Technical Analysis: WRC Cars 2017

[Mirek]

The peak torque of Fiesta R5 on the graph is likely higher than I remembered - 420-430 Nm is probably more realistic.

[NickRally]

I would say the combination of the two numbers still looks plausible to me:

p-curve 3.jpg

Though I agree they would most likely be slightly off the mark for the new WRC cars as absolute numbers.

[br21]

I would say the combination of the two numbers still looks plausible to me:

p-curve 3.jpg

Though I agree they would most likely be slightly off the mark for the new WRC cars as absolute numbers.

With restrictor those graphs look much different, like Mirek wrote - torque is falling down rapidly after it's peak

[NickRally]

br21 – the torque in both graphs, Mirek’s and the second of my graphs, is falling pretty equally down. According to Mirek, the peak torque value in his graph (there are no Y axis values to derive from the graph) is ~425Nm, while the max power is 300hp, which looking at the X axis, happens to be at 5750rpm, that means 366Nm of torque, so the difference in torque values between max torque and torque at max power is ~59Nm. Now going back to my graph, the max torque is 450Nm and the torque at max power is ~391Nm (assuming max power at 6840rpm to preserve the same velocity in the air restrictor when switching from 33mm to 36mm), so the difference in my graph is 59Nm – not different to Mirek’s graph.

[br21]

reality is torque at 6500rpms in R5 is close to 300Nm, not to 400Nm...

[NickRally]

What size air restrictor is this with?

[OldF]

What size air restrictor is this with?

32 mm

[OldF]

NickRally,

I think Mirek and br21 mean that the torque is not as flat as in your second graph having level torque from 1500 rpm to about 4500 rpm. Below is a dyno graph for a Mitsubishi EVO 9 group N (32 mm restrictor). Not the best example either because these cars had more boost compared to the current ones (max 2,5 bar absolute).

[NickRally]

Thanks OldF. So simple extrapolation from 32mm to 36mm (2017 WRC), would turn the 300Nm into 380Nm for R5 car. Once again, my calcs above do not seem unreasonable. And in any case nobody seems to dispute the 380hp max power for the 2017 WRC cars, which appears to be achieved at around 6500-7000rpm, which in turn using simple maths, translates into 411Nm of torque if the quoted max power was at 6500rpm or 382Nm of torque if quoted max power was at 7000rpm.

[NickRally]

Flatness of my graph - as I pointed out this was identical to Mirek's graph.