GR Yaris GR-Yaris Rally2

Florens said:
It might actually be the 3 cylinder - didn't they push for a change in regulations to allow for use of a 3 cylinder engine vs. the default choice of a 4 cylinder engine?
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Yeah, rules say up to 4 cylinders and three cylinder engines get to run slightly higher valve lift.

Hope it's three pot.
 
Michael Knight said:
Rally2 technical regulations. 3 Potter can have 13mm of lift vs. 11mm for 4cyl
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Interesting and quite logical as there are only 12 valves vs 16 on a 4-pot
16x11=176
12x13=156

As a measure for the amount of air that can pass, however a 3-cyl will have bigger bore allowing larger valves. E.g. Ford FST 4-cyl is 79mm, GRY is 87,5mm. If valves are equally larger, the flow factor area is then (87,5/79)²= 1,22

156x1,22 = 191

I'm guessing the valves aren't linearly larger to the bore, or otherwise the 3-pot might have some advantage, although there is a 32mm restrictor for all so that probably levels things off from the get go....
 
Differences between AP4 and Rally2. With quick overlook Rally2 seems to be rather close with AP4, other uses Homologation parts whereas AP4 has had more free spec for instance for Engine components -> good testbed for Rally2 Homologation..?

Rally2AP4
Minimum /competition weight (kg)
1230/1390kg1230/1390kg
Engine parts (pistons, Connecting rods, crank, etc)Original or homologatedFree with limitations to rulebook
Cylinder Head and Compression ratioHomologated part. 10.5:1
Only original part allowed.
The gasket face (plane) may be re-surfaced by a maximum of 1 mm (for adjusting the compression ratio)
Valve lift11mm 4 cyl / 13mm 3 cyl11mm 4 cyl / 13mm less than 4 cyl
Intake & exhaust valve sizesOriginal or homologatedOriginal size
Gearbox5 speed6 speed
Turbo & Boost2.5bar absolute, with 32mm restrictor2.5bar absolute, with 34mm restrictor
Gearbox5 speed (?), homologated6 speed, from known manufacturer
DiffsHomologated, MechanicalSeries centre diff can be used, but active center diff is not allowed
 
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If the schedules hold (they're due to change in Rally Japan it seems) - we might see the first outing of Gr Yaris Rally2 Car tomorrow morning at 8:35 Finnish time meaning 6:35 UK time?
Hope Kankkunen is in mood for a proper go, and hope we would get live feed and WRC+ Commentator co-driving as we got from Secto Rally Finland from the GR Yaris 2021.
Fun times ahead!
 
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Onehp said:
Interesting and quite logical as there are only 12 valves vs 16 on a 4-pot
16x11=176
12x13=156

As a measure for the amount of air that can pass, however a 3-cyl will have bigger bore allowing larger valves. E.g. Ford FST 4-cyl is 79mm, GRY is 87,5mm. If valves are equally larger, the flow factor area is then (87,5/79)²= 1,22

156x1,22 = 191

I'm guessing the valves aren't linearly larger to the bore, or otherwise the 3-pot might have some advantage, although there is a 32mm restrictor for all so that probably levels things off from the get go....
Click to expand...
Bigger valves & lift could help it having better torque as restrictor limits top end power? interesting nevertheless, to see different approaches.
 
Michael Knight said:
Bigger valves & lift could help it having better torque as restrictor limits top end power? interesting nevertheless, to see different approaches.
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Correct. While the restictor is a limit on absolute power, valve lift may limit power per revolution, that is, torque.
 
first foto seen of Rally2 car?
Nice beefy fenders
1668235765795.png
 
maybe you can buy that hood then from TGR directly - fun to see if that's true and what's the price. For some items for example Porsche racing division has much lower prices than consumer side, hope its the same with GR Yaris Rally2.
 
Michael Knight said:
maybe you can buy that hood then from TGR directly - fun to see if that's true and what's the price. For some items for example Porsche racing division has much lower prices than consumer side, hope its the same with GR Yaris Rally2.
Click to expand...
I'd buy one in a heartbeat.
 
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