Wheel Dynos - What are they good for
Wheel dynos are great for tuning but not for comparison to other
engines, dynos, or even other days running. There is not enough
You MUST have a correction factor for the day involved. That
means: barometer, vapor pressure,and accurate temperature at the
carburetor inlet. Without these you are just comparing the last
run with the one just made but not a reference to anything done
that morning or even later in the day. As the engine becomes more
heat sinked the power will change.....so...consecutive runs may
be actually better in power but give a lower or the same reading.
On an engine dyno the temperatures are controlled and thus you
can do a lot more work, and consecutive runs, with excellent accuracy.
Clutch and rear wheel slippage, gear frictional loss all count
to reduce the accuracy along with the temperature of the oil in
all those little moving and rotating items.
Wheel dynos are a good tuning tool, I used one a lot in the
far past, but as a scientific instrument for making comparisons
there is just too much lacking in information & accuracy.
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