[Diy_efi] Re: if YOU were bored enough to disassemble...

[Dave Gallant, 12 Point Racing]

on 8/26/02 3:21 AM, Marcell Gal at cell at x-dsl.hu wrote:

> Hi Dave, 
> 
>> "Dave Gallant, 12 Point Racing" wrote:
>>> have as much EE in me as a lumberjack. My end goal is to be able to flow
>>> chart the entire code base within an EPROM on my particular ECU/EFI
>>> hardware, thus being able to edit it once complete.

> However it seems to me that it's 10..20 times more work
> to successfully twiddle with your factory computer's EPROM content
> than build an efi board of your own.

Understand, and agree completely actually. I am actually working towards
this end at the same time (custom ECU), as it is the only way to get some of
the features I desperately want, but this is the "longer" road right now as
it is a project that a few of us are working on in the little spare time we
all share.

> Do you really have that much motivation (and hair)?
> Want to tune dozens of such engines with little investment?
> Think wice :-) 

I am only looking to be able to tune my own bike, much less anyone else's
;). Once you stray from the proven path and begin changing
cams/cranks/head/port profiles/exhaust lengths, it becomes impossible to
find an aftermarket chip that can take advantage of it. I may be flowing 15%
more air in certain spots, but without being able to tweak the fuel/timing
(not to mention rev limit) I would be wasting my time with the
modifications.

Also, I think the motivation may be there due the overriding fact I cannot
afford any hardware related failures during operation. My motors are built
for racing only, and the level of sustained vibration/heat/anything may
prove unpredictable on new hardware, hence me being hesitant to put all my
eggs in that basket (nuts and bolts vibrate loose or snap off from time to
time). I am sure a resilient system could be designed from the ground up,
however not by me, and I have a stock ECU from the factory that has proven
itself time and time again. I thought I would at least give this route a
"go" and see what I could make of it.

As I understand it, this ECU is really nothing special, and seeing as this
is twin cylinder motorcycle with a ignition sensor that detects some missing
gear teeth as the large pulse (48 small teeth pulses, 1 large pulse from 2
missing teeth - total of 50 steps per revolution) - I am told this is not a
daunting proposition to design and build. (2 injectors, 1 TPS, 1 baro, 1 air
temp, 1 coolant temp) The difficult part is the acceleration and
deceleration logic for the motorcycle's code. Unlike a car, less horsepower
may actually prove faster in lap times if it has smooth on/off throttle
transitions. Fuel injected bikes are notorious for being "choppy" and
difficult to ride due to it being hard to get on the gas while at max lean
angle with limited traction. There has to be some sort of logic that
predicts your speed of TPS and RPM increase and softens the power delivery
slightly to allow for smooth transitions, or some other logic scheme that
does the same thing. It goes without saying here that emissions are the
least of my concern, so running stinky rich at certain points of a map is
fine and dandy if it accomplishes the task at hand. Another limiting factor
is size - as I can not strap on a laptop to the tail section of my bike. :)
Possibly the last limiting factor is the need for the ECU to be able to
handle 15K+ RPM without loosing its head. :)

I have posted a ZIP file with the BIN, (hopefully) the correct disassembled
code, and pics of the ECU for anyone even remotely interested in poking
around:

http://www.12pointracing.com/Ducati748Files.zip

> Brian's advises (start from the signals and map the code
> from there) are very good if you really want to do it.

I am afraid I do not have the skills to go about this in any meaningful way
just yet, but what I am learning is proving fun so who knows how far we will
get. Thanks for the discussion here however - keep the ideas coming.


----------------------
dave at 12pointracing.com
MRA #31, AMA #232




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