D.4 fuel pump capacity – Haltech E6A User Manual

Page 110

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Staging is enabled on the Fuel Setup by selecting the "Staged" Injection Mode. The Staging
Bar is also defined on the Setup (see Chapter 3).

Once staging is enabled, the bars on the Fuel Maps will change appearance. The bars that
indicate both sets of injectors firing are a different colour to those corresponding to primary
injectors firing alone.

When staging injectors, drivers 1 and 2 are primary and drivers 3 and 4 are secondary. Since
the number of primary drivers is halved, and since you may wish to employ higher power
secondary injectors, ensure that you have sufficient driver power to run the injectors properly.
(See Appendix C)

D.4 Fuel Pump Capacity


You should ensure that your fuel pump is capable of supplying sufficient fuel to feed the engine
at maximum power. With the engine switched off (injectors closed) feed the return line of the
fuel pressure regulator to a measuring container. In the case of a turbo- or supercharged
engine, pressurise the manifold pressure port of the fuel pressure regulator to the maximum
boost of the engine. This is necessary as the flow rate of the pump decreases with output
pressure. Power the pump for one minute and calculate the hourly fuel flow rate of the pump.

Since the pressure regulator operates on a return system, there should always be fuel being
returned to the tank, even when fuel flow to the engine has reached its maximum. If this fails to
happen, the fuel pressure will fall out of regulation. Therefore the fuel pump must be capable
of delivering significantly more fuel than the engine is going to use. As a guide, the pump
should flow 30% more fuel than consumed by the engine.

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