Software Dyno...

[CSH-HQ]

You have roughly three VSS pulses per tire revolution.
Most "tolerable" slippage is jsut in the first three tire revs.
So Ignore the first 10 pulses.  Stage at the same general vss pulse stage, 
and then count enough turns for 400'-800'. use a $20 stopwatch tripped by a 
4066 and 555 for the on-off pulses (on the watch).
You will truely be amazed by finding the trends that your car respnds too 
how easy, safe, accurate this all is.
  By the way, this ain't theory or maybe ar should could I'd like, it's what 
I've been doing for years for street stuff.
Bruce


>This tradeoff I'd be willing to live with, others may not so our 
>development time may not be best suited for this task.
>
>Mine wont catch second and with the 2.73 rear is hard to mess up a 
>launch also. An algorithm can detect and flag or account for 
>slippage.. maybe its a worthwhile compromise. Tire slippage would 
>also affect RPM based readings, as well as ABS sensor based readings. 
>VSS pulses would give rear wheel performance figures, another bonus 
>to me. Hey if I can measure and tweak to eliminate rear wheelspin on 
>a WOT takeoff.. I've implemented a sort of static traction control!
>
>Okay so what pin / color wire for the VSS on a 165? whats the signal? 
>+- 5v? wouldnt that be convenient.
>
>
>> Date:          Thu, 19 Aug 1999 15:02:31 -0400
>> From:          Ken Kelly <kenkelly at lucent.com>
>> Organization:  Lucent Technologies
>> To:            gmecm at efi332.eng.ohio-state.edu
>> Subject:       Re: Software Dyno...
>> Reply-to:      gmecm at efi332.eng.ohio-state.edu
>
>> Can't use VSS if you have any tire slippage. VSS will work
>> with small motors, but not with a fast car.
>> 
>> 		Ken
>> 
>> Dave Zug wrote:
>> > 
>> > If we replace ABS with VSS as the input then it may be more
>> > universal. I have no ABS so I'm SOL if this is the input.
>> > 
>> > If your software can simply turn parallel input into a binary or text
>> > file of "times between pulses" or "pulses per second" values I can
>> > take it from there and do the UI in windoze. If you have a schematic
>> > I can test it with the scope.
>> > 
>> > > The ABS is right behind the drivers seat and you can use the signal from
>> > > it to give you a reading on tire rotation.  The corvette has 43 pulses
>> > > per wheel turn which is fed to the ABS system at 250mv per pulse, I have
>> > > a preliminary schematic using radio shack parts to store and forward 4
>> > > channels through a parallel port but don't have the expertise in
>> > > electronics to put it together.  A busy computer engineer friend did the
>> > > circuit design but has too many  projects going on to help.  I have the
>> > > software in a draft using clipper if I could get the interface worked
>> > > out.  It could be used for any sensing device using the software to tell
>> > > it what the channel represents.
>> > > Anyone interested in helping make it happen?
>> > >
>> > > Tyler
>> > >
>> > >
>> > >
>> > >
>> > ~~~
>> > Dave Z. www.delanet.com/~tgp
>> 
>> 
>~~~
>Dave Z. www.delanet.com/~tgp
>