Subject: P Ports CF Manifold
From: ACRE
Date: 5/21/2004, 6:16 AM



Alex Madsen wrote:


Have no fear. I am working on a P Ports CF Manifold as well as a
conventional manifold. It looks like the PP manifold will be much
easier
to construct (cheaper). I have some questions about PP manifold
layout.



1. Where is the throttle body placed? I in the R26B it looks like the
have it right next to the engine. Is it ok to put the TB on the end of
the runner?

2. Fuel injector placement. In the R26B they say they used an air
funnel
injector and a PP injector (sae 920309 fig 14). However the air funnel
injector does not appear to be in any of the othere figures (fig. 4 &
5)

Was the air funnel injector eliminated? If not is it in front of the
TB?

Regarding the length of my conventional CF manifold, I may have been a
little unclear about the length of the manifold. The "Port to Port"
length is 26 in. The Port to plenum length is 13 in. I just found out
today that the port to plenum length of the of the R26B runners at @
6500 rpm is about 13 in. This means that Eds length calculations are
in
the right ball park. The question now is witch is greater the dynamic
intake effect or the resonate tube effect. I guess I will just have to
build on of each and put them on the dyno.

Alex Madsen


Alex,  the throttle bodies are located right at the ports.  They are 2"
O.D. They are parallel to the horizontal thrust line so the runners
need turn 90º to go up the side of the engine and another 90º to go
over the top.  There are four injectors, two for each runner.  These
are required by Tracy's controller.  All four injectors share the same
fuel rail--refer to Paul's rhino drawing of this. The runner length
should be 22 inches for the 6000 rpm and somewhat shorter for 7500 rpm.
  Maybe someone can suggest a compromise length that will work well
enough throughout that rpm range.  I have a 12A housing into which I
can install a dummy throttle body and send to you.    Jerry


 
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