Bonalume Switchable Atmospheric Dump Valve / BOV Blow Off Valve For Abarth T-Jet Engine

The Bonalume switchable Blow Off Valve (ES1) is a reliable and powerful replacement for the standard T-Jet valve. The original valve uses a thin membrane that often fails when boost or temperatures rise. As a result, many Abarth, Fiat, Alfa Romeo, and Lancia drivers notice power loss and slow throttle response, especially after a remap.

To solve this problem, the ES1 uses a strong piston system instead of a soft membrane. This design handles heat and pressure far better. It also creates a sharper and more aggressive discharge sound, which many drivers enjoy.

Why the OEM Valve Fails

The factory membrane valve cannot cope with high pressure or heat. During hard acceleration, the membrane can weaken or split. When this happens, the car loses boost and performance. Even if the membrane does not break, it often struggles once boost levels increase after tuning. Because of this, many tuned cars suffer from leaks and slow response.

How the ES1 Fixes These Issues

The E1 External Discharge Valve (ES1) is built to be strong, fast, and consistent. Its high-quality piston design offers smooth operation in both standard and tuned engines. Thanks to this upgrade, boost control remains stable even in extreme conditions.

Key Features

• No membrane – uses a high-temp piston made from a strong thermoplastic material.

• Fast solenoid – opens and closes up to 20% quicker than the OEM valve.

• Tested to 3 bar – safe with inlet temps up to 170 °C.

• CNC-machined aluminium body – anodised for strength and corrosion protection.

• 360° rotating bracket – makes installation simple and flexible.

• IP67 waterproof solenoid and connector – ideal for long-term reliability.

• OEM-style black finish – keeps the engine bay looking clean.

• Plug-and-play fitment – works with the car’s factory systems.

• Switchable operation – choose open or closed with adjustable sound.

Performance Benefits

The ES1 reacts faster than the stock valve, so turbo response improves straight away. It also prevents boost loss caused by membrane failure. This helps the engine stay safe and consistent under load. In addition, the external discharge setup gives the car a strong and sporty sound. Overall, the E1 External Discharge Valve (ES1) offers better durability, better response, and a more exciting driving experience.