Forge Motorsport dump valve for BMW 135i

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.

Such a failure might not result in a check engine light being illuminated, as the valve can still be blown open by the boost pressure. This means that it isn’t always immediately apparent that the car is losing power through its OEM valve, with the diaphragm being prevented from sealing.

Forge’s alternative is a bespoke solution offering significantly improved reliability and the ability to work more efficiently on a tuned car. This valve is piston based, with no diaphragm to fail, and CNC hewn from a solid aluminium billet. It replaces the original unit with a pressure/vacuum operated piston valve that still also retains OEM ECU control over valve actuation.

This version is the ‘vent to atmosphere’ version which offers a distinctive ‘sneeze’ as excess boost is released. Both valves can be ordered in either polished or black anodised finishes, priced at £150.80 + VAT.