This Supplemental Positive Crankcase Ventilation Valve protects the crankcase from becoming pressurized at turbocharger boost conditions. The factory stock PCV valve does not completely seal against its stamped steel seat resulting in turbo boost air being forced back into the crankcase. Also engine blow-by is increased during WOT. The combination of engine blow-by and turbo boost air in the crankcase can over pressurize the crankcase and cause the oil pan gasket or the rear main seal to leak.
Lower crankcase pressure also improves engine longevity and performance as the engine does not have to work against higher internal engine pressure. Many expensive race engines have vacuum pumps to create negative crankcase pressure to increase engine horsepower. Valve cover breathers help to expel these high crankcase pressures and are recommended on each side of our turbo engine. This valve will reduce the amount of oily breather discharge that gets on the valve covers from the breather.
The Positive Crankcase Ventilation valve also eliminates inaccurate Mass Air Flow sensor readings to the ECM. Air flow is a major component in determining the correct air/fuel mixture under all driving conditions. When this valve is installed, all the air going past the MAF sensor during boost is utilized in the combustion process and not being diverted into the crankcase.
Under normal driving conditions, this valve functions just like the stock PCV valve; evacuating the proper amount of vapor into the intake manifold. The correct amount of metered vapor recycled into the intake manifold is critical to the ECM fuel calibration since GM uses a predetermined amount of recycled crankcase vapor in the combustion process. When the engine is in boost, or when engine vacuum drops below 2-3 pounds, this valve will automatically “positively” seal and prevent the boost pressure in the intake manifold from entering the engine’s crankcase.
You can test the stock PCV valve yourself by blowing back down through the valve or by pouring solvent back through the valve. The factory and aftermarket valves leak. The Turbo-Regals use a special calibrated PCV valve that is unique to these cars.
Our tests have shown when the Positive PCV valve is used with the valve cover breathers, a substantial reduction of oil build-up is evident on top of the valve cover. Thus proving the fact that less pressurized air is inside the crankcase during boost and WOT operations.
Over the years, others have tried to copy this valve, but have not been able to design the correct amount of recycled vapor to pass through this valve, resulting in erratic idle and poor drivability.
This valve is very easy to install in a few minutes between the stock PCV valve and the metal tube harness. The valve is complete with attached hoses, and requires no cutting or modifying of any components. No tools are required; just replace the factory rubber hose on top of the stock PCV valve with the Positive Crankcase Ventilation valve along with the supplied two hoses. This “Positive” valve is only 3/4-inch long and sits inconspicuously behind and below the fuel rail. This valve does not affect engine emissions.
