TZR250 3MA

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Dyno correction 2.0

Own Dyno

I need to ad this part to my dyno correction.
After discussing this with the dyno builder, I really made a mistake.


My calculations for the mass off the drum where absolutely right with
5,51kg/m2, no argument there.
But my biggest mistake was that this is a setup for a engine dyno (engine drives flywheel with chain) that is 1 : 1
A chassis dyno runs with the rear wheel the flywheel and that creates a certain
slip and friction.
To get a indication how much that is I needed to Perform a certain "run with losses"
That is in (short terms) a dyno run without pressing the stop button so after the power measurement it keeps measuring the energy (power) needed to stop the flywheel.
Ones measured the program ad's this to the curve so you have a correct measured dyno run.


Here I have done the run with my street going tzr125
Measuring a 22,5HP
You see clearly the min part on the bottom The slowly decelerating drum

 

Now you select in the program.
"calculate with losses"

 

If you have done that the program ad's the losses to your measured dyno run.
Now you have 25,7HP

 

Theoretical you need to measure this with every bike because there all different. (tire pressure, width, profile)
But we only measured the friction with this measurement and not the slip.
While accelerating, the rear wheel (driven) has an certain slip between wheel and drum.
This slip is very difficult to calculate so I leaf this part out, small note: on the street the rear wheel has a certain slip to.
Without calculating the slip in your software, this dyno now gives a good
road based power curve.

To prevent you need to do all the runs with the "power with losses" calculation you add a certain percentage to the mass off the drum
In my case I need to go from 5,51kg/m2 to
6,29kg/m2 to get 25,7HP

Here you see the "power with losses curve" without correction with the new set
6,29kg/m2 mass flywheel.
I have exactly the 25,7HP back

Because its not handy to change this manually with every run you make.
You set the
6.29kg/m2 in your software and all other runs you make will be calculated the same















Here you have a couple off runs with the
new setup

 
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