<all> home dyno kit??

James Montebello jamesm at talarian.com
Thu Jan 28 01:27:54 GMT 1999


> 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).

 P = mass * (dV/dT) * V

 P is in Watts (/746 for HP)
 mass is in kg (*2.2 for lbs)
 dV is "delta V" (change in velocity, in meters/sec)
 dT is "delta T" (change in time, in seconds)
 V is in meters/sec (*3.3 for ft/sec)

This doesn't compensate for drag or driveline losses, which
the $40 software attempts to.  This does give you a repeatable
number with identical conditions, though.

james montebello



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