MoTeC M84 - Manual (Page 25)

MoTeC Installation 23
Fuel Lines
The fuel feed lines must be high pressure type and should be at least 8mm
(5/16 inch) diameter. The return lines should also be at least 8mm (5/16 inch)
diameter to ensure that the fuel is easily returned to the tank.
Use proper high pressure hose clamps to ensure that the lines do not blow off
under pressure.
Keep the fuel lines as cool as possible to avoid fuel vaporisation. The
temperature of the fuel will also affect the mixture due to the change in fuel
density.
Avoid fire risk by ensuring that all hoses and fittings are in good condition and
installed correctly.
Fuel Rails
The fuel rails must be free of any debris that could block the injectors. Welded
fuel rails can often cause a problem unless they have been properly treated to
remove all scale and debris and even then they may corrode and cause
problems. Aluminium fuel rails mounted directly on the injectors are
recommended as they do not suffer these problems.
The fuel rails must have sufficient volume to minimise fuel pressure pulsation
and resonance problems.
Fuel Pressure Regulator
The fuel pressure regulator maintains constant fuel pressure to the injectors
which is necessary to ensure constant metering of the fuel. Any variation in
the fuel pressure will cause a corresponding mixture change.
The fuel pressure regulator should be mounted at the end of the fuel rail so
that fuel is always flowing through the rail. This helps to avoid vapour locks.
Adjustable pressure regulators are available.
If Using Manifold Pressure Load Sensing
Connect the regulator port to the plenum as this ensures that constant
pressure is maintained across the injectors.
Note that this will cause the fuel pressure required from the pump to increase
as the manifold pressure increases.