Forge Motorsport has released details of its latest dump valve (or blow-off valve) for all BMW 135 Turbo models that have the electronically controlled bypass valves fitted. The product was engineered to solve a problem that can occur on tuned models with increased boost pressure. Forge calls it a “useful ‘belt and braces’ measure” for any car running hard in a warmer climate. Failure of the stock valve can happen under either set of circumstances.