Now that I am done traveling for awhile I am going to get serious
about measuring the p-port intake manifold pressure wave at different RPMs.

I will order this low cost data acq system and hook it up
to the kind of pressure sensors Tracy is using.
That way we don't need to open Tracy's computer.
Also we will learn a lot about tuned p-port intake systems on the
rotary. Right now we have only a snippet amount of data from
Mazda.

I'll also trigger it off the ignition pick up so the data
can be correlated with the ignition pulse angle.
http://www.labjack.com/labjack_u3.php?prodId=52


I don't need this info for the 555 system or the Holley carb but
there are a lot of people out there with Tracy's system that need help.
The 555 uses the mass airflow sensor that works far better than just
sampling the intake manifold pressure once per rev.


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I found one I like better. It is about the size of a credit
card. It has a stand alone mode that saves data to a
USB stick. USB sticks are up to 32 gig
and that is weeks of data even at 32,000 samples per second.
It also has drivers for Linux if you want it to work with
an EeePC.  It has eight 12 bit(resolution is one part in 4000),
zero to 5 volts analog inputs if you want to use it as a engine
monitoring data aq system. One of the many digital
inputs (on off) could be used for the ignition trigger to
correlate the data to the e-shaft position.

The price is lower and most of the software is free.

http://www.hytekautomation.com/Products/IUSBDAQ.html


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I just ordered some Free Scale 2.2 to 36.5 psi pressure sensors from
Digikey and the price dropped to $10 bucks each. I suggest if you
are having trouble tuning Tracy's EFI you might want to see what is going
on with the manifold pressure.


Paul Lamar