Prototype Hydraulic Dyno Question

wildcat23

Member
How many teeth on the clutch sprocket and the rear axle sprocket do I need in order to dyno akra clones and modified clones? I am pretty sure the number of teeth on the clutch sprocket decreases when dynoing a modified engine. If anyone has this information from the original instructions and would post what gears I need I would appreciate it. I realize the instructions were wrote for flatheads but that shouldn't matter. Thanks!
 

alvin l nunley

Premium User
When I 1st bought my water break dyno, from Go Power dyno's, it came with a chart that showed you how fast the absorption unit had to be Spinney to hold X amount of torque. The absorption unit was capable of accurate readings up to 120 hp. I never ran a 4 cycle on that dyno, only 2 cycles, with RPM ranges of; low 8000, high 15,000. All the 2 cycles I tested had an RPM range of about 4000 to 5000 RPM. I never changed the gear ratio. Whatever the RPM is at the point the engine produces peak torque, the absorption unit has to be Spinney at the RPM where it is capable of holding that load. Once you get the dyno to spinning at that RPM, I see no reason to change the gear.
Do you have data acquisition software? Did it come with a computer? If not, do you have software to calculate HP from the torque readings? What about charts?
27 dyno chart.jpg
 
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