Kunca8

13-04-2016, 09:59

Hi fellow sim-grinders!

I'm trying to find out what amount of engine torque is needed to spin the tires when accelerating in straight line.

So far I build very simplified equation counting with:

- Static weight distribution F:R

- Static aero downforce distribution F:R

- Roughly approximated curve of increasing downforce with speed

- Engine RPM at max torque

- Gearbox ratio - gear ratio x final gear ratio

- Tire grip - possibly falling with increasing speed (???)

I figured out quite low numbers of torque suspecting wrong tire grip input numbers:

- First thing is basic grip coefficient of racing tire on asphalt of a race track. So far I found 0,55 - 0,6 of ordinary tire on road which looks too low for racing conditions.

- Second is the falling grip with increasing speed - I found it in tire physics files of GTR2 and rFactor (nowhere else) as "SpeedEffects". It says at which speed (about 300 m/s) grip drops to half and how much (12 - 35 of what????) this affects grip with changing load. - I am quite lost here. Don't know how exactly use those numbers - at least the second one. Better description is here: http://z13.invisionfree.com/TougeLife/ar/t93.htm

So I want to ask what could be actual amount of basic grip and do I have to use "Speedeffect" - is it something from real life or it was made just for those two simulation games?

I'll be happy for any contributoin to this topic and pardon my bad English.

Thanks Kunca.

I'm trying to find out what amount of engine torque is needed to spin the tires when accelerating in straight line.

So far I build very simplified equation counting with:

- Static weight distribution F:R

- Static aero downforce distribution F:R

- Roughly approximated curve of increasing downforce with speed

- Engine RPM at max torque

- Gearbox ratio - gear ratio x final gear ratio

- Tire grip - possibly falling with increasing speed (???)

I figured out quite low numbers of torque suspecting wrong tire grip input numbers:

- First thing is basic grip coefficient of racing tire on asphalt of a race track. So far I found 0,55 - 0,6 of ordinary tire on road which looks too low for racing conditions.

- Second is the falling grip with increasing speed - I found it in tire physics files of GTR2 and rFactor (nowhere else) as "SpeedEffects". It says at which speed (about 300 m/s) grip drops to half and how much (12 - 35 of what????) this affects grip with changing load. - I am quite lost here. Don't know how exactly use those numbers - at least the second one. Better description is here: http://z13.invisionfree.com/TougeLife/ar/t93.htm

So I want to ask what could be actual amount of basic grip and do I have to use "Speedeffect" - is it something from real life or it was made just for those two simulation games?

I'll be happy for any contributoin to this topic and pardon my bad English.

Thanks Kunca.