GR Yaris Dyno graphs?

[Barry P.]

Two graphs, both from the same dyno with 5bhp difference in wheel hp but corrected engine power is 30 bhp difference. Can somebody familiar with operating dynos explain the big difference in corrected power?

 

[Onehp]

Both awd cars?

 

[Barry P.]

Yes, both same type of car

 

[Onehp]

The dyno measures the drag loss of the car when it is running out. Most probably the higher power car was strapped down harder, thus losing more power from the tyres on the rollers. This drag is then added on the wheel measured power resulting in engine power. This number in turn is corrected for temperature and perhaps also humidity etc.