Thanks for the response, guys! I know theres no comparison between this device and a real load dyno. Would be great to have the Robi, but I'd rather put my limited race money into batteries/motors ect. I do enjoy playing with this cost-reasonable device, but the Integy instructions aren't all that helpful. Like you guys, I suspect that this thing tells us indirectly several things. I'm just not sure what I'm looking at.
I took a new monster stock and dedicated it as my test motor. I took several pairs of different brushes/springs and tested them at 3-4 volts. I have developed a method of using this device, so that I do the same thing on each pull, then write the results down. I have settled on three volts as my test standard.
The biggest result that I have realized was not in the brush/spring combo's, though some were better than others. The biggest gain I saw was in how I broke-in and maintained the motor!
My old method was to turn the motor, put in new brushes, and break it in in the first heat, between the start grid and the first turn (Barry Baker, if you see this, quit laughing).
It looks as if this isn't the best way. By a slow break-in, the numbers are higher and stay there longer....
By the way, does anyone know what the "Comm Condition" is measuring? Is it resistance, or what?