MoTeC M84 - Manual (Page 26)

24 Installation MoTeC
If Using Throttle Position Load Sensing
Leave the regulator port open to the atmosphere, unless the MAP sensor is
connected to the manifold as is recommended when using idle speed control,
in which case the regulator port should be connected to the manifold.
Fuel Injectors
The fuel injectors meter the fuel by opening for a short but defined time once
per engine cycle (sequential operation).
The injectors must be wired in the firing order of the engine.
Sizing
The size of the injector determines the maximum amount of fuel that can be
delivered to the engine.
As a rule of thumb the engine will require about 5 cc per minute per horse
power for petrol or gasoline. For alcohol a higher flow rate is required.
For example: A 600 hp V8 will require each injector to flow at least
600 hp x 5 cc/min/hp/8 injectors = 600 x 5/8 = 275 cc/min.
Note that the flow rate of any particular injector is dependant on the fuel
pressure applied to it.
Sometimes oversize injectors are used to maintain lower duty cycles, since
high duty cycles reduce the effect of sequential injection, because the
injectors are turned on for most of the time. However this can affect idle
fuelling as the injector may have trouble delivering small amounts of fuel.
Flow Rate Matching
The flow rate of injectors can vary between injectors of the same type. It is
advisable to match the flow rates of injectors by testing each injector on a flow
bench.
Fuel Pressure
The fuel pressure applied to the injector will directly affect the amount of fuel
that the injector delivers. Doubling the pressure however only increases the
fuel flow by about 1.4 times.
Most injectors will only operate correctly over a certain range of fuel
pressures. If the pressure is too low then the fuel may not atomise properly. If
the pressure is too high then the injectors may not turn off fully. Many injectors