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911st 911st is offline
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Join Date: Jan 2004
Location: Sacramento
Posts: 7,269
Control pressure is what the WUR establishes to effect where the metering pin is positioned relative to air flow.

System pressure is the pressure in the head that is allowed to escape out through the injectors.

Differential pressure is the lowering of the pressure behind the diaphragm in the head that presses against the internal orifices that are the pathway to the injectors. As the metering pin advances, it increases this differential so more fuel is delivered.

At least I think that is how it works.

There is a pressure regulator built into the head just before where the excess fuel escapes to flow back to the tank is what determines the system pressure. Some shim this to raise the system pressure so more fuel is delivered. The problem with doing this is this increase comes in at all points including idle and cruse.

By adding another boost modified fuel pressure after the head that is progressive with increases in boost, we can keep our AFR's stock off boost but get more fuel on boost.
Old 05-03-2009, 03:27 PM
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