setting ignition curves without dyno

[Roger Heflin]

That is actually more or less what the home dyno kits does.  You rig a
tape recorder to a inductive (timing light type) connector to the tape
recorder inputs to a spark plug wire.  You then take that data and
feed it inot a sound card, and the program figures out how fast your
engine was going at each time.  With this info and given car weight,
and gear, you can get pretty close to horsepower.  I would guess that
over the same conditions and over the same speeds that the results are
pretty easy to repeat.  And in this case the dyno data is exactly the
same load as you get when you are driving.

			Roger

On Fri, 13 Nov 1998, Michael Farrugia wrote:

> 
> 
> I do not think that just for setting the ignition advance you need to 
> know the real horse-power : all you need to know is the gain or loss 
> from a datum.  If you have an ECU which will tell you the speed of the 
> engine every say 5 millisecond and log it to a file, then you can get 
> the accelleration at every speed.  The accelleration is a direct 
> measuremnet of the power at that speed.  If you repeat this with verious 
> advance curves then you will get a good idea of which advance is giving 
> you the best acceleration.
> Of course, for these tests to be successfull all other conditions should 
> remain the same ie throttle position and load.  For throttle position 
> full throttle can be used while for load a flat strech of road and no 
> wind are a must.
> regards
> michael
> >
> >For one of the more innovative and cheapest dyno solutions I have seen,
> >check out what this guy has to offer:
> >
> >http://www.charm.net/~mchaney/homedyno/dynokit.htm
> >
> >Basically it measures ignition spark over time.  Given transmission 
> gear,
> >final drive ratios and vehicle weight you can calculate horsepower 
> using the
> >same formulae a conventional dyno uses.  The software he has written 
> does
> >just this.  Adjusting for drag can get you within a few HP of a chassis
> >dyno.
> >
> >I haven't tried it out (I have a G-Tech) but I might since it looks 
> much
> >easier and less finicky than the G-Tech.
> >
> >
> >Regards,
> >
> >Barry
> >
> >> -----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 Tom 
> Sharpe
> >> Sent: Wednesday, November 11, 1998 8:14 PM
> >> To: diy_efi at efi332.eng.ohio-state.edu
> >> Subject: Re: setting ignition curves without dyno
> >>
> >>
> >>
> >>
> >> Greg Hermann wrote:
> >>
> >> > >How about this idea..............actually build a dyno into
> >> your car.  A
> >> > >company called Land & Sea offer a product called "DYNOmite" which
> >> > >nonintrusively measures driveshaft torque and computes a host
> >> of parameters,
> >> > >including HP.    With such a product, every run on the street
> >> or track can
> >> > >be a dyno session.  I've been contemplating doing this to my
> >> project for
> >> > >awhile.
> >> > >
> >> > >Land & Sea is on the Web, and they are also at 1-603-329-5645.  
> I'd
> >> > >personally be interested in hearing from anyone who has tried
> >> this, or knows
> >> > >of anyone who has tried this.
> >> > >
> >> > >Thanks.
> >> > >
> >> > Not tried either it or the following described idea, but had been
> >> > contemplating doing as follows--mount a fore and aft oriented
> >> accelerometer
> >> > in the vehicle and include its output in a datalogging setup. A
> >> fuel used
> >> > pulse (or whatever sort of computed integration of fuel used)
> >> output from
> >> > the ecu could also be a very helpful thing to datalog in this 
> regard.
> >> >
> >> > ---Greg
> >>
> >> You should be able to determine crankshaft acceleration from the
> >> crank sensor....
> >>
> >> Just more clutter for the programmer.....
> >>
> >> Regards  Tom
> >>
> >
> >
> 
> 
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