Forge Single Blow Off Valve and Hard Pipe Kit, Suits BMW 335i N54 Twin Turbo. A Forge Motorsport Blow-Off/Dump Valve is designed to be an upgrade to the factory valve. Capable of dealing with higher boost pressures, more reliably designed. Forge also offer the option of an atmospheric valve on many cars. Uprated for higher boost pressures. Replace failure prone factory valves. Option of atmospheric blow-off noise. When you come off the throttle on a turbocharged car the built up charge of pressurized air has to go somewhere. If it can’t, or if the air isn’t released quickly enough, then the turbo will slow down or even stall leading to a delay getting back on boost when you get back on the throttle. This is where a dump valve comes in. It releases the built up pressure. Most cars have a dump valve of some sort fitted from the factory. This will have been tuned for the factory tune and boost levels though. On many cars a soft flexible diaphragm is part of the valve and these wear out. Once the valve is leaking it can cause problems with how the engine functions. Forge Motorsport offer a wide range of uprated dump valves/blow-off valves. These are designed to handle additional boost. Each valve is designed to do a very thorough job of releasing pressure, getting your turbo back on boost fast. For some vehicles, Forge offer a choice of recirculating dump valves and atmospheric dump valves. A recirculating valve is what most cars come fitted with from factory. It discretely recirculates excess air back into the inlet. While there will be no extra noise, the valve will be compatible with increased boost pressure. An atmospheric valve, on the other hand, vents the built up pressure to atmosphere, giving that distinctive whoosh sound. Many modern engines have problems when you switch from recirculating to vent to atmosphere. Forge have, for selected vehicles, engineered a complete solution to try and get around this. This means you can enjoy the sporty blow-off valve noise on a wider range of cars than ever. For many of us that noise is all part of the fun a of a turbocharged car! Please carefully check the title to see what type of valve is selected. A recirculating valve will not make the distinctive blow-off valve noise. On vehicles where the valve is connected to the ECU (increasingly common on many modern engines), Forge are supplying a complete kit with relevant wiring and plugs. These are generally supplied with full instructions. Dynodaze Performance Parts Ltd Specialises in aftermarket parts and remapping. We have a Dyno Rolling Road and can provide all manner of work from simple servicing to engine conversions. We have an experienced mechanic and fabricator ready to fit any and all parts required. Additional to this we can provide full Health Checks to get your vehicle ready for remapping including Diagnostics and Smoke testing for Boost leaks. Unit A3 Greenwood Court.