« Reply #40 on: August 24, 2009, 11:33:46 pm »
As John quite rightly says the pump upgrade is to increase flow/quantity as opposed to pressure. What this does though is enable a greater pressure to be maintained in the fuel rail in the mid rev range by maintaining a higher volume of fuel in the rail.
The OEM fuel rail has a pressure relief which IIRC is maxed at approximately 130Bar.
The issue arises because the pump is being driven directly from the cam which means it is directly related to engine speed. At mid range engine speeds the OEM pump cannot flow enough fuel to feed a modified engine.
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