Software Dyno...

[CSH-HQ]

On a v-8 disrupt every 7th ign pulse as 1st step
then 5th as second
every 3 as thrird stage

or use

MSD Multi step retard. and use the 3 timing inputs in combinination.

Charge two caps of a different resistir, and send to a 10 step bar graph 
display, pick out the "stages" you want.

Can use sudden rpm change also.

All these stagegies work.
Bruce


>Hi Dave,
>
>Been thinking about the same thing.  If you could just pull
>timing for traction control, say make it a closed loop for 10%
>tire spin, launches would be automatic!  Someone in England has
>a web page where they sell a traction control which acts like
>a rev limiter. ie. it cuts spark in alternating cyls.  They have a graph
>which shows friction vs wheel spin and usually around 10% is optimum.
>But this is for road course or F1 cars, I don't know about a drag
>race and slicks, but hey .. just try different settings.  Thier system
>uses ABS also, they have a sensor kit in case you don't have ABS.
>
>I think pulling timing would provide a much finer control without
>dumping raw fuel, and is more immediate than the dumb throttle control.
>I don't like the idea of shutting off injectors either, as I may
>be using N2O/alcohol also, and quickly melt the engine.
>
>Problem with VSS is that you can't detect tire slip unless you can tell
>the difference between the front and rear tire rotation.  You also
>have a problem with ABS sensors if the front wheels are off the ground!
>In this case you would need an accelerometer and compare acceleration
>to that you would get if there was no slip at the driving wheels.
>ie. x.x tire rotations = 5ft accelerometer integrates to 4.5ft.  The
>VSS would work fine in that case, though it might not be fine enough
>resolution.  Could also use some sort of ground looking radar for
>true speed (instead of accelerometer).
>
>I was thinking of this because of the problem of my front wheel
>drive car and getting optimum launches.  I don't have a problem with
>wheels coming off the ground! So if I put abs sensors on, and could read
>an extra analog input in my ECM. An external circuit that converted
>% wheelspin to an analog voltage could feed a little piece of code that
>pulled timing to maintain a certain voltage:)  Whew...
>
>Let me get my car on the road first ;)
>
>
>Dave Zug wrote:
>> 
>> 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
>