Perrin Recirculating Blow Off Valve (BOV) / Bypass Valve (BPV) for 2021 Subaru WRX STI

CARB Compliance / Exemption Warning: If you live in California and your application for this product is not CARB Compliant / Exempt, then you cannot purchase it for public highway or street use (in that case it could only be used for formally sanctioned race use on a racing vehicle that may never be used on a public highway or street). If your application is not CARB Compliant / Exempt and you're shipping to California, our system will let you know on the final checkout page.

These valves are designed to be recirculating. They can be vented to atmosphere, but will require a custom non-MAF tune and modification of the return line.

Also known as a Bypass Valve (BPV) or a Diverter Valve (if mounted on the turbo housing), the Perrin Recirculating Blow Off Valve allows you to have the sound and performance you love about a vent to air BOV while keeping the driveability and economy of a recirculating BOV. A bypass valve is an important piece of any turbo system. When you begin to increase boost or increase power to the engine, the stock valve begins to stress.

Key Features:

• Construction: The valve cap, piston and flange of the Perrin Performance Blow off valve are all CNC machined from 6061 billet aluminum. The Body is machined from a single block of aluminum. Without any additional bolt on or riveted pieces, potential leaks are eliminated and reliability is maintained.
• Adjustable Relief Pressure: The Perrin performance BOV features an adjustable cap which allows you to tailor when the BOV will open. Set it loose for a smooth release of boost at light loads and RPM. Tightened up, the BOV will release boost only at higher loads and RPM. This feature is independent of relief volume.
• Adjustable Relief Volume: The Unique design of the Perrin BOV allows you to adjust the volume of air released when the valve opens. This adjustment is independent of the relief pressure adjustment. Fine tune this adjustment to maximize throttle response and turbo longevity!
• Maintenance: Although it requires very little, the Perrin BOV is easy and quick to disassemble for cleaning without the need for special tools.
• 5 Year Warranty: Perrin Performance offers the original purchaser a 60 month warranty on this part!