<all> home dyno kit??

[Ward Spoonemore]

This is because the 8192 sample time is maxed at about 8 frames/sec. This is
an interrogate respond handshake system and it has real time interrupts to
prevent the engine from dying from over eager scanning.
Ward

-----Original Message-----
From: owner-diy_efi at efi332.eng.ohio-state.edu
[mailto:owner-diy_efi at efi332.eng.ohio-state.edu]On Behalf Of Roger
Heflin
Sent: Wednesday, January 27, 1999 5:35 PM
To: 'diy_efi at efi332.eng.ohio-state.edu'
Subject: RE: <all> home dyno kit??




On Wed, 27 Jan 1999, Mike Pitts wrote:

>
> Seems like if you had a fast (8192 baud) home brew scan tool,
> you could measure RPM and MPH and make the same calculations,
> probably a bit more precisely since you would have MPH as an
> input rather than a calculation.
>
> Anyone know the math for this off-hand?  Might as well add it
> to my cutom scan software (for 16198625 PCM's only, sorry).
>
> Cool idea though.  Very creative with the inductive coil into
> the microphone jack.
>

I tried using the diacom data to get this sort of info.  I have 7
samples per second 8192 baud.  It does not work.  The rpm and mph are
too coarse.  1mph and 25 rpm don't give enough resolution to be able
hp over a short range.  To get reasonably smooth data I was having to
average over 7-10 samples (almost a second, and a pretty wide rpm
range). At 7 samples per second, the mph takes several samples to
change, so you really cannot get accurate acceleration numbers, and
this was the reason for having to average over a wide range.

If you adjusted the computer and had some way to get more accurate mph
numbers then it would probably be workable.  But with 1 mph resolution
it won't work very well.

You might be able to setup an interpolation type equation for the mph
and get alot better guess.   I have a program (quick basic) to read a
diacom dbf file and do this sort of processing.  I will revisit doing
this, since I already have some code that may work with interpolation.

				Roger