The 7 Best Blow off Valve for WRX Reviewed 2025

When I first started modifying my WRX, I quickly learned that the stock bypass valve (BPV) just couldn’t handle the higher boost I wanted, often leading to annoying compressor surge. Finding the right valve isn’t just about getting that satisfying psshhh sound; it’s crucial for protecting your turbo and maintaining consistent power. We’ve tested and compared some of the top options available today to help you find the best blow off valve for wrx, covering everything from high-flow recirculating valves to adjustable atmospheric setups designed for maximum performance and acoustics.

IMAGE	PRODUCT NAME	AMAZON LINK
	Blue Aluminum Dual Port Blow Off Valve (BOV) Dump Valve…	View on Amazon
	Aluminum Adjustable Blow Off Valve Kit for 2002-2007 Subaru…	View on Amazon
	Car Blow Off Valve Spacer Fit For Sub-aru For Impreza…	View on Amazon
	14471AA143 Air Bypass Blow Off Valve Fit For Impreza For…	View on Amazon
	Angle Flange Blow Off Valve For Subaru 02-07 IMPREZA WRX…	View on Amazon
	Recirculating Bypass Valve BPV for WRX STI 2004+, CNC…	View on Amazon
	Subaru Genuine Intercooler & Blow off Y-Pipe Gaskets…	View on Amazon

Blue Aluminum Dual Port Blow Off Valve (BOV) Dump Valve for Mazdaspeed 3 (2007-2013), Mazdaspeed 6 (2005-2007), CX-7 (2006-2012), Subaru WRX (2008-2014), Forester XT (2008-2012)

This dual-port BOV is a popular choice for older generation WRX owners (2008-2014) looking for a reliable valve that delivers both sound and function. Featuring a 50/50 dual port design, it vents half the air to the atmosphere for sound and half back into the intake for smoother idle, balancing performance with acoustics. Constructed from premium aluminum, this valve provides outstanding durability and corrosion resistance, ensuring it stands up to high-pressure turbo applications without failure. The sleek blue finish also provides a visual pop under the hood.

Key features that stand out:
– Design: 50/50 dual port operation (vents some air for sound, recirculates some for smoother running)
– Material: High-quality aluminum construction for exceptional longevity
– Compatibility: Wide fitment range including 2008-2014 WRX models

Pros:
– Provides the desirable BOV sound without excessive stalling or running rich.
– Excellent build quality designed to hold higher boost than stock.
– Complete installation kit included (gasket and blind cap).

Cons:
– Professional installation is highly recommended as instructions are not included.

Best for: 2008-2014 WRX owners who want noticeable sound and improved boost control.

Expert Opinion: This 50/50 design is often the safest bet for street-driven WRXs, minimizing the common issues associated with full atmospheric BOVs while still providing great acoustics.

Aluminum Adjustable Blow Off Valve Kit for 2002-2007 Subaru WRX, 2004-2017 STI – Boost Control, Turbo Protection

Designed specifically for the earlier WRX and STI platforms, this adjustable blow off valve kit focuses heavily on performance enhancement and boost control. Its key advantage is the fully customizable air volume control, allowing the user to fine-tune the amount of air vented, preventing damaging compressor surge during high boost shifts. Made from high-grade aluminum, this valve is built to last and ensures your turbo is protected, even when running aggressive tunes.

Key features that stand out:
– Adjustability: Independent control over air volume release and relief pressure
– Protection: Larger outlet helps eliminate compressor surge effectively
– Quality: 100% brand-new, high-grade aluminum construction

Pros:
– Allows for precise tuning to match specific boost levels and driving styles.
– Specifically engineered for older WRX/STI generations (02-07 WRX, 04-17 STI).
– Helps maintain optimal turbo function and response.

Cons:
– Adjusting the valve can take time to perfectly dial in performance.

Best for: Enthusiasts with modded 2002-2007 WRX models needing meticulous boost control.

Expert Opinion: If you are running high boost on an older EJ platform, the ability to independently control both volume and pressure relief is crucial for maximizing efficiency and preventing pre-detonation.

Car Blow Off Valve Spacer Fit For Sub-aru For Impreza for WRX STi 2015-2020 Air Bypass Blow Off Valve, Replacement Part Number 14471AA143 14471-AA143

This product isn’t a traditional aftermarket BOV; it’s an OEM-style replacement air bypass valve spacer for the newer 2015-2020 WRX and STI models. Constructed from sturdy, high-grade metal, this piece is far more durable than the plastic components sometimes found in stock applications. While it won’t give you the loud “whoosh” of an atmospheric valve, it ensures reliable OEM performance and provides a sleek silver aesthetic enhancement to the engine bay. This is ideal for fixing leaks or ensuring a robust seal.

Key features that stand out:
– Material: Sturdy, deformation-resistant metal materials
– Installation: Engineered for easy, hassle-free replacement installation
– Fitment: Direct OE replacement for part number 14471AA143 (2015-2020)

Pros:
– Exceptional durability compared to potential stock plastic parts.
– Maintains factory reliability and ECU settings.
– Very easy and quick to install.

