# Re: K24 and boost - more on WGFV

```> >
> >  If this were an electrical system, the line to the wastegate would
> >  definitely be an output and the other two inputs.  The fact that
> >  one is usually negative relative to the other doesn't change it.
> >
> >  Orin.

> But this is a controlled flow fluid DC switch, not an electrical one.  In a

Electrical <-> air/fluid pressure analogies work very well...
Voltage is equivalent to pressure.  Electrically, electrons
move.  Here we have air molecules moving.

> pressure experiment with a DC switch, you have a feed, a source and a vent.
> The feed is an input, the source is an output, the vent is also an output.
> How would we measure it as an "input" if, regardless of value, nothing
> happens?

Think _absolute_ pressure.  The WGFV switches the upper wastegate
chamber back and forth between two different absolute pressures.

> Bottom Line is this:  DC are values that are measured.  They are measured in
> terms of a percentage of feed (input) values which assigns an output value
> (ouput = pressure at top of WG), and excess.  To address the off or open
> switch to vacuum at turbo inlet as an input function has no measurable value
> or function, because this off state doesn't cause anything measureable to
> happen.

Oh but the pressure at the vent does have an effect.  It _is_
an input to the system.  0% duty cycle, pressure in wastegate
upper chanber = 'vent' pressure.  100% duty cycle, pressure
in wastegate chamber.  Some horrible function of duty cycle inbetween.
The pressure at the 'vent' doesn't go away once the FV starts
cycling...  The DC required to maintain a given pressure in the
wastegate _will_ change with different pressure at the 'vent'.
Vent to atmospheric and you would require slightly lower DC.
It may not be very significant, but I'd still call it an input
to the system...

> Call it semantics, I think it calling a FVDC "vent" an input, only causes
> confusion here.

I have no problem calling it a vent... and leaving it at that...

Orin.

```