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Rally 3 class

do u fellas think rally3 is good in nationals but kinda "meh" in erc? idk why... i hope Mille and Max goes direct to R5.
 
Sulland said:
The two current Rally3 manufacturers have made 200+ cars, so not bad.
But I feel we need som Junior stars, with some real personality, and Wrc and Erc need to give them airtime, both at and between rallies!!
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Sesks did not drive R3, but his growth via ERC is a road map for other young talents. ERC under the same promoter as WRC is a good thing for this sport.
 
I wish that it continues like this in Greece. Subarus and Mitsubishis are nice, but they are now in the past...
 
Armstrong and Fontana in development test in Portugal

https://www.facebook.com/share/p/1G4EsUJ7oa/?mibextid=wwXIfr

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BBman said:
They are consistently at around 2 seconds/km slower that Rally 2. Not sure if that is good or bad, but there is definetly room for another mm in restrictor size.
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Referring back to my comment from 2023, which was argued upon. At Rally di Roma Capitale, the leading Rally 3 was 2.9s/km from the winning RC2. Ok, not a top driver, but neither was the leading Rally 4 only 0.4s/km away.
It is obvious that tarmac is not a strong surface for the Rally 3. But it doesn't get much better on gravel. At Acropolis the difference between Solberg and Turkkan Ali was... 2.9s/km. Yet again, a particular rally and you cannot compare the two drivers, even if Turkkan is a very talented driver (imo). But even compared to Prokop, the difference is still over 2.1s/km.

The point I want to make is that the rallies where you have a Rally 3 under 2s/km vs Rally 2 are the exceptions.
I do not want to bash the class, but I do not believe that this was the intended performance gap, especially considering the cost.
 
Does FIA have any plans to change anything on the Rally3 class tech?

Maybe give the restrictor 1 more mm, to get the SS speed per km a bit closer to the Rally2 class?
 
Gordini said:
How much hp will you get with changing the restriction from 31 to 32 mm, and from 31 to 33 mm?
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Increasing the diameter of a 30 mm restrictor by 1 mm increases the area by 6,6 % and assuming a constant air to fuel ratio the power would also increase by 6,6 %

31 mm -> 32 mm = (32 * 32) / (31 * 31) = 1,0656 => 6,56 %
31 mm -> 33 mm = (33 * 33) / (31 * 31) = 1,1332 => 13,3 %
 
OldF said:
Increasing the diameter of a 30 mm restrictor by 1 mm increases the area by 6,6 % and assuming a constant air to fuel ratio the power would also increase by 6,6 %

31 mm -> 32 mm = (32 * 32) / (31 * 31) = 1,0656 => 6,56 %
31 mm -> 33 mm = (33 * 33) / (31 * 31) = 1,1332 => 13,3 %
Click to expand...
It's actually a bit more that that as you have to allow for the boundary layer of air next to the restictor wall that doesn't move as fast as the air in the middle.

If we assume the boundary layer is 1 mm thick (I'm only guessing here) then the change from 30 to 31 is actually (29*29)/(28*28) = 1.7027 ~ 7% &c &c.

If the boundary layer effect is more than 1 mm then the increase will be even more.
 
Thanks for the additional info. My calculations are purely theoretical. I don’t have any education in automative engineering or fluid dynamics.

It would be nice to know how close these theoretical calculations are to measured engine power in a dyno. I assume the measurements in dynos also would vary from dyno to dyno and ambient temperature and air pressure.

I think the power of the previous generation (1997 – 2010) wrc cars was close to 350 ps. Current rally2 cars I believe to have at least 300 ps so I made some calculations with a 32mm restrictor = 300 ps and a 34 mm restrictor = 350 ps.

32 mm / 300 ps as base: 34 mm / 350 ps as base:
32 mm 32 mm = 310
33 mm = 319 ps 33 mm = 330 ps
34 mm = 339 ps
35 mm = 359 ps 35 mm = 371 ps
36 mm = 380 ps 36 mm = 392 ps

32 mm 300 – 310 ps
33 mm 319 – 330 ps
34 mm 339 – 350 ps
35 mm 359 – 371 ps
36 mm 380 – 392 ps

Of course these three engines (wrc, rally2 and rally1) are also different

TGR’s web site says that current rally1 car with a 35 mm restrictor has over 370 ps.
https://toyotagazooracing.com/wrc/cars/2025/

Between Ford and Renault rally3 cars at least the official figures are big.

Ford 235 hp: https://www.m-sport.co.uk/_files/ugd/89553f_6e2a1c4bceaa4436b93535d4040bbf5f.pdf
Renault 260 hp: https://media.renault.com/clio-rally3-ready-to-conquer-the-world/
 
Have any of the two brands used any jokers in 2025?
if yes, what parts of the cars have been updated?
 
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