Set of 4 small Forge Motorsport pop-off valve springs – Ø 20 mm

The Forge Motorsport kit of 4 small adjustment springs (20 mm diameter) for pop-off valves allows you to adapt the operation of compatible valves to their specific application. It includes four levels of stiffness to adjust the setting based on the valve part number and engine configuration.

The springs are identified by the codes green, yellow, blue, and red, from softest to firmest. They correspond to an approximate increase in stiffness of 25%, 50%, 75%, and 100%, respectively, compared to the original spring. These percentages do not represent an increase in boost pressure or a gain in power.

On compatible twin-piston asprated dump valves, the FMTVTUN kit can be used in conjunction with the FMDVTUN kit: each corresponds to a separate spring. For the Forge twin-piston pop-off valve on the Smart Roadster, the FMTVTUN kit applies only to the small idle spring.

Dump valves compatible with the Forge Motorsport FMTVTUN spring kit

• FMDVR60A
• FMDVST180R
• FMDVCS14A: main supercharging spring.
• FMDVK04D
• FMDVK04S
• FMDV33A
• FMDV33R
• FMDV38
• FMDVA1TSI
• FMDVDS3A
• FMDVMK7R
• Forge dual-piston pop-off valve for Smart Roadster: small idle spring only.

Dump valves requiring the FMDVTUN spring kit

The following part numbers use the FMDVTUN kit for the relevant spring, not the FMTVTUN kit shown here:

• FMDV20
• FMDV22
• FMDVM2LA
• FMDVRMR
• FMDV500A
• FMDV18
• FMDVHFTFSI
• FMDVEVO14
• FMDV001GTI
• FMDV004: main spring.
• FMDV12VAG
• FMWRX301
• FMDV13R
• FMDV21
• FMDV39
• FMDV008
• Forge dual-piston pop-off valve for Smart Roadster: main supercharging spring.

Mounting Restrictions and Precautions

• FMDVSPLTR: Requires its specific spring; the FMTVTUN kit is not compatible.
• FMEDV106A: Not compatible with this kit.
• DVR and DV007 diaphragm valves: The prohibition on using the red spring applies to the FMDVTUN kit; it does not constitute confirmation of compatibility with the FMTVTUN.

Before ordering: verify the exact part number of the pop-off valve, the function of the spring to be replaced, and its sizes. The choice of color must take into account the valve-specific recommendations and the engine configuration. The pressure ranges for the FMDVTUN kit must not be applied to the FMTVTUN kit.

Warning: An unsuitable spring may disrupt valve operation and damage the engine or its associated components.

Technical Specifications of the Forge Motorsport Small Spring Kit for Pop-Off Valve

• Brand: Forge Motorsport.
• Manufacturer Part Number: FMTVTUN.
• Function: Spring adjustment for a compatible pop-off valve.
• Packaging: set of 4 small springs.
• Approximate diameter: 20 mm.
• Approximate height: 25 mm.
• Green spring: approximate 25% increase in stiffness.
• Yellow spring: approximate 50% truss increase.
• Blue spring: approximate 75% increase in tension.
• Red spring: indicative truss reinforcement of 100%.
• Basis for comparison: spring from the original mounting, depending on the application.
• Order of increasing stiffness: green, yellow, blue, red.
• Identification: color-coded; the appearance of the springs delivered may vary.

Key features of the Forge Motorsport small spring kit for pop-off valves

• Four stiffness levels to adjust the valve setting.
• Pop-off valve springs replacement.
• Can be used to complete the FMDVTUN kit on certain dual-piston mountings.