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

E1 External Discharge Valve (ES1)

The development of this new product originated not only from the demand for a high-performance racing solution, but from addressing a well-known issue with the factory-installed valve used in all T-Jet engines of the Abarth, Fiat, Alfa Romeo, and Lancia group.
The original membrane valve is unable to withstand the high pressure and temperature peaks required under demanding conditions, often leading to membrane failure and a significant reduction in engine performance, particularly during acceleration and at maximum load.
Even when the original membrane remains intact, performance issues can arise when turbine pressures increase — for example, following ECU remapping.

To overcome these limitations, we developed the E1 External Discharge Valve (ES1), designed for enthusiasts seeking maximum performance and a distinctive sound characteristic. The external venting system enhances turbo response while producing an unmistakable, sporty discharge noise.

Key Features:

• No membrane – replaced with a high-performance thermoplastic thermopolymer piston designed to withstand extreme temperatures (over 270 °C), ensuring absolute reliability and durability.

• High-efficiency solenoid with reduced power consumption and 20% faster opening and closing times compared to OEM valves.

• Tested and guaranteed operation up to 3 bar with inlet air temperatures up to 170 °C.

• Precision-machined automotive-grade aluminum body, anodized for durability and corrosion resistance, with minimal lead content.

• 360° rotatable mounting bracket for flexible and optimized installation.

• IP67-rated watertight connector and solenoid body for complete environmental protection.

• OEM-style black finish, maintaining a discreet appearance within the engine bay.

• Fully plug-and-play installation, compatible both mechanically and electronically, allowing straightforward fitting by professional installers or experienced users.

• Switchable for open or closed with sound adjustment.

The E1 External Discharge Valve (ES1) delivers superior reliability, faster response, and the aggressive sound profile desired by performance enthusiasts — a true upgrade over the original design.