Paul wrote:

I am now thinking of un soldering Tracy's pressure sensors, moving
them over to the runners and electronically multiplexing the data
back into Tracy's computer.

Paul,

I agree that having the pressure sensors just past the slide throttle
would be a good idea. It certainly would improve your ability to view
and massage the data. Do you really think that there is such a large
difference between the two intakes that you can't use the data from just
one to control both?

It seems to me that a major problem is that the pressure curve and
intake flow will change radically with RPM with a p-port tuned intake.
This could mean that a pressure wave integration during the open intake
period may not be a very precise basis to measure air flow to set
injector pulse widths.

I'll expose my ignorance by wondering if we want to control fuel to air
mass ratio why we can't measure integrated air mass flow into the plenum
with something like a hot wire device.

Fred O.

Well first let me say using only one sensor tap in one runner
may very well work fine as long as Tracy samples the data once
per revolution as I think he does from what he told me.

Second the pressure at the intake p-port can vary widely due
to the tuning effect. At some RPMs when the tuning is totally
out of phase and the throttle is still wide open the instantaneous
pressure could be half of what it is when the RPM is at the tuned
point in the runner.

Third Tracy system works perfectly if your throttle is upstream
from a large plenum. That is the scenario under which Tracy developed
the system and that is the situation with the vast majority of side port
manifolds out there. All pressure pulses are probably totally
gone and Tracy is truly measuring the total air flow going into the engine.
No need for a hot wire mass air flow sensor.

In a slide throttle p-port configuration on the other hand it is necessary
to mount the slide throttle near the rotor housing for idle purposes
so the pressure taps nearer the rotor housing see widely varying pressure
values depending on the RPM of the engine despite the fact the throttle is wide
open. You can't determine the total air flow with one short sample only.
You must take a series of equally spaced samples during the time the
intake port is actually open to determine the actual volume of air going into
that rotor.

Paul Lamar