Blitz BR Dump Valve - Blow Off Valve - 70647 - MR2 TurboBlitz BR Super Sound Blow Off Valve Release Type The striking new design in black red dissipates heat more effectively and the venturi shaped funnel creates a sharp dynamic sound. BR dump valves also feature "Dual Drive" for maximum response, a small port for low boost and a larger port for high boost. Manufactured from die cast CNC machined aluminium with a brass piston and a rubber diaphragm, meaning they can easily cope with boost pressures up to