Hi Paul-

    Starting on the fuel plumbing for the engine.  What PSI pressure
    regulator am I looking for?  Any reason not to simply screw it directly
    into the fuel manifold?

    Mark Supinski



    You need a intake manifold pressure referenced fuel pressure
    regulator on the
    outlet end of the fuel rail. Manifold regulators have a 1/4 inch
    hose nipple to
    connect the regulator to the intake manifold in addition to dash 6
    or dash 8
    AN inlet and outlet lines. That is sometimes called a gage port for some
    strange reason. That increases fuel pressure as the throttle is
    opened and
    intake vacuum is reduced. The amount of fuel injected is directly
    proportional
    to the fuel pressure AND the width of the injector pulse from
    Tracy's system.
    This is what you need for Tracy's system.

    Don't use a fixed value pressure regulator. Usually these are ground
    adjustable
    but they don't change as the throttle is opened. Required fuel
    pressure is in
    the range of 40 to 60 psi. You could try a $134.95 MagnaFuel
    MRF-MP9925 from
    Summit but I am not sure it will not leak intake manifold pressure.

    If it don't have AN fittings don't use it. Too risky for an
    aircraft engine application. Leaking high pressure fuel and an in flight
    fire can ruin your whole day.

    I tried a $200 Aeromotive AEI 3109 unit from Summit Racing and was
    very unhappy
    as it would it would not hold a vacuum. Called Aeromotive and they said
    they all leaked and it was not a problem. Naturally I did not
    believe them.
    Find something else. Try TWM. Ask them if it leaks a vacuum.


    My first choice was a Mallory unit but Summit was back ordered at
    the time.

    Get a hand vacuum pump from the auto parts store
    hook it up to the gage or intake manifold 1/4 hose nipple on the
    pressure
    regulator and pump a vacuum. If it leaks down the unit is suspect.



I talked with Tracy C. about this, and his suggestion was the stock
Mazda unit.  Any reason that would not be appropriate for the P-Ported
13b?  Just wondering whether the P-Port would require more flow than the
stock can accommodate??

Mark Supinski

I don't know if the stock unit will handle the p-port engine flow
requirements. Probably worth a try. The biggest drawback to my way of thinking
is it uses hose barbs and hose clamps. Not something you want in a 50 psi
aircraft fuel system where a pin hole leak can result in an in flight fire.
I am not sure a fuel air explosion is not out of the question.
It does not pay to use cheap plumbing in any aircraft. Best to use AN fittings
in this application. In our seven years of experience so far it is always
the plumbing and other details that will get you. Mostly the plumbing.

Paul Lamar

Mark Here is the TWM regulator that Dave Leonard was using. If it
is good enough for the turbo it should work for your P-port.


Paul Lamar ...No rotor no motor.

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