setting ignition curves without dyno

[Michael Farrugia]

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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