D.5 fuel rails and pressure regulators – Haltech E6S User Manual
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If you cannot achieve the required fuel flow from one pump, you can employ two pumps in
parallel. If you choose to use a low pressure pump to augment the fuel flow of a high pressure
pump, place a check valve after the low pressure pump.
D.5 Fuel Rails and Pressure Regulators
A long fuel rail with narrow internal diameter will suffer from pulsation in the fuel rail. The
internal rail diameter should be around 12mm (½"). Even so, oscillations may occur,
particularly if the injectors are large. A fuel damper can help in removing these oscillations. If
running a multipoint setup, batch fire injection will also reduce oscillation amplitude.
Oscillations may occur only within a certain rpm range, so a fuel pressure meter should be
monitored throughout the driving range of the engine.
On V configuration motors, it may be more practical to employ two regulators, one on each
bank's rail. The fuel from the pump can be split to the two rails, and the return line from the
two regulators can be joined. Since pressure regulators work within certain flow limits, this
may also save having to purchase an expensive high pressure / high flow regulator.