<all> home dyno kit??

[Dan Llewellyn2]

This dyno kit assumes (among other things) you are on
level ground.  At least were I live, level stretches of road where
you can get up to speed are rare.  If they incorporated the data
from a G-field measuring device, like an Analog Digital ADXL05,
you could calculate horsepower even if the road was not level.
Combined with an ignition signal (ignoring timing changes), you
could get a pretty good idea of performance.

I have the G-Tech and although it mostly works, it also assumes
level ground, no suspension loading, etc.  I have found it almost
impossible to get repeatable runs - but I don't have access to
a drag strip either.

Dan L

Roger Heflin wrote:

> 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