Cons:
– This is a functional replacement, not a performance sound upgrade.

Best for: 2015-2020 WRX/STI owners needing a reliable OEM replacement component.

Expert Opinion: For modern WRXs (VA chassis), maintaining the recirculating function is often best for overall drivability due to the sensitive MAF sensor. This heavy-duty metal replacement guarantees long-term stock functionality.

14471AA143 Air Bypass Blow Off Valve Fit For Impreza For WRX For STi 2015-2020, Metal Intercooler By Pass BOV Valve Replacement, Replaces 14471-AA143

Similar to the previous item, this is another robust, metal-constructed direct replacement for the OEM bypass valve on the 2015-2020 WRX/STI. Built from high-strength metal, its primary function is to resist wear and deformation under repeated pressure cycling, ensuring the bypass system functions optimally for the life of the vehicle. If you are experiencing minor boost leak issues related to the stock plastic component failing, this is an excellent, durable solution.

Key features that stand out:
– Durability: Constructed from high-strength metal to resist deformation
– Aesthetics: Sleek, modern silver finish that improves engine bay appearance
– Fitment: Designed to perfectly match OEM specifications for 2015-2020 models

Pros:
– Ensures reliable, long-lasting factory boost holding.
– Direct bolt-on replacement requires no tuning adjustments.
– Highly resistant to wear and heat cycling.

Cons:
– Performance benefits are limited to improving reliability of the stock system.

Best for: Owners focused purely on OEM reliability and durability for their 2015+ WRX.

Expert Opinion: While not strictly an aftermarket upgrade, ensuring the integrity of your bypass valve with a strong metal replacement like this is essential maintenance for any modded WRX.

Angle Flange Blow Off Valve For Subaru 02-07 IMPREZA WRX STI SQV SSQV HKS BOV

If your main goal is that classic, aggressive blow off valve sound, this angle flange BOV (often modeled after the popular HKS Super SQV) is designed to deliver. It is specifically compatible with the classic 2002-2007 WRX/STI models (EJ20 and EJ25 platforms). This is a purely atmospheric venting valve, releasing all pressure to the environment, resulting in a very sharp, noticeable sound every time you lift off the throttle.

Key features that stand out:
– Sound Profile: Aggressive atmospheric venting for maximum acoustic impact
– Compatibility: Direct fitment for 2002-2007 WRX/STI and 2008-2012 STI
– Style: Classic angle flange design

Pros:
– Delivers the loudest, most recognizable blow off sound.
– Simple design suitable for many EJ platforms.
– Affordable entry point for atmospheric venting.

Cons:
– Full atmospheric venting can cause the car to run slightly rich (stutter/hesitation) between shifts.

Best for: Older WRX/STI owners whose priority is the signature BOV sound.

Expert Opinion: While fantastic for sound, full atmospheric valves on MAF-based systems like the WRX often require minor ECU tuning to truly maximize performance and eliminate minor hesitation between gears.

Recirculating Bypass Valve BPV for WRX STI 2004+, CNC Billet Aluminum High-Flow OEM Replacement (Red)

This Recirculating Bypass Valve (BPV) is arguably the best blow off valve for wrx owners prioritizing maximum performance without sacrificing OEM drivability. Crafted from aircraft-grade billet aluminum and featuring an internal brass piston, this high-flow unit is pressure tested to over 70 PSI—far exceeding stock limitations. Because it is 100% recirculating, it maintains factory ECU programming, meaning no tuning is required and you avoid running rich issues.

Key features that stand out:
– Design: 100% Recirculating (BPV) for optimal drivability
– Construction: CNC machined billet aluminum with internal brass piston
– Flow: Higher flow and larger cross-section than the stock unit, capable of holding 70+ PSI

Pros:
– Direct bolt-on fitment, requiring zero tuning or permanent modifications.
– Guarantees reliability at extremely high boost levels.
– Maintains smooth idle and fuel economy of the stock BPV.

Cons:
– Does not produce the loud atmospheric BOV sound.

Best for: High-boost WRX/STI builds where reliability, driveability, and maximum boost holding capability are essential.

Expert Opinion: If you are running an aggressive stage 2+ tune or larger turbo, this high-flow BPV is functionally superior to most atmospheric BOVs, as it holds boost better and is less stressful on the engine’s fueling map.

Subaru Genuine Intercooler & Blow off Y-Pipe Gaskets 2002-2005 WRX 2004-2018 STi Set of 3 OEM

While not a blow off valve itself, this set of Genuine Subaru OEM gaskets is critical when installing or servicing any new WRX BOV or BPV. Boost leaks are a common source of reduced performance, and worn-out gaskets are often the culprit. This kit provides the necessary intercooler Y-pipe gaskets and the specific blow off valve gasket (21896AA072) required to ensure a perfect, leak-free seal on many WRX and STi models. Using genuine OEM parts ensures the fitment and material quality are exactly as the factory intended.

