>I have been looking into fuel pressure regulators recently and there
   > appears to be some mis understanding out there on why you need
   > a pressure regulator that increases fuel pressure with boost.
   > The way I see it; a regulator that increased fuel pressure with boost
   > basically widens the dynamic range of of your electronic injectors.
   >
   > Injectors have certain pulse width range limits. For example the injector
   > may only open with a pulse width that is at least 2 milliseconds long.
   > This may give enough, or two much fuel, for idle. If it is too much the
   > engine
   > will burn more fuel at idle because the mixture is too rich. On the other
   > end the pulse width may be a maximum of 80% of the time which may limit
   > the fuel on the top end.
   >
   > 7500 RPM is 125 pulses per second for each rotor.
   > That is 0.008 seconds or 8 milliseconds total time available. If the
   > injector
   > can only be opened for 80% of this time than it will be opened only
   > 6.4 milliseconds. If you pules it more than that it may over heat.
   > That may not be enough fuel for full power. That leads to 2 injectors
   > per rotor so the injectors can be staged. One injector is used at the
   > lower HP levels
   > and the second comes in at the higher HP levels where both are used.
   > This is the scheme Tracy uses.
   >
   > This is all well and good as you now have a redundant system. Mazda felt
   > that
   > the RX8 engine needed six injectors, or three per rotor, to achieve the
   > proper
   > fuel flow over the entire RPM range from idle at 600  up to 9000 RPM with
   > a fixed
   > pressure regulator.  All this assumes your ECU  is a timed injection
   > system. In
   > other words it fires once per rev per rotor.
   >
   > What a boost regulator does is increase the fuel pressure and flow for a
   > given
   > pulse width as the boost increases. This in effect widens the HP ranges
   > at which an injector will function properly.
   >
   > --
   > Paul Lamar ...No rotor no motor.

   Paul,
   How is this regulator boosted?
   I know most regulators are fixed or manually adjustable, I can't imagine
   how
   a regulator could be automatically adjustable.
   I'm guessing an electronic signal to energize a restrictor of sorts?
   George ( down under)

   The spring side of the diaphragm is sealed and the manifold pressure is
   piped back to the regulator to increase the force on the diaphragm.
   That keeps the needle valve closed up to a higher and higher boost level.

   Paul Lamar ...No rotor no motor.

How much is that Vortech regulator?

Brian Trubee

$329. Some times you can get them on ebay for way less.
I don't think you need it Brian unless you are going turbo. Even
then other regulators do almost as much. The stock Mazda turbo
regulator does pretty much the same thing.