Pump Pressure

[Jon]

How low a pressure can Ford 5 liter injectors accept and still spray
properly?  TVR Jon

Daniel Ciobota wrote:
> 
> Wayne,
> 
> What you describe is pretty much the way an FMU (fuel management unit)
> works for blown cars.  Those cars use the stock fuel pressure and fuel
> timing curves until boost occurs.  The FMU increases the fuel pressure
> in relation to boost (still at the stock fuel pulse timing), effectively
> delivering more fuel to the chamber.  Be aware, though, that dropping
> fuel pressure significantly from factory stock pressure (39psi on a
> mustang) may also affect fuel spray pattern at the injector; those units
> are calibrated with orifices which require a set minimum pressure to
> give a good spray pattern.  On the other hand, increasing the pressure
> (within sane limits) doesn't seem to affect the spray pattern at all.
> There are some people running up to 100psi and still using stock
> injectors with no problems.
> 
> Hope this helps,
> 
> Daniel
> 
> Wayne.MacDonald at zurich.com.au wrote:
> 
> > Does each injector require a set pump pressure to work correctly or
> > will an
> > injector still put out a good spray through a range of pump
> > pressures?.
> > I ask this because I was wondering if it would be possible to vary the
> >
> > injector pulse from long at low revs to short at high revs and control
> > the
> > fuel passed by the injector by regulating the pump pressure.
> >
> >      Wayne.