If cars like yours typically suffer issues such as backfiring and stalling when using a fixed-ratio atmosphere-venting BOV, the Respons can help. By adjusting the venting bias to suit the car you can achieve a blow-off sound without having to put up with the issues. Like all GFB valves, the Respons utilises GFB's proven TMS Technology to ensure rapid boost recovery on gearshift and optimum throttle response, as well as the ability to withstand boost pressures of 100psi+. Put simply, it can hold more boost than any turbo could produce.. GFB's Respons, allowing you to infinitely vary how much air is recirculated or vented to atmosphere. Simply by twisting the adjustment ring, you can change the sound of your BOV from silent to ear-shattering!?.. Patented Venting Bias Adjustment Sysem-Can be Infinitely Adjusted between Full Recirc (silent) and full atmosphere (loud). Change the venting bias simply by twisting the adjustment ring.. Subaru WRX/STi MY99-00, B4 Legacy, GT/XT Forester MY98-04. GFB 99-00 WRX/STI TMS Respons Blow Off Valve Kit. Fully Adjustable sound BOV/Diverter. Turbocharger Blow Off Valve. GFB BOV/Diverter Valve. BOV/Diverter Valve

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