Respons T9035 Diverter (35mm inlet, 30mm outlet – suits MY97-98 WRX/STi)

The GFB Respons T9035 Diverter Valve is a high-performance dual-port blow-off valve designed for early Subaru WRX and STi models (MY97–98) featuring a 35mm inlet and 30mm outlet configuration.

Unlike standard blow-off valves, the Respons incorporates GFB’s patented venting bias adjustment system, giving drivers precise control over how much air is recirculated versus vented to atmosphere — delivering both performance and sound control in one unit.

Built on GFB’s proven TMS (Turbo Management System) foundation, the Respons improves boost recovery, throttle response, and overall drivability while eliminating common BOV-related issues such as stalling or compressor surge.

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⚙️ Key Features

• Patented dual-port venting bias adjustment system
• Adjustable sound output (silent → 100% atmosphere)
• 35mm inlet / 30mm outlet configuration
• Direct bolt-on replacement for factory diverter valve
• Retains factory ECU solenoid control
• CNC-machined aluminium valve construction
• Precision internal piston design
• Fully adjustable venting control
• Designed for MAF-sensitive engines
• Manufactured in Australia (ISO 9001 quality system)

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🏁 Performance Benefits

⚡ Customisable Blow-Off Sound

Fine-tune venting bias to control exactly how loud or subtle your blow-off sound is — from OEM quiet to full atmosphere.

🚀 Faster Boost Recovery

Improves return-to-boost speed by up to 30% faster than factory diverter valves, enhancing shift response and acceleration feel.

🔒 Improved Drivability

Prevents stalling, backfiring, and unstable idle conditions commonly associated with full-atmosphere BOV setups.

🎯 Sharper Throttle Response

TMS-based operation reduces delay between throttle input and boost delivery, improving corner exit and gear change response.

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🔬 How the Respons System Works

The Respons uses a dual-port staged venting system:

• Recirc port opens first for stability
• Atmosphere port opens progressively based on adjustment setting
• Venting bias dial controls airflow split between ports
• ECU and factory solenoid remain fully in control

👉 Result: smooth, adjustable performance without compromising reliability or drivability.

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🔊 Venting Control Options

🔇 Full Recirculation Mode
OEM-style quiet operation with maximum stability

🔊 Hybrid Mode (50/50 adjustable)
Balanced performance with audible blow-off sound

📢 Full Atmosphere Mode
Maximum sound with aggressive venting character

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🚗 Vehicle Applications

• Subaru WRX MY97–98 (GC8 / GF chassis)
• Subaru STi MY94–98 (GC8)
• Subaru WRX Wagon MY97–98
• Subaru GT / early performance EJ20 turbo models
• Nissan SR20DET platforms (S13 180SX / Silvia)
• Nissan 300ZX Z32 VG30DETT
• Toyota Celica GT-Four ST185 / ST205
• Mazda 626 GT / F2 Turbo models
• Mitsubishi Starion 4G63 turbo models
• Holden Commodore VL RB30ET

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🔩 Specifications

• Product Type: Dual-port adjustable diverter valve
• Technology: GFB Respons TMS venting system
• Material: CNC-machined aluminium construction
• Fitment: Direct OEM replacement (selected turbo models)
• Control: Mechanical venting bias adjustment dial
• Operation: ECU-controlled solenoid retained
• Configuration: Recirc / Hybrid / Atmosphere adjustable

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🛠️ Installation Notes

• Direct replacement for factory diverter valve
• Uses OEM ECU and solenoid control system
• No tuning required for installation
• Adjustable via external venting bias control
• Designed for MAF-sensitive turbo engines

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💡 Why Choose the Respons T9035?

If you want:

• Adjustable blow-off sound without drivability issues
• Faster turbo response and improved shift recovery
• OEM reliability with performance tuning capability
• A proven dual-port system that prevents stalling

👉 The Respons delivers control, performance, and sound in one precision-engineered system.

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🏆 Perfect For

• Subaru turbo street and rally builds
• Drivers wanting adjustable BOV sound
• MAF-equipped turbo vehicles
• Performance upgrades with OEM drivability retained
• Enthusiasts wanting both performance and sound control