Haltech E6A - Manual (Page 108)

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Appendix D
Fuel Systems & Staging
The best EFI installation will yield poor results if the fuel system does not meet the demands of
the engine. Insufficient fuel flow can lead to engine lean out and detonation which could cause
serious damage. For the safety of your engine, we urge you to check your fuel system's
capacity and ensure that there will be sufficient supply at all times. A fuel pressure meter
should be used during testing and tuning to ensure that fuel pressure does not fall out of
regulation i.e. that the pressure does not drop or oscillate.
This appendix offers guidelines to testing your fuel system and suggests some solutions if there
are supply problems. If you find you need to modify your fuel system and are unsure what to
do, contact a Haltech dealer for advice.
D.1 Fuel Requirement
If you can estimate the power output of a gasoline engine, you can make a reasonable guess at
the fuel flow requirement. A simple rule of thumb, thus, may be expressed in metric or imperial
units.
Every 100 hp needs around 50 lb/hr (8.0 US gal/hr) of fuel
(6.6 Imp gal/hr)
Every 100 kW needs around 670 cc/min (40 L/hr) of fuel
This assumes a brake specific fuel consumption of 0.50. The actual fuel flow necessary by
injectors and pump are likely to exceed a figure derived this way. This is due to the overheads
in injector dead time and pumping return fuel to maintain regulation.
D.2 Injector Flow Capacity
If you have purchased second hand injectors, or have removed the current injectors while
doing work on the engine, we strongly recommend that you clean and flow test them. If you
have bought new injectors, it is worth flow testing them anyway if you do not know their flow
rate. Make sure that you test the injectors at the fuel pressure that your regulator is operating.
Fuel is dangerous. Beware of flames, cigarettes,
electrical sparks, etc .