Turbo tuning parts > Miscellaneous parts | VW (Golf 4 1.8T GTI) | FMIPCV

If only there was a way to make the dump valves spring operation completely independent of the spring pressure inside. A way to allow its function to work perfectly at any boost level. , Forge’s technicians beavered away to find a solution. What they came up with is called the Intake Pressure Compensation Valve (or IPCV )… and it’s really rather clever.

What makes the IPCV valve ingenious is that it re-routes the various high and low pressure feeds through a clever internal piston system (see diagram). When the throttle is opened and the car is accelerating, boost pressure generated by the turbocharger will ensure that whichever dump valve or recirculation valve you have fitted will be kept sealed. As no boost is now being lost through the intercooler (which can usually be anywhere between 1-3 psi of boost drop) the pressure acting on top of the piston of your dump valve is precisely equal to that underneath it. The result? Only a relatively weak spring is required to keep it operating, which means response times can be kept quick and throttle response is immediate.

Fitting instructions

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