GFB Deceptor Pro II T9500 Diverter Valve

The GFB Deceptor Pro II T9500 Diverter Valve is a premium electronic boost control solution designed for Subaru WRX, STi, B4 Legacy, and Forester GT/XT models (MY99–04).

It combines OEM-style integration with full in-cabin control of blow-off valve sound, allowing drivers to adjust venting bias from silent recirculation to full atmosphere venting — or anywhere in between — on the fly.

Built on GFB’s proven DV+ and Respons technology foundation, the Deceptor Pro II delivers sharp throttle response, improved boost recovery, and full ECU compatibility without sacrificing reliability.

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⚙️ Key Features

• In-cabin electronic control of BOV sound (silent → loud)
• Adjustable venting bias (recirc / 50:50 / full atmosphere)
• Retains factory ECU solenoid for fast response
• Direct bolt-on replacement for factory diverter valve
• Compact design for tight Subaru engine bays
• High-torque electric motor control system
• Precision sealed internal gear drive mechanism
• Revised porting for improved airflow efficiency
• Plug-and-play wiring kit included

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🏁 Performance Benefits

⚡ On-the-Fly Sound Control
Adjust blow-off volume instantly from inside the cabin depending on driving style.

🚀 Faster Boost Recovery
Maintains boost pressure more effectively during gear changes, improving acceleration response.

🔒 Improved Boost Stability
Reduces factory valve leakage and inconsistent boost behaviour under load.

🎯 Sharper Throttle Response
Progressive valve control eliminates the abrupt open/close behaviour of OEM valves.

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🔬 How the Deceptor Pro II Works

The system builds on GFB’s electronic venting bias technology:

• Factory ECU and solenoid remain in control
• Electronic motor adjusts venting bias position
• Driver selects desired sound level via in-cabin controller
• Valve responds proportionally rather than binary open/close

👉 Result: precise control over airflow release without sacrificing drivability or ECU safety strategies.

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🔊 Sound Modes

🔇 Silent Mode (Full Recirc)
OEM-style operation with no external venting

🔊 Balanced Mode (50/50)
Mix of performance response and audible blow-off

📢 Full Atmosphere Mode
Maximum blow-off sound with aggressive venting character

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🚗 Vehicle Applications

• Subaru WRX MY99–00 (GC8 / GF / GC chassis)
• Subaru STi MY99–00 (GFC / GC8)
• Subaru B4 Legacy EJ20TT (BE/BH/BT MY98–03)
• Subaru GT / Forester GT MY98–00 (SF chassis)
• Subaru Forester XT / GT MY01–04 (SF / SG early models)

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🔩 Specifications

• Product Type: Electronic diverter / blow-off valve
• Control System: In-cabin proportional adjustment
• Technology: GFB Deceptor Pro II venting system
• Fitment: Direct bolt-on OEM replacement
• Material: CNC-machined alloy internal components
• Operation: ECU-controlled with electric adjustment motor
• Configuration: Recirc / 50:50 / Atmosphere adjustable

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🛠️ Installation Notes

• Direct replacement for factory diverter valve
• Uses factory ECU and solenoid system
• Includes wiring harness and in-cabin controller
• No ECU tuning required
• Designed for OEM mounting points

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💡 Why Choose the Deceptor Pro II?

If you want:

• Full control of blow-off sound from inside the cabin
• OEM drivability with aftermarket performance feel
• A premium alternative to fixed recirc or fixed atmo valves

👉 The Deceptor Pro II delivers adjustable sound without compromising boost performance or reliability.

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🏆 Perfect For

• Subaru turbo street and performance builds
• Drivers wanting adjustable BOV sound
• Daily-driven turbo vehicles needing OEM reliability
• Enthusiasts wanting both stealth and aggression in one system