Injector supply voltage & positioning.

[Lou Faustini]

>Hi there,
>
>I was discussing EFI in general the other day with a mechanic freind and
>couldn't convince him that it is best to run the injectors from full
>battery voltage, and use a compensation in the opening time of the
>injector for lower voltages.
>
>He thought it would be more logical to run the injectors from a fixed
>voltage source (eg 8 volts), then you wouldn't have to worry about
>compensating. I said it's comparable to using the starter motor at 8
>volts - if you've got the power on hand, why not use it? Does this seem
>like a reasonable reply to his question?
>

    Aren't injectors a binary-type thing? ... Either they are on, or they 
are off right?. I thought there was some mechanical hysteresys built in.
I assume if you were to drive them at very low voltages you might find a 
point where they are in a semi-open state, but I assume that that voltage
would probly be around 5 or less volts. I know that Toyota corp actually
puts a 2-ohm resistor in serise with their injectors. They are also 
low-side swithced. 

    Question.. What fuel pressure do you folks recomend running the
injectors at. I heard that the Ford-type injectors, like the ones used
on the Mustang V-8, run at about 40+psi. Is this true? That sounds like 
a real problem for the hobyst who would like to use Trak-Auto fuel line.
I know that my Holley setup runs 15psi. That is a little more reasonable
to work/play with.



                               ------ Lou Faustini