Re: Injector Duty Cycle ... have data ... need advice

["Bruce Plecan" <nacelp@bright.net>]

> > What is the measured performance difference at 48 PSI, and 52 PSI?.
> > Compared this base line at 50?...
> > That's what matters

> Grumpy,
> You just confused me.  What does the measured performance difference
between
> 48, 50, and 52psi have to do with when fuel injectors need to be changed?

If you have max performance now, why would you want to change them?.

 >I thought that this was completely dependent on the Duty Cycle?

What changing injectors?.  Like body parts everyone has an opinion on this.
Some say 85% some 90%, etc.   Lots of variance is just due the particular
injector they're using.   Some one finds out something about the injector
their using, and writes about that, and then it's quoted to death as a
**Universal Truth** when its just a specific case.

>  Now, I do understand that higher pressures atomize the fuel better ...
but, once >you get up to 48psi the atomization at higher pressures (> 48psi)
isn't
> significant enough to provide a HP boost.

Again, the intake valve is open 25% of the time, and the injector is just
spraying at the floor of the runner anyway, Splain to me why the runner
floor like better atomized fuel.

 Are you saying that I should
> consider bumping the pressure up even higher than I am running now and
then
> reburn a new chip to lower the VE curves in order to decrease the pulse
> width (thus decreasing the Duty Cycle)?

Just raise/lower the presssure and record the performance,  That will tell
you when you got things optimized, for WOT.  Then work on your part thottle.

  If so, the question then becomes -
> What is the safe operating pressure range of the stock injectors?  I've
> heard that they hate high pressures.

Wassa posting at the syty list a year or so ago, they stayed "linear" to
over 100 PSI (the sy oem injectors)

Trouble is as you raise the pressure the volume that the pump can supply
drops.  So often raising pressure really just leans the motor.  That's why I
stay with monitoring the return line pressure.  You might have 60 PSI
showing on the high side, but if the return is 0, your outta volume.

Since my ecm bench is *dry*, I haven't verified it, but there is some
disagreement that operating pressures can effect the opening delay, and
closing rate.

Grumpy
>
> Tim
>
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