Paul,

    The "brain trust" had proceeded quite a ways toward defining an
    inexpensive package of hardware for recording intake and exhaust
    pressure pulses. Could this be finished to the point of defining model
    and part numbers with suppliers and prices for all the items needed for
    a complete system - including the PC software?

    I'd like to see if it would be practical to assemble a package in time
    for your next dyno run. Perhaps we could share the cost if it's fairly
    affordable.

    Philip


    My dyno run is coming up soon. I'll be out of the country starting
    on the
    9th of Nov for ten days so it will have to be in December.

    We need at least two pressure transducers. I have one of Tracy's systems
    with the dual transducers so I can set that up. All one needs now is
    a data
    acq system that samples the sensors once every millisecond or so. I have
    a Tektronix storage scope that can do that. A battery powered
    digital data acq
    system with a USB output would be more convenient.

    What I really need is a body to take charge of this part of the project.
    Where are you and what are you doing around the first of December?
    Do we have any other electronic types that will volunteer?

    Paul Lamar ...No rotor no motor.


November and December are out for me.  January and February should open
up.

It looks like you have the pressure transducer detail solved.  What
would make a good data acquisition board with a USB output, and what
software would we have to use with it?

I'd like to find something that's more solid numerically than snapping
pictures of an oscilloscope screen.

Philip

If you get a recent copy of Nuts & Volts Magazine or Circuit Cellar there are some adds
for data acquisition systems. http://www.nutsvolts.com/
or Circuit Cellar http://www.circuitcellar.com/

Paul Lamar ...No rotor no motor.

Hi Paul/Phillip;
Have you guys built a variable length intake/exhaust system to go with
the data acquisition system?
That data would go a long way to identifying the sweet spots.
Cheers
Cary

-----------------------------------------

No but will you loan us yours? :)
Paul Lamar

---------------------------------------------

Paul & Phillip,
Keep in mind that this data is in the low audio frequency range of 100
hz to 200 hz.   If  Tracy's transducer output can be conditioned to be a
microphone level or line level signal, then ordinary digital audio
recorders will work for capturing the data.  CD quality audio recording
would show all the detail we would need for this project.  Some MP3
players have audio recording capability;  The Creative, Zen V Plus has a
line input, 2GB of memory, USB, and a lithium rechargeable battery.  ($
78 at Wal-Mart).

I have an appointment I must keep at the moment.  Some other recording
options come to mind.  I'll write again tonight.

Aubrey Thompson

------------------------------------------------------------
Here is something I found using google.

http://www.labjack.com/labjack_u3.php?prodId=25

One of the inputs could be connected to the crank angle sensor
to reference the intake wave to top dead center.

Anybody with Tracy's system can use this. All you need do is tap off
Tracy's pressure sensor which is an analog signal .5 to 4.5 Volts. It is activated 100%
of the time and Tracy only samples it for less than a microsecond at some arbitrary
point in the engine cycle.

You will need a simple two resistor  voltage divider to reduce it down to 0 to 2.5 volts
for this data acquisition system.

BTW this is not on my high priorities list as I am focused on mechanical
fuel injection. I already know what the optimum length of runner I need as I
am merely copying the work done by Mazda for the p-port Lemans engine.

It is also of academic interest only as you can not change
the exact time Tracy's samples the pressure sensor. On the other hand IF
you are designing a simple PicAxe system to control fuel injection it
could be essential info.