[WRC] Arctic Rally 2021

[Mirek]

I might not understand you correctly because of a bit of a language barrier but i don't think you are correct here. In the theoretical situation you mentioned where the peak power of the cars is same but some have a more flat powercurve and you dragrace them in perfect situations the car with the smoother curve will win. What it means is that the top speed of all cars is the same providing they are not limited by gearing (or are geared the same).
My logic is that the torque of the engine does not matter. What matters is the torque going to the wheels and that can be changed with gears. The amount of torque needed is limited by the grip of the tires so the cars that have a more acute power curve will be geared shorter so the torque in the wheels will be similar as the cars with a smoother power curve. If you have a better engine torque delivery it gives you much more freedom in the gearing and the ones with worse torque delivery need to optimize more. Where it will matter more is the type of stages where the cars will be near their top speed as neither the Ford or Hyundai have been physically limited by lack of power but rather by the rev limiter. So the lack of engine torque will be a bit less important in the more technical and slower rallies where the drivers will be on wide open throttle for shorter amounts of time.

This is a bit difficult because all scenarios are somewhat theoretical both mine and yours.

You are right that the important thing is torque on the wheels but that is why I give the example in speaking about power curve. Because the torque on the wheels x wheel speed is the same thing as the engine power minus mechanical losses, i.e. speaking about power curve simplifies things (when talking torque you anyway get from one power curve to another power curve but in a more complicated way).

You are also right that normally the teams will try to limit what they loose in the power band by using different gearing but they need a ballanced peformance, they need also certain top speed on straights, traction etc. In other words where one team can use shorter gearing to their advantage the other can do as well and keep their advantage (or put the advantage on top speed if needed).

Why it matters more on twisty stages (in my interpretation based also on long time observation) is because no matter how much time you push the throttle you always need to deliver biggest possible energy on the wheels in that period of time, i.e. largest possible graph area under the power curve. In twisty events it is physically impossible to keep the engine RPM tightly around the peak power and therefore car with flatter curve will always have advantage because between two gearshifting it always delivers more energy to the wheels.

The second reason why it matters more in lower speeds is traction because car with flatter curve has smoother delivery of the wheel torque (less raise or drop of torque).

IMHO this was very well illustrated in times when S2000 were the second category. They had very low torque compared to the turbo cars but reasonable power. They were able to keep within 1 s/km on very fast events (Finland for example) but the difference was around double on twistier mountain events (Acropolis for example) and even worse in muddy events (up to tripple sometimes).

You are right that normally the team with stronger engine may use advantage of the higher top speed but they also may opt for other options, for example higher downforce, hence why we can not know whose engine is more powerful just by looking on the onboards. We don't know how they ballanced the drag/downforce/power/torque/gearing/traction and how successful they were in their preparations.