Technical Questions?

Call Mike at 615-457-3192

Tuesday - Friday

No call backs on Monday

Contact Us

307 White Bridge Pike
Nashville, TN 37209


9:30 AM - 5 PM M-F CST


Sales & Orders: Toni, Shannon, Mike


Tech Questions returned when time permits
Email Tech

FAX: 615-873-1876

Email Us


Hilborn Boost Referenced Fuel Flow Control Valve

Print Friendly, PDF & Email


Fuel Flow Control Valve

Hilborn Turbo/ ProCharger Boost referenced Flow Valve

This valve provides a way to limit the flow of fuel away from the engine during boost cycles.

The way it works is by normally being wide open with no boost.

When boost is sent to the valve, from any source where boost is available before the butterfly, to the -6 fitting on the valve it causes the valve to begin to close.

More boost which is regulated by the “Air Valve” will cause it to close more quickly – Less boost will make it close more slowly.

The Air Valve uses “Pills” to allow more or less boost to get to the Turbo valve. Larger pill = More Boos t= Quicker Closing = more fuel to the engine sooner.

The -12 Fitting gets returned to the tank. The -12 wants a fairly short hose or direct fit to the tank with no turns if possible.

The -8 Fitting receives the fuel from a direct source from the pump. Fuel pressure BEFORE it gets metered.

So in summary:

Smaller pill in the Air Valve makes it in effect leaner.

Larger pill in the Air Valve makes it richer.

Hilborn F510A Air Valve is recommended , using F565 Hilborn pills. You should have pills in the .050 to .100 range on hand.

Alkydigger Fuel Injection