Set of 4 Forge Motorsport adjustment springs for pop-off valve – Ø 35 mm

Reference: FO-FMDVTUN

Supplier Ref.: FMDVTUN

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The Forge Motorsport 4-spring adjustment kit (35 mm diameter) for pop-off valves allows you to adapt the operation of a compatible valve to the configuration of the turbocharged engine. Its four stiffness levels let you adjust the valve’s behavior, particularly after a change in boost pressure.

A spring that is too soft can cause the valve to open improperly and result in a drop in pressure. Conversely, a spring that is too stiff may prevent the valve from opening when necessary. Mounting a stiffer spring does not, by itself, increase turbo pressure; it can only correct a drop caused by an unsuitable spring.

The choice of spring depends on the valve used and the engine configuration. The pressure ranges listed are selection guidelines, not guaranteed opening thresholds for all mountings. An excessively stiff setting can disrupt valve operation and damage the turbocharger.

Dump valves compatible with the Forge Motorsport FMDVTUN spring kit

FMDV20
FMDV22
FMDVM2LA
FMDVRMR
FMDV500A
FMDV18
FMDVHFTFSI
FMDVEVO14
FMDV001GTI
FMDV004
FMDV12VAG
FMWRX301
FMDV13R

Other kits and mounting restrictions

FMDVR60A: Use the FMTVTUN spring kit.
FMDVST180R: Use the FMTVTUN spring kit.
Forge dual-piston pop-off valve for Smart Roadster: The FMDVTUN kit is compatible with the main supercharging spring. The small idle spring requires the FMTVTUN kit.
DVR and DV007 diaphragm valves: Do not use the red spring from the FMDVTUN kit.
FMFSITV and FMDVSPLTR: Not compatible with this kit.

Before ordering: verify the exact part number of the pop-off valve and the sizes of the installed spring. Compatibility depends on the specific pop-off valve installed, not just the vehicle model.

Technical Specifications of the Forge Motorsport Pop-Off Valve Springs Kit

Brand: Forge Motorsport.
Manufacturer part number: FMDVTUN.
Function: Adjustment of compatible pop-off valve springs.
Packaging: Set of 4 springs.
Approximate diameter: about 35 mm.
Approximate height: approximately 39 mm.
Green spring: 5 to 15 PSI, or approximately 0.35 to 1.03 bar.
Yellow spring: 15 to 23 PSI, or approximately 1.03 to 1.59 bar.
Blue spring: 23 to 30 PSI, or approximately 1.59 to 2.07 bar.
Red spring: 30 PSI and above, or approximately 2.07 bar and above.
Order of increasing stiffness: green, yellow, blue, red.
Identification: The colors correspond to the stiffness codes; the appearance of the springs shipped may vary.

Key Features of the Forge Motorsport Spring Kit for Pop-Off Valves

Four stiffness levels to adjust valve operation.
Adjust the setting after changes to the engine configuration.
Replace the spring without having to replace the entire compatible pop-off valve assembly.

Products intended for vehicle modification for competition purposes may render their use prohibited on public roads, insofar as they significantly alter the vehicle's characteristics as specified in the type-approval certificate issued by the relevant authorities (noise level, pollutant emissions, maximum speed, tire dimensions, etc.).