C&S Evo7 said:
nice will,
im not at all familiar with hub dynos so some questions as it seems a little lower than i would have expected (only 10 or so hp)
- the max rpm seems low?
- the speed seems low? what gear was it in?
-what is the temp reading, IAT or coolant?
All data on the right hand side is telling you the variables from where the yellow cursor line is.
Air temp ambient was 41F, as for coolant temp, I waited until the fan tripped on then made sure the gearbox upto temp, when the fan switched off I comenced the run. Max rpm is 8400 so that it wouldnt HIT the limiter. Test was in 4th gear, not that it matters.
AS for the hub dynos/roller dynos and how they work... heres a basic explanation of the two.
Roller dynos have a pre-calibrated mass (of the roller(s)) in the software, it knows this, it measures the rate of acceleration and using newtons second law of motion (which is Force = Mass x Acceleration) it works out a force (torque). Then, by way of inductive RPM pickup or CALCULATE or TYPED or FOUND gear ratio it uses the
well known formula 'hp = rpm x torque / 5252 formula' to work out the hp.
Now the dynapack systems are essentially just digitally controlled hydraulic pump-heads where the fluid outlet/inlet can be electronically controlled. On these pump-heads amongst other technology there are calibrated digital pressure gauges in each dynapack pod. It literally DIRECTLY measures the torque at the axles then divides that by the overall drive ratio to have to engine torque after losses. It also works out the HP from this directly measured torque!.... you could argue theres no more accurate method.
Utilising SAE correction method, a power correction is applied to standardise the results to a 'standard day' which is why DYNAPACK is so repeatable any day of the year.
The 'TC' 1.00 is the total correction factor you can apply to graphs, like for instance if you put a TQ into honda and they came back telling you there was 15% drivetrain losses on a k20a engine then you could change that number to 1.15 to represent that. Theres so many different ways of working out/estimating engine HP that this is the only accurate way of showing it IF the information is available. Otherwise its much better to simply look at whp.