whp vs enginehp and losses
What are peoples thoughts about whp in different gears compared to enginehp
I can get the same whp in 3. Gear and 4. Gear.
- But engine hp is different.when the losses is calculated in.
- Are my settings wrong?
- Or is the losses to the fan in the eddy brake the factor that im missing
- Best regards
In the red curve i drove around 245km/t
I did place the dyno on the floor in the garage then placed the car on a hoist.
And when i reached topspeed i lifted the car off.
So i that way the curve is the loss from only the rollers and especialy the eddy current brake
The car is a ford fiesta 1.5diesel around 85hk.
In the losses test i ran inertia only.
So the loss measurement is not depending on the loadcell only retardation from the loss of speed.
During that run i was only driving the car upwards in a slow pace..... was afraid of driving of the rollers🙂
On inertia run its the same whp is the same in 3 and 4 gear.
The losses increase at higher rpm.
And i think its from that the hp is different.
In every gear
Two main things to consider here (assuming no slip and things like that):
- Losses are different at different speed. This is compensated for in the case you test for Engine power, but not Wheel power. For this reason, Engine power will compare better than Wheel power. But the compensation is using coast down losses, which are also somewhat different from full power losses, and speed dependent, so it will not be exactly the same
- The total MOI is slightly different between gears, due to the flywheel/engine having different speed with the same roller speed in different gears. You can measure the MOI in each gear and test again to see the effect of that
The drag in the brake and other internal dyno parts are part of the losses which are compensated for in Engine power numbers. There is a new function underway where you can specify these losses, see attached screenshot. This will remove that component of the loss for Wheel power, however, the losses in the tires and drive train are still uncompensated for in Wheel power numbers, so they will not be the same from one gear to the next.