Subaru WRX STI Wastegate Actuator - Go Fast Bits - WGA - `99-`21. A direct-fit high-performance internal wastegate actuator designed to improve boost control and tuning flexibility on WRX STI models from 1999–2021.

The GFB WGA replaces the factory actuator with a compact, higher-authority unit that offers finer control over the wastegate flap. Its industry-first Silicone/Nomex diaphragm with improved bead retention yields a larger effective area in a smaller outside diameter, giving more consistent boost control without added bulk. An 18mm rod stroke provides the longest travel in its class for controlling large internal wastegates or increasing base boost without spring changes. A machined PEEK pivoting rod guide reduces height, friction and wear, keeping the actuator compact and durable. The WGA ships with three stainless-steel springs adjustable between 5–22 psi in combinations, plus an intuitive turnbuckle for quick spring preload adjustments—so you can tune base boost pressure in minutes. Note: tuning may be required after installation.

Features

• Silicone/Nomex diaphragm with enhanced bead retention for greater effective area
• 18mm long rod stroke for extra travel and higher boost support
• PEEK pivoting rod guide for low friction and reduced height
• Three stainless springs (5–22 psi range) and turnbuckle preload adjustment
• Bolt-on fit for WRX STI `99–`21; universal options available from GFB

If you have questions or want to confirm fitment, call us directly — Austin, TX: 512-982-9393 (TX) or Los Angeles, CA area: 562-981-6800 (CA). We offer installation and customization services at both our Austin and Los Angeles locations. If you’re considering multiple items, contact us for possible shipping discounts. We install on premises at both locations.

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