GFB 99-21 Subaru WRX STI WGA Wastegate Actuator (Tune Required)

Go Fast Bits is known for making well-built performance parts that offer a noticeable difference. This internal wastegate actuator is designed to give your Subaru Impreza's turbocharger more control over boost pressure. If you're looking to get more out of your turbo, especially after making other modifications, this part can help achieve faster spool-up and more consistent boost levels.

What sets this actuator apart is its unique diaphragm design, which uses a bead retention system to achieve a large effective area in a compact package. This means it has more authority over the wastegate flap, leading to better boost control. It also features an exceptionally long stroke, up to 18mm of rod travel, which is great for controlling larger wastegates or for increasing boost pressure without needing to change springs. The rod guide is made from PEEK, a high-performance polymer, offering low friction and excellent wear resistance while keeping the overall height down. This attention to detail results in one of the shortest actuators available on the market.

Adjusting the base spring pressure is crucial for performance, and GFB made this easy. The actuator comes with three stainless steel springs that can be combined for pressures ranging from 5psi to 22psi. But instead of just offering spring options, GFB included an industry-first turnbuckle adjustment. This allows you to fine-tune your base boost pressure in minutes without swapping springs or removing the actuator, thanks to its long stroke providing a wide adjustment range. Keep in mind that installing this part requires a tune to properly manage the increased boost capabilities.