Kinugawa Big Head Adjustable Internal Wastegate Actuator — Single & Dual Port, 2-in-1 Integrated Spring

The Kinugawa Big Head Adjustable Wastegate Actuator is a direct-fit, bolt-on upgrade engineered to solve one of the most common boost control failures in turbocharged engines: premature wastegate opening under high boost. The factory actuator's weak diaphragm spring allows the wastegate to blow open before target boost is reached, robbing mid-range torque and limiting peak power. Kinugawa's enlarged diaphragm head and precision-wound integrated spring hold the wastegate closed longer — delivering quicker spool, sharper throttle response, and sustained peak boost.

Available in boost pressure ratings from 3 PSI to 26 PSI, this actuator features a 2-in-1 integrated spring design that makes it compatible with both single-port and dual-port wastegate configurations without modification.

Why Upgrade to the Kinugawa Big Head Actuator?

• Enlarged diaphragm area increases spring pressure and wastegate hold force
• Keeps the wastegate valve seated longer for higher peak boost achieved sooner
• Produces strong torque from idle through the entire RPM range
• Crisp, controlled boost response — eliminates boost creep and mid-range sag
• 2-in-1 integrated spring: single and dual port exchangeable in one unit
• Adjustable rod length with 2mm preload for precise installation fit

Single Port vs. Dual Port — What's the Difference?

Single Port Actuators
Boost reference is supplied to one side of the diaphragm. The wastegate opens in one direction; spring pressure alone handles the return stroke and holds the wastegate closed. Best suited for basic boost control via a manual boost controller (MBC) or electronic boost controller (EBC). Simple plumbing, straightforward setup — ideal for street and mild performance builds.

Dual Port Actuators
Boost reference is supplied to both sides of the diaphragm, enabling bidirectional control of the wastegate — both opening and closing. Spring pressure is pneumatically assisted on the return stroke, allowing a softer spring to achieve the same or higher boost targets with greater precision. Recommended for high-boost applications, high exhaust backpressure environments, or oversized wastegates. Best used with an EBC for maximum tunability.

Tech Tip: Dual port actuators can also be run as a traditional single port — simply leave the lower actuator port vented to atmosphere. This makes the Kinugawa 2-in-1 design a future-proof choice for any build.

Integrated Spring Pressure Reference

Spring configurations: 3 PSI inner / 7 PSI inner / 7 PSI middle / 11 PSI middle / 10 PSI outer / 7 PSI outer. Select your target boost pressure from the variant selector above.

Installation Notes

• Designed for internal wastegate turbochargers
• Apply 2mm of preload to the actuator rod during installation
• For clevis-type applications: set 2mm preload on the wastegate valve arm, then verify with compressed air at a pressure slightly above the actuator's rated spring pressure
• Spring surface paint is used for color identification only — it does not affect spring function or performance

Kit Contents

• 1 × Kinugawa Big Head Dual-Port Adjustable Wastegate Actuator Head
• 1 × Installation Instruction Sheet (download PDF)

Product Details

• Brand: Kinugawa Turbo Systems
• Condition: Brand New
• Port Type: Single & Dual Port (2-in-1 Integrated)
• Boost Pressure Range: 3 PSI – 26 PSI (select variant)
• Country of Origin: Taiwan
• HS Code: 841191
• Weight: 1 kg