Are you considering upgrading your turbocharged vehicle’s performance? Understanding the difference between a diverter valve and a blow off valve is crucial. This article delves into the mechanics of each, their respective benefits, and helps you determine the right choice for your car.
How a Diverter Valve Works
In a turbocharged engine, the throttle plate opens when you accelerate, allowing air to enter. The turbocharger compresses this air and forces it into the engine for increased power. When you shift gears and let off the throttle, the throttle plate closes. However, the turbo continues spinning. A diverter valve manages the pressurized air created by the still-spinning turbo. It recirculates this air back into the intake system, preventing it from causing the turbo to stall or spin backwards. This recirculation also allows the Mass Air Flow (MAF) sensor to accurately measure airflow for optimal fuel injection.
Conversely, a blow off valve releases the pressurized air into the atmosphere, creating a distinctive “whoosh” or “pshh” sound. While this sound is often desirable for car enthusiasts, venting the air can disrupt the engine’s air/fuel ratio, potentially leading to a richer fuel mixture and decreased performance in some vehicles.
Diverter Valve Benefits: Performance and Reliability
The factory-installed diverter valve in your Volkswagen or Audi plays a critical role in regulating turbocharger boost. It ensures smooth throttle response and prevents turbo lag. A malfunctioning or inadequate diverter valve can lead to boost leaks, sluggish performance, and extended turbo lag. Upgrading to an aftermarket diverter valve, especially for chipped or tuned engines, can improve reliability and performance by handling increased boost pressures more effectively.
Diverter Valve vs. Blow Off Valve: Key Differences
The core distinction lies in how each valve handles pressurized air. A diverter valve recirculates the air back into the intake system, maintaining a consistent airflow for the engine’s computer to manage. A blow off valve vents the air to the atmosphere, creating the characteristic “whoosh” sound but potentially causing issues with the engine’s air/fuel mixture and performance, particularly in vehicles with complex engine management systems. Choosing between the two depends on your performance goals and whether you prioritize smooth engine operation or the auditory satisfaction of a blow off valve’s sound. While blow off valves might seem appealing, they can trigger drivability problems or error codes in some sophisticated engine management systems found in certain Volkswagen and Audi models.
Diverter Valve Installation: An Example
Replacing a factory diverter valve, often a source of boost leaks, with a more reliable aftermarket option is a common upgrade. For instance, on a Volkswagen or Audi 1.8T engine, the electronically actuated diverter valve is typically located on the side of the turbocharger’s compressor housing, between the passenger-side fender well and firewall. Accessing it requires lifting the vehicle and removing three Allen bolts.
Choosing the Right Valve: Diverter or Blow Off?
Ultimately, the best choice depends on your specific needs and vehicle. If you seek improved performance and reliability without compromising your car’s engine management system, a diverter valve is the preferred option. If you desire the distinctive sound of a blow off valve, carefully consider your car’s engine management system and potential compatibility issues. Consult with a qualified mechanic or tuning specialist to determine the optimal solution for your vehicle. Upgrading to a performance diverter valve is often recommended for modified or tuned engines to handle increased boost pressures effectively.
