Forge Motorsport K04 turbocharger actuator for Audi S3 8P/SEAT Leon II/Škoda Octavia II

Replacement turbocharger actuator for vehicles based on the MK5 Golf chassis with a 2.0 FSi engine.

Forge Motorsport has developed a two-piece replacement aluminium actuator with a machined housing for turbochargers. This version enables more precise adjustment and control of the required boost pressure, which can improve boost system response and regulation.

• Choice of spring rate according to the vehicle
• Made from 6026-grade aluminium
• Version adapted to the specific vehicle
• Version adapted to the specific turbocharger
• Made to order
• Piston or diaphragm operation available for most actuators
• Diaphragms made from Nomex-reinforced fluorosilicone
• Laser-cut stainless steel brackets where required
• Adjustment and service kits are available
• Made in England

Spring adjustment

The actuator is supplied assembled with a standard spring. The basic spring is suitable for standard or slightly increased boost pressure. For modified vehicles, a stronger spring can be used where higher boost pressure is required.

Diaphragm sealing of the internal components is the standard version, while piston sealing is also available. The piston version provides comparable operation and requires less maintenance due to the durable design of the piston internals.

The actuator is designed to increase the output boost pressure of the turbocharger system. Compatibility is not guaranteed for all versions, and the engine management system, whether factory or upgraded, may not allow the pressure to be increased beyond its set parameters.

All actuator rods are made from 303-grade stainless steel.

The stated spring pressures according to the colour markings apply only to the mechanical part and are mainly relevant to older turbocharged engines that are not controlled by an ECU or solenoid valve. In modern engines with ECU or solenoid valve control, the target boost pressure should not be directly equated with the mechanical spring specification. When selecting a spring for a specific model and planned level of modification, follow the recommendations of a qualified tuner.

For the T2 spring range, the designation FMAS049 applies.

Kit contents

• 1 × FMACVAG06 actuator
• 1 × Forge sticker

If you want to use the FMPACTUN spring adjustment kit, the Type 2, 049 diaphragm version must be selected.

Suitable for: Audi S3 II (8P), SEAT Leon II (1P1), Škoda Octavia II (1Z3).

Compatible vehicles (manufacturer data)

Before ordering, check that the product matches your vehicle (model, year and engine). If in doubt, write to us — we will check for you.