Paul,

I was looking at the web site at Mark's P Port installation specifically
the plenum.  What is the function of the plenum?  Does it trade high
speed air for pressure? The web site says it is to contain the vapor
cloud that was apparent on the U tube dyno run.  The web page states
that it is not needed if injection is used.  I just wanted to get a
clarification on it.  How big should it be?  Is it volume or a specific
size?  I have space constraints and may use part of the lower cowl
as a surface for the plenum. I would like to place injectors in the
tubes rather than in the plenum.  If the hot wire MAF is mounted on
ther entrance to the plenum does this pose a potential hazard?
What are the dimensions for the tooth wheel for the 555 EFI design.
Thanks for any help.

Joe Berki
13b P Port


It keeps the vapor cloud from floating away :)
The web site is wrong. What web site? Who's web site?
As large as possible.
The hot wire mass airflow sensor does not present a problem at
the entrance to the plenum. It is really just a warm wire.

The shape of the toothed wheel depends on the ignition type.
Probably 2 teeth 180 degrees out.
It can be 2 inches or 8 inches in diameter. It matter not
as long as tooth is pointed.

Paul Lamar


Paul,

I went back an looked at your website to make sure I had said something
wrong, but under the section for intakes and slide throttles the bullet
that
calls up the Youtube video of the cloud states that it is'nt a problem
with
fuel injection.  I think it is as Mark has a plenum on his Mustang.  The
more I look at my engine compatment the more ideas come up.  I think I
will
mock up a plenum divided into two parts.  The forward section will be
exposed to the small scoop that points forward under the strake and will
contain the MAF sensor with a conical air cleaner.  It will dump into the
aft section where the 22" runners from the rotor housings will end and
perhaps the best way to mount the injectos is to place them in the box
pointing at the ends of the runners and use velocity stack type ends.
Plenum wil be aluminum.

Ordered a stainless exhaust header flange from Mazdatrix today.  The
entire
exhaust system next to the engine will have a heat shield.  Thanks for any
help.  Looking forward to seeing the data off of Mark's engine.

Joe Berki
Limo EZ
2nd gen P Port

OK Joe. I see it. Thanks I'll fix it. I don't want to give that
impression.
Although it might not be a problem with the injectors mounted
down near the port there is no point in taking chances.

Paul Lamar

Paul,
In a P Port, is the optimum location for the injectors as close as possible
to the rotor housing?  Just upstream of the slide throttle?

Joe

It does not make a whole heck of a lot of difference.
Slightly lower fuel burn if you put them at the start of
the runners.

Paul Lamar