Key features that stand out:
– OEM Quality: Genuine Subaru parts guarantee perfect fitment and material integrity
– Coverage: Includes gaskets for both the intercooler Y-pipe and the blow off valve
– Prevention: Essential for preventing boost leaks when installing a new valve

Pros:
– Required for ensuring a proper seal when swapping the BOV.
– Eliminates boost leaks caused by old, cracked gaskets.
– Compatible with a wide range of EJ WRX/STI years.

Cons:
– Must be purchased in addition to the BOV itself.

Best for: Anyone performing maintenance or installing a new blow off valve/bypass valve who needs reliable sealing hardware.

Expert Opinion: Never reuse old gaskets, especially around pressurized components. This small investment ensures that the performance gains from your new valve aren’t lost through leaky seals.

Comparison Insights: Recirculating vs. Atmospheric

When looking for the best blow off valve for wrx, the biggest decision is whether to go Atmospheric (BOV) or Recirculating (BPV).

The Recirculating Bypass Valves (BPVs), like the high-flow Recirculating Bypass Valve (Product 6), are generally better for performance and drivability on WRX models. Since the WRX uses a Mass Air Flow (MAF) sensor, venting air to the atmosphere confuses the ECU, which expects that air to return to the intake. Recirculating designs maintain proper airflow readings, ensuring smoother shifts and consistent idling.

Conversely, the Atmospheric BOVs (like Products 1, 2, and 5) deliver the much-desired loud, aggressive turbo sound. While they provide the acoustics enthusiasts crave, they often require more tuning effort to prevent the engine from briefly running rich or hesitating when shifting, particularly on mild tunes. The 50/50 dual port (Product 1) is a good compromise, providing sound while minimizing ECU confusion.

Products 3, 4, and 7 are essential OEM replacement/support parts, focusing entirely on reliability and maintenance rather than performance sound.

Final Verdict

Choosing the best blow off valve for wrx depends entirely on your goals: sound or reliability.

For the Highest Performance and Reliability on a heavily tuned car (Stage 2+): The Recirculating Bypass Valve BPV (Product 6) is the clear winner. It will hold massive amounts of boost without requiring tuning adjustments, protecting your engine.

For the Best Balance of Sound and Performance (Recommended for most daily drivers): The Blue Aluminum Dual Port Blow Off Valve (Product 1) offers the iconic sound while maintaining enough recirculation to keep the ECU happy.

For the Classic Aggressive Sound: If you drive an older WRX and prioritize the loudest acoustics, the Angle Flange Blow Off Valve (Product 5) is the traditional choice, but be prepared for potential tuning needs.

Frequently Asked Questions About Best Blow Off Valve for WRX

What is the difference between a Blow Off Valve (BOV) and a Bypass Valve (BPV)?

A Blow Off Valve (BOV) vents excess air pressure directly to the atmosphere, which creates the loud “whoosh” sound. A Bypass Valve (BPV) is a recirculating valve that vents the excess air pressure back into the vehicle’s intake system, maintaining the factory fuel/air ratio. For most modern Subarus, a BPV is recommended to avoid issues with the MAF sensor.

Do I need to tune my WRX after installing an aftermarket blow off valve?

It depends on the valve type. If you install a 100% atmospheric BOV, tuning is often required. Since the WRX’s MAF sensor measures air before it’s dumped, the ECU is expecting that air to return. Dumping it causes the engine to run momentarily rich, which can cause stalling, hesitation, or rough idling. If you install a recirculating BPV, tuning is generally not required.

Will installing a new blow off valve increase horsepower?

No, a blow off valve itself does not directly increase peak horsepower. Its function is to rapidly relieve pressure when the throttle closes, which protects the turbocharger from compressor surge and keeps the turbo spooled more efficiently between shifts. The benefit is felt in turbo protection, reliability, and quicker spool-up response, not raw peak power gains.

Does a blow off valve affect the WRX’s Mass Air Flow (MAF) sensor?

Yes, full atmospheric BOVs can disrupt the MAF sensor readings. The MAF reads the air mass before it enters the turbo. If a BOV vents that metered air to the atmosphere instead of recirculating it, the ECU calculates too much fuel for the air remaining, resulting in a rich condition and poor drivability.

Is it legal to have an atmospheric blow off valve on my WRX?

The legality of atmospheric blow off valves often depends on local emissions standards and regulations. In many regions, venting metered air to the atmosphere is considered modifying the factory emissions system, making it technically illegal for street use. Always check your local and state laws regarding emissions compliance.

What causes “compressor surge,” and how does a new BOV help prevent it?

Compressor surge occurs when the throttle plate suddenly closes (like during a shift), and the rapidly pressurized air has nowhere to go. This air slams backward against the spinning turbo compressor wheel, causing a stuttering noise and putting massive stress on the turbo shaft and bearings. A properly functioning or upgraded blow off valve opens quickly to release this pressure, protecting the turbo from damage.