We ran it and flew it Matt. Mustang II. No fuel cloud with
   fuel injection. The cloud is caused by the reverse flow through
   a carb. The venturi cannot  tell the difference so fuel comes out
   regardless of the flow direction.

         Mark Steitle is flying one as FI p-port 3 rotor.

         Paul Lamar

    Paul,
     Do p-port engines have much of a tendency for fuel stand-off? It
   is a bit of a problem in piston engines especially with IR type
    intakes  because of the pressure pulse reversal when the intake
    valve closes.  A p-port does not really close the intake flow and
    stop it  momentarily. It gets redirected to the next side of the
   rotor as the  apex seal passes the port. Your charts of intake
    pressure show like  a sine wave. Intake tuning does affect this but
    the amount of  pressure difference should not cause a stand off
problem.
     Dale Davies

     There is no stand off with Tracy's efi. IMHO it is a carburetor
phenomena.
    The venturi in the carb cannot tell whether the air is flowing in
     or  out so to feeds fuel into the air stream regardless.
     Paul Lamar

   I don't think a carburetor p-port will have an issue with fuel
   stand  off for the reasons I stated. Automotive V8s will have it
   even with  a single carburetor. Even note the brown stain on the air
   filter  lid? If there is a tendency to have stand off with a carb,
   it will  do it with EFI also due to the pressure pulse. Throttle
   body EFI  more prone to show this phenomena. Port EFI masks it as
   the runner  length does not allow the fuel cloud to escape before
   being injested  again. A port EFI with the injectors at the open
   inlet end could  display the fuel stand off. A side port engine
   should have a  slightly greater chance of it, due to the longer port
   closing  between intake events.
   Dale Davies

   The carb p-port standoff is spectacular. This is a Weber carb.
     http://www.youtube.com/watch?v=NKJ00JsnS8A

   Paul Lamar

   Ok. So if you removed the Weber and installed a throttle body EFI
   from say a 454 Chev, the fuel stand off should be the same. If you
   extend the runners to the same length as the Weber carb tops and
   then put injectors just above the pipes, the stand off should also
   be similar. On the long intake of 24 to 28 inches, the stand off
   should be changed. At least the RPM that it becomes prevalent, will
   change due to the tuning effect. How was the Le Mans 26B engine for
   stand off? Yes the youtube video is spectacular and revealing.

   Dale Davies

   Here is about what your are describing and there was no stand off.
   We ran it with the top off the air box. I was surprised.

   Paul Lamar


 So Paul,

 If you moved the injectors to spray in the open tubes, do you think you
would get fuel stand off?  With the Weber carb, if you mounted ram stacks
like on the Can Am Chev engines on the throats, do you think you would see
the stand off then.  Possibly the length upstream of the fuel introduction
keeps it inside.  May increase bsfc or help it.  I know if you shine a
bright light down a carb, you can see a fog in the intake manifold.


 Dale Davies

 We saw a lot of stand off on the CanAm Chevy engines with and without
stacks.

 I designed a ram air scoop for the roof with boundary layer bypass on the
 the Nürburgring winning 2D.. We got much better MPG.

 I have not tried spraying fuel into the opening yet.

 Paul Lamar

Hi Paul, the 2D is one of my favorite cars.

Murry I. Rozansky

I did not do the body design. That came from Chevy styling.

I did the 2F.

Paul Lamar