Hi Guy,
I wonder if you can share your wisdom on this.
I can not find information on how the change of a final drive changes the RR figures (if at all). I researched this topic on google but can't really find any good source of information.
Can you take time out to give me your opinion.
thank you
sean
Effect of final drive and gear ratios on dyno output
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Effect of final drive and gear ratios on dyno output
205 8v Track car
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Hi,
From my experience there is no change in dyno results caused by wheel size, gear ratio or final ratio, if dyno run is made on gear that provide enough load and enough logged data points.
E.g two dyno runs on different wheels (winter and summer, different sizes) gives usually identical results. Also dyno runs, made on 4th and 5th gear, gives the same figures (on naturally aspirated cars). On turbo cars the situation is different because of different load, which cause faster or slower boost rise (of course this apply only to inertia dyno)
Everything I wrote above apply to 'engine power' measurements. When measuring only 'power on wheels' there will be difference, caused by different rolling friction losses, which are dependent on vehicle speed, which is different on different gear/final drive ratio.
ohv
From my experience there is no change in dyno results caused by wheel size, gear ratio or final ratio, if dyno run is made on gear that provide enough load and enough logged data points.
E.g two dyno runs on different wheels (winter and summer, different sizes) gives usually identical results. Also dyno runs, made on 4th and 5th gear, gives the same figures (on naturally aspirated cars). On turbo cars the situation is different because of different load, which cause faster or slower boost rise (of course this apply only to inertia dyno)
Everything I wrote above apply to 'engine power' measurements. When measuring only 'power on wheels' there will be difference, caused by different rolling friction losses, which are dependent on vehicle speed, which is different on different gear/final drive ratio.
ohv
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