So on here when we post up numbers do we go by the Mustang Dyno rule of thumb or by the Dynojet rule of thumb. . . becuase that can be a big difference in numbers. . . .

 

BY "rule of thumb" do you mean correction factors so as to somehow normalise the numbers?[/align][/align]My experience and observationhas been as follows:[/align]
[ul][*]any loaded roller input braking dyno (hydraulic. eddy-current, or otherwise) will produce numbers that are 5% to 10% higher than an inertial dyno (I'll use 7.5% below);[*]braking dynos that do not use rollers (I.e. those that connect directly to the hubs) will produce numbers that are 10% to 20% higher than an inertialunit (I'll use 15% below);[*]drive train inefficiencies (generally estimated and used to "correct" rear-wheel numbers to flywheel HP) are typically 12% to 15% for manual transmissions and a couple points higher for autos.[/ul]
Inertial dynos are generally considered to be the most accurate (in terms of consistency with real-world performance ) of the lot--so, I would propose that one would first correct the braking dyno numbers to inertial dyno equivalency:[/align]
[ul][*]roller type braking dyno #s* 0.93 = inertial dyno equivalent;[*]hub type braking dyno #s * 0.87 = inertial dyno equivalent;[/ul]
and then solve for flywheel HP/torque;[/align]
[ul][*]inertia dyno #s (actual or corrected as above) * 1.15 = flywheel HP/torque...[/ul]
Or, just report the actual numbers and include the type of dynamometer used--which seems to be what most folks do...[/align][/align]

 

Sweet. Thank you.