PC's and EFI

[Thor Johnson]

>  Charles Moore, astronomer and developer of the Forth programming
> language, used to use a five button 'puck' to chord 5-bit alphanumeric
> input to a portable computer while driving to work.  Of course, he had
> to write his own 5-bit character code, memorize it, and learn to chord
> the characters by pressing the proper buttons, but what else is there to
> do while parked in traffic on the Santa Monica freeway?

  Very interesting.  Is this where the Bat keyboard came from?

>  I don't think that I could drive and program at the same time; I tend
> to get tranced out when programming.  Of course, the average cellphone
> user can't talk and drive at the same time either...


I wasn't actually thinking of tuning the thing while driving it (my app
being FSAE and all.  The vehicle dynamics of ours forces you to work very
hard keeping the thing on course).

  Every time I see something like "ProTune" or whatever that logs the data
from
the ECM, I wonder, "what does this mean" during playback.  I know more about
electrons than gasoline, so much of the "history" is all but useless to me;
I really would like a vizualization thingy that you could use to *generate*
the tables reqd (since I don't have clue how they *really* ought to look).

One of the things that I keep running into with my supersimple efi is the
data logging question.  Telemetry would cost too much.  Anybody interface
a serial flash or sram (ie. cheap) to a 68hc11?

How much data is necessary?  If I log every point at every rev, I get
~5K/sec,
(@13K RPM) which after 20 minutes is about 5M.  I know I won't be running
full
RPM throughout the course (which will make timestamping this difficult), but
keeping that qty of data in the ECM seems a little much....but I don't know
what
I could throw out.

Parameters I would like to watch (guessing!):
 Bytes	Name
 2		RPM (actually, Trev)
 1x4		Each cylinder's injector width
 1x4		Each cylinder's oxygen sensor reading
 1		Intake Air Temp
 1		Engine Coolant Temp
 1		Throttle Position
 1		MAP
 1		*Gear / Speed
 1x3		*Accelerometer
  * indicates that I don't have these yet.  I am going for the "too many
sensors" award!

Any ideas on what I should throw out?  And how often I should log this?
Also, any help on interfaceing a high-capacity memory chip to the 68hc11
would be
appreciated.

TIA,
-Thor Johnson