speeds and loads. These tables can be found in resources like the HP Tuners Bulletin Board.
  2. VVT Actuator Pressure Optimization: Experiment with different oil pressure settings for the VVT actuator to find the optimal balance between power, torque, and fuel efficiency.
  3. Integrated VVT-EGR Tuning: For engines with both VVT-2 and Exhaust Gas Recirculation (EGR) systems, optimize the integration of these technologies to further improve performance and emissions.

By understanding the technical details of VVT-2 and following best practices for maintenance and optimization, DIY enthusiasts can unlock the full potential of this advanced engine technology and enjoy the benefits of improved power, torque, and fuel efficiency.


  • How Variable Valve Timing Works – YouTube (2017-11-09). Retrieved from
  • VVT Tables – HP Tuners Bulletin Board (n.d.). Retrieved from
  • Yuan, Z., Fu, J., Liu, Q., Ma, Y., & Zhan, Z. (2018). Quantitative study on influence factors of power performance of variable valve timing (VVT) engines and correction of its governing equation. Energy, 159, 788-800. doi: 10.1016/
  • Variable Valve Timing (VVT) (n.d.). Retrieved from
  • Application to a GDI Engine with Variable Valve Timing and EGR (2018). Retrieved from
  • Fu, J., Liu, J., Feng, R., Wang, Y., Yang, J., & Wang, L. (2018). Energy and exergy analysis on gasoline engine based on mapping characteristics of speed and load. Energy Conversion and Management, 78, 46-57. doi: 10.1016/j.enconman.2013.10.035