Blow Off Valves

Choosing the Right Blow-Off Valve: Sound vs. Performance

A performance blow-off valve (BOV) or diverter valve (DV) is a critical component for any turbocharged engine. It protects your turbo from damaging compressor surge and can improve throttle response. The choice depends on the sound you want and, most importantly, your car's engine management system. This guide will help you choose correctly.

Step 1: Atmospheric vs. Recirculating — The Critical Choice

This is the most important decision you will make. Use our "Product type" filter to find the right type for your car:

• Atmospheric (VTA): Vents boost pressure to the atmosphere, creating the classic loud "pshhh" sound. Warning: On cars with a Mass Airflow (MAF) sensor, this can cause the engine to run rich between shifts, leading to stumbles or stalling. Best for cars with a MAP sensor or custom race tunes.
• Recirculating (Bypass/DV): Recirculates the air back into the intake system pre-turbo. This is the OEM-style operation, offering quiet performance and 100% compatibility with all engine management systems, including those with sensitive MAF sensors.
• Hybrid (Dual-Port): The best of both worlds. These valves recirculate a portion of the air and vent the rest to the atmosphere, offering a noticeable sound without the major issues of a full VTA valve on a MAF-equipped car.

Step 2: Vehicle-Specific Kit vs. Universal Valve

Your choice depends on your project's complexity: