WRC engines

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manchild
22
Joined: Fri Jun 03, 2005 9:54 am

WRC engines

Post by manchild » Tue Dec 20, 2005 1:44 pm

Does anyone has info (realistic not official) about power of modern WRC engines. I mean, they all say 300 hp which is stupid because one engine for WRC car that lasts 1000 km costs more than whole Subaru Impreza road version which has also 300 hp.

So, if engine for competition car must be based on road version and having in mind that engine for competition costs more than 100.000 euros and lasts only 1000 km I ask how much horse power it has.

I’d say 500 +/- 50 but that is just a wild guess.

RH1300S
1
Joined: Mon Jun 06, 2005 2:29 pm

Post by RH1300S » Tue Dec 20, 2005 2:15 pm

I can't answer your question directly, but instead of horsepower (which has a notional limit) - the torque curve is immense and very flat, so they have more power more of the time.

Here are some numbers for a Ford Focus WRC 2003 Version

Performance

Torque / rpm
550 Nm @ 4000

Power / rpm
300+ bhp @ 6500

Transmission
6-speed 4WD

Weight
1230 kg

0-100km/h (tarmac)
3.2 s

Peugeot 206 WRC

Performance

Torque / rpm
535 Nm @ 3500

Power / rpm
300+ bhp @ 5250

Transmission
6-speed 4WD

Weight
1230 kg

0-100km/h (tarmac)
3.0 s

manchild
22
Joined: Fri Jun 03, 2005 9:54 am

Post by manchild » Tue Dec 20, 2005 2:34 pm

That + seams to be "the great unknown" :wink:

sion_williams
0
Joined: Thu Dec 08, 2005 6:12 pm

Post by sion_williams » Tue Dec 20, 2005 4:05 pm

I think they are only limited due to the restrictors in the turbo. I think the ballpark figure is 540BHp but that is a guess!
I mean, they all say 300 hp which is stupid because one engine for WRC car that lasts 1000 km costs more than whole Subaru Impreza road version which has also 300 hp.
A WRC engine has to be reliable enough to be driven to each stage, not only this but its more so the tourqe that is whats majorly different. You can see with that Focus above produces 535Nm torque!

RH1300S
1
Joined: Mon Jun 06, 2005 2:29 pm

Post by RH1300S » Tue Dec 20, 2005 4:32 pm

I can't say for sure what horspower levels they achieve, but there is a 34mm restrictor rule. That has to limit ulitimate horsepower even with a turbo - at some point you just won't be able to force enough air in whatever you do.

I bet the 300bhp limit is pretty close to reality. But, they are getting a lot of that 300bhp much further down the rev range than they would with a N/A engine.

They spend a lot of that money reducing engine friction & weight (as far as regs allow), increasing compression ratio and reducing lag.

sion_williams
0
Joined: Thu Dec 08, 2005 6:12 pm

Post by sion_williams » Tue Dec 20, 2005 7:35 pm

If you look at the power curve of a WRC car they hit 300BHp at about 2K RPM, with the restrictors it then holds that right through the range, for it to get 300BHP at 2k it must have more power in reserve for the rest of the rev range

Guest
0

Post by Guest » Tue Dec 20, 2005 10:12 pm

Why cant it peak at 2k rpm ? If they cant push more into the engine than at 2000 rpm then the power wouldnt increase with rpm.

My field of expertise is in software but doesnt it seem logical ?

/ Fx

Guest
0

Post by Guest » Tue Dec 20, 2005 11:43 pm

More air that is.

/ Fx

RH1300S
1
Joined: Mon Jun 06, 2005 2:29 pm

Post by RH1300S » Wed Dec 21, 2005 11:05 am

Anonymous wrote:Why cant it peak at 2k rpm ? If they cant push more into the engine than at 2000 rpm then the power wouldnt increase with rpm.

My field of expertise is in software but doesnt it seem logical ?

/ Fx
Exactly - the engine is restricted by the amount of air it can take in, so limited in how much it can burn. The torque curve would be nothing like the same shape as a N/A engine. By letting the engine rev more (even if it is not making more power), they give the gearbox a chance to propell the car along at a decent pace.

Reca
137
Joined: Sun Dec 21, 2003 5:22 pm
Location: Monza, Italy

Post by Reca » Fri Dec 23, 2005 12:06 pm

Avoiding the details of the calculation and assuming standard pressure and temp with a 34 mm restrictor the max mass flow is about 0.22 kg/s; let’s say A/F = 14 hence 0.22 / 14 = 15.7 10–3 kg/s fuel.
Energy per unit mass of fuel (the heating value) is about 47-48 MJ, and the engine efficiency is usually about 32-33%, hence as first order approximation we can reasonably hope to extract something in the order of 15.7 * 48 * 0.33 = 248 kW, make it 250 kW = 335 hp.
Based on that calculation and given that very likely max power isn’t the main concern in the application, I would say that probably best engines are between 320 and 330 hp.

But I would also add that there’s probably a not small difference between the best ones and the others, both on peak power and, mainly, in power distribution on the rpm range; at the recent Monza Rally Rossi was driving an official Prodrive Impreza and even from the grandstand the engine difference with the Fabia driven by Capello and McRae, official too, was very evident, that blue car is simply a rocket.
And that without considering the difference with the older and private cars, I’ve seen Rossi passing a couple of 2003 206 WRC in less than 200 m after a slow speed corner, and notice that Rossi was visibly slower in the corner and opened gas later... God knows what that Impreza would have done in the hands of a good driver. Certainly it wouldn’t have been beaten by Capello’s Fabia.

Anyway the really amazing thing of the WRC cars is that even with such “low” power, they would leave easily any 500 hp Group B way behind in just few hundreds meters of a stage... It’s when you look at these things that you see the incredible difference 20 years made.
sion_williams wrote: If you look at the power curve of a WRC car they hit 300BHp at about 2K RPM,
That would require torque to be more than 1000 Nm, and clearly it can’t be. To find an engine with a torque of 1000+ Nm you have to look at the new Audi R10, and that’s a 5.5l twin turbo diesel.

Guest
0

Post by Guest » Mon Jan 30, 2006 5:42 pm

i really sincerely doubt that a wrc car would leave for instance a audi s1, with a 600+hp engine and a weight of about 800kg

Guest
0

Post by Guest » Mon Jan 30, 2006 6:52 pm

http://www.rallycars.com/Cars/Cars_Background2.html

To give you an idea of the kind of performance GroupB cars were capable of I'll mention that in the 1986 season Henri Toivonen made two laps around the Estoril circuit, during a stage of the Portuguese rally, the fastest of which, in 1 minute and 18,1 seconds, would have qualified him in the sixth position of the F1 Grand Prix that same season. Ayrton Senna had the Pole Position in the 1986 Portuguese Grand Prix in 1 minute and 16,7 seconds...Toivonen was using the Lancia Delta S4 and was accompanied by his usual co-driver Sergio Cresto.

:shock: :shock: :shock:

Reca
137
Joined: Sun Dec 21, 2003 5:22 pm
Location: Monza, Italy

Post by Reca » Tue Jan 31, 2006 2:43 pm

Guest wrote: i really sincerely doubt that a wrc car would leave for instance a audi s1, with a 600+hp engine and a weight of about 800kg
On straight line acceleration, sure, a Group B would beat a modern WRC, but you can bet that on a stage the WRC is lot faster because in corners the Group B were very slow (in modern terms). Actually in some not particularly fast stages even a current Group N could possibly be a match for a Group B.
Guest wrote: http://www.rallycars.com/Cars/Cars_Background2.html

To give you an idea of the kind of performance GroupB cars were capable of I'll mention that in the 1986 season Henri Toivonen made two laps around the Estoril circuit, during a stage of the Portuguese rally, the fastest of which, in 1 minute and 18,1 seconds, would have qualified him in the sixth position of the F1 Grand Prix that same season. Ayrton Senna had the Pole Position in the 1986 Portuguese Grand Prix in 1 minute and 16,7 seconds...Toivonen was using the Lancia Delta S4 and was accompanied by his usual co-driver Sergio Cresto.
That’s pure rubbish and it’s a shame that it’s so often repeated on the web.
Do you really believe that Toivonen on a S4 would have been just 1.5s slower than Senna on a F1 in qualifying trim, considering the S4 had lot less power, 400 kg more, basically no downforce and rally tarmac tyres vs qualifying f1 tyres ? Then you have a quite low opinion of Senna...
Just consider that that time corresponds to an average speed of roughly 200 km/h and that for Group B cars that was quite close to the top speed.
The fact is that Estoril at the time had different courses, the F1 lap was 4.3 km and then there were at least 2 shorter courses about 2-2.5 km long and cutting the inner, slower part; assuming that the 1’18”1 is a reliable info (and it wasn’t for example 2’18”...), Toivonen certainly didn’t use the full track but one of the shorter courses, the average speed in the order of 100 km/h is definitively more believable.
Very likely somewhere on the chain of the memory someone compared the time with the F1 forgetting (voluntarily or not) the “insignificant” detail of the track used and made up that idiocy of the 6th time on the grid. Then internet did the rest distributing the idiocy on the whole world.

manchild
22
Joined: Fri Jun 03, 2005 9:54 am

Post by manchild » Tue Jan 31, 2006 8:17 pm

I heard about that too and was amazed but still in doubt having in mind F1 performance. Perhaps Toivonen was using full track lenght on dry day and perhaps F1 qualifying that year was under the rain?

Guest
0

Post by Guest » Wed Feb 01, 2006 10:44 am

on what grounds is a modern wrc car better at cornering? the b groups had unrestricted technology, when today everything is restricted. ofcourse things such as engine management and four wheel drive have evolved, but not enought to make up for over 400kgs of mass and all the aero devices, including skirts, which many of the cars(at least audi and lancia) had. cars havnt changed that much, the 83(not quite positive on the year) audi sport quattro2.2t beat the new mitsubishi evo9 on dry tarmac, on track. recently.