It all begun last fall when a friend of mine asked me how much power does the WRC cars have but I couldn’t give him any exact figures. I had heard / read about 330 hp but I wasn’t satisfied with that so I started to search for some answers. I found this web site http://www.kosunenracing.com/turbo.html and http://www.kosunenracing.com/ga.html (unfortunately only in Finnish) where they tell that 330–360 hp (with a 34 mm restrictor) have been measured from Group A Mitsubishis in Finland and the WRC cars are estimated to have 350-380 hp and torque between 650-750 Nm.

When I visited SWRT’s web site I got really curious because they say that the Subaru has a torque of 700 Nm @ 4000 rpm. That would mean that the power @ 4000 rpm would be 399 hp (P (hp) = T (Nm) * revs (rpm) * 0,0001424 -> 700 Nm * 4000 rpm * 0,0001424 = 398,7) and the power peak is on higher revs than the torque peak, so peak power for Subaru must be over 400 hp.
http://www.swrt.com/the_team/the_team.html (The car / Technical specification)

On Jussi Välimäki’s web site I found more information. The car (Mitsubishi Evo 8) he’s driving in the Finnish championship is the same car with which he won the Asian-Pacific championship in 2005. It has been modified to a Grp A car and the figures for the car are: Peak power (Maksimi teho): 350 hp @ 4800 rpm and peak torque (Maksimi vääntö): 650 Nm @ 3500 rpm. I don’t think these figures are any estimates because AMW Dyno Service is the other one of the two companies who takes care of the maintenance of the car. Putting the car in a dyno is probably the only way to find out what have been achieved with the tuning of an engine and the effect of the adjustments.
http://www.jussivalimaki.com/ (Mitsubishi Lancer)

I decided to put the figures in Excel and make some power calculations and finally graphs of the results. The torque figures (540–600 Nm) I found for other cars weren’t even close the one of Subaru so I used for Subaru also a lower torque I found in a magazine. As a base (or model) for the torque curves I used an estimate curve for WRC cars from a magazine (VM 1/2007).

http://i267.photobucket.com/albums/i...rque_graph.jpg

And the same as an Excel graph:

http://i267.photobucket.com/albums/i...2000_graph.jpg

The figures I used to begin with are:

Ford: 550 Nm @ 4000 rpm & 300 hp @ 6000 rpm
Citroen: 570 Nm @ 2750 rpm & 320 hp @ 5500 rpm (I put the torque peak @ 2800 rpm)
Subaru: 590 Nm @ 3500 rpm & 300 hp @ 5000 rpm
Skoda: 600 Nm @ 3500 rpm & 300 hp @ 5500 rpm
Peugeot: 580 Nm @ 3500 rpm & 300 hp @ 5250 rpm (I put the ”power peak” @ 5300 rpm)
Mitsubishi: 540 Nm @ 3500 rpm & 300 hp @ 5500 rpm
Suzuki: 590 Nm @ 3500 rpm & 320 hp @ 4500 rpm

After copying the estimate graph for every car, I put two points in the graph, the peak torque and the calculated torque at the revs where the power is 300 hp (320 hp for Citroen). For example for Ford the two points are 550 Nm @ 4000 and 351 Nm @ 6000 rpm (T = P / (revs * 0,0001424) -> 300 / (6000 * 0,0001424) = 351 Nm). After that I adjusted the curves to rise and decline smoothly.

And here are the results for “torque low” and “power low”:

Torque: http://i267.photobucket.com/albums/i...torque_low.jpg

As you can see the Citroen’s curve start to increase at low revs and the Ford’s at higher revs. In this graph Jussi Välimäki’s grp A Mitsubishi has the highest torque except for the WRC graph that is an estimate.

Power: http://i267.photobucket.com/albums/i..._power_low.jpg

Because of the early increase of the torque curve, Citroen has the highest power between revs 1800-2900 rpm. In the middle revs (3000-5200 rpm) the power is little lower than for the other ones but is again second best of the WRC cars beyond 5200 rpm. In the same magazine (TM 14/2005), from where I picked some of the figures, Juuso Pykälistö told: “The engine of the Citroen is a rev engine. It has a broad rev band, the gear shifts takes place far beyond 6000 rpm and at lower revs it’s not so powerful compared to the Peugeot. On the other hand the Peugeot’s rev band ends just after 5000 rpm”. Ford has the highest power beyond 4500 rpm. Still Mikko Hirvonen tells in the same magazine that: “The Ford can be safely driven with high gears and low revs”. These two comments are a little bit of mystery for me but I’m neither an engineer nor a rally driver. Subaru’s power starts to decline quite rapidly after 4700 rpm. Mitsubishi doesn’t have so high power but the curve is quite flat (easy to drive?) and is third best beyond 5600 rpm.

The next task was to put some more torque so I just added 110 Nm the whole way. I picked the 110 Nm from Subaru’s two different torque values 700 Nm and 590 Nm, which I used in the beginning.

Torque: http://i267.photobucket.com/albums/i...orque_high.jpg

Power: http://i267.photobucket.com/albums/i...power_high.jpg

Ford has the highest power, 431 hp @ 5000 rpm and Mitsubishi has the lowest power, 387 hp @ 5300 rpm.

The following ones I made by keeping the same torque as in the “high” graph but lowering the torque so as the curve goes true the point where the power is 300 hp (again 320 hp for Citroen). So these are a mixture of the two previous ones.

Torque: http://i267.photobucket.com/albums/i...que_medium.jpg

Here the curve of the Mitsubishi and Citroen are side by side after the torque peak. For the other ones it seems that the curve is declining a little bit to fast.

Power: http://i267.photobucket.com/albums/i...wer_medium.jpg

Suzuki’s power is declining fast with this option and Citroen would have only 337 hp.

And here are graphs by make.

Ford: http://i267.photobucket.com/albums/i...rque_power.jpg

Citroen: http://i267.photobucket.com/albums/i...rque_power.jpg

Subaru: http://i267.photobucket.com/albums/i...rque_power.jpg

Subaru SWRT: http://i267.photobucket.com/albums/i...rque_power.jpg

In the SWRT graph I put the “medium” and “high” from the previous and the figures from the web site. As you can see, the result for 700 Nm @ 4000 rpm will generate a peak power of 413 hp @ 4300 rpm which is higher than for the “high” option, 404 hp @ 4500 rpm.

Skoda: http://i267.photobucket.com/albums/i...rque_power.jpg

Peugeot: http://i267.photobucket.com/albums/i...rque_power.jpg

Mitsubishi: http://i267.photobucket.com/albums/i...rque_power.jpg

Mitsubishi Grp A: http://i267.photobucket.com/albums/i...rque_power.jpg

Suzuki: http://i267.photobucket.com/albums/i...rque_power.jpg

I found also some different figures for the Suzuki at Sebastian Lindholm’s web site http://www.sebateam.fi/

Suzuki SL: http://i267.photobucket.com/albums/i...rque_power.jpg