“ are rfactor2 physics broken” video

Try GTE car, it is more important to test this on official dlc car than any other car.
I understand the consequences of arb changes just to be clear.
What i don't like is how i can balance significant loss of rear wing aero by just detached rear ARB.

 

We need something that can output concrete data. I'll try to find a way to use the porsche gte as I have been using it for the gte winter series so I'm familiar with it
About wing vs arb thing: I've always felt like the "kind of grip" provided by those two have different feeling, and that I can make the car rotate more with stiffer arb / springs while keeping the rear more planted and being able to put power down earlier and more abruptly with higher wing. I do have to test it tho as I see this "detach arb" thing repeated over and over.

 

is it possible to test how ARB affects alignments in gte cars ?

 

AFAIK only locked channels are engine related and downforce related, so it should be possible

 

If possible do check that. If it works as intended then ARB is not as useless as i thought.

 

@Bruno Gil I got an idea, since downforce is locked in motec what if we can check how ARB affects ride height in roll ? wouldn't that give us good evidence of ARB working ?

 

Hey. Who knows how packers work in rfactor 2

 

Good idea. Less left-right variation with higher arb would be the intended outcome. I'll check that

AFAIK they act as a bumpstop at the top of your suspension travel, limiting this

 

Nice, we are isolating the issues. i have few predictions already. if this works out we narrowed down physics issue to tire and then maybe some aero tweaks to punish low wing , excessive yaw allowance etc.

 

When I increase the packers, the ride height also increases.

 

In reality they are solid plates you put behind the bumpstopper (rubber), to reduce the suspension travel more like said.
For GT cars, the effects seems to be based on rideheight. 20mm Packer shift the bumpstop begin to higher ride heights by 20mm.
Note that the cars have different bumpstop begin even for packer 0. I made a shot about a c7 being pretty off in this area yesterday here.
Of course as they limit rideheight you might see a change in rideheight during a lap, but not standing in the box except maybe C7 which is off as I said allready

The LMP and DPI the effect is not working correctly, I made a bug report once. If you set a ride height of 60,70mm you can set 30mm packer, no effect and you touch ground if your springs are too soft. If you lower rideheight to 40, 50mm (no other change), the bumpstop shows effect and you dont touch ground. S397 copies bugs from one to the other car, sadly. So you have 2 choices, go really low and go around corners on the bumpstop or go really high in the Protos lol

 

color - stiff arb, white - soft arb

 

In C8R, when I ride height 60 mm and packers 35 mm, ride height in motec = 59 mm. And if packers are 40 mm, ride height in motec = 65 mm

 

As I said, 0 Packer does not mean that you hit bumpstop at rideheight 0. That depends on model parameters of the car we can not see.
If you hit it at 25mm RH for packer 0 , and you add 40mm Packer, you would force your suspension to 65mm even out of the box. Might explain it.
I just run a test with default setup, V= 0, changing rear to 60mm RH too. From default packer to 35mm packer both, nothing happens. From 35mm to 40mm Packer the front stiffness increases to 380mm/N and rideheight increases by 3mm. A clear sign that you lift your car by your bumpstopper allready at V= 0. Your available free suspension travel at front is null...
The rear shows no reaction so far

edit: the inverse logic is that your front suspension will hit bumptstop at ~20mm RH for Packer 0 approx. So if you run a track lap and you go below 20mm front RH (again: for Packer 0), you know you might run in the bumpstop with increased stiffness. That can cause understeer and tire wear, but also stabillity in some cases

 

The ACС is simpler and graphically clear. And here it turns out that without the motec, the suspension cannot be adjusted correctly.

 

Nice finding Stefan!
So therefor the bumpstop itself must have a height around 25mm, which make sense of course, as packers are basically only the spacers to adjust bumpstop height. How could you determine this "front stiffness increases to 380mm/N"?

Would be nice to have some sort of "suspension travel left" value shown at the setup page then.

I did a quick look into "skipbarber.hdv" example file, but coudn't found any specific sort of "BumpStopHeight" value. Maybe it's been done with "BumpTravel" and "BumpStopTravels".

 

I dont think that bumpstop have a "height". A stiffness constant that takes over yes, but not a final limit. I think they are an infinite large spring actually. You don´t have a superhard final end contact like in reality-
This allows us easily to climb up some 100mm curps / rims on street tracks at super high speed without breaking our suspension or flying off

 

Bunpstop stiffnes (BumpStopSpring), as well as progression of spring rate (BumpStopRisingSpring) are both part of a ".hdv" file.

 

I know what you mean and I'm not far from thinking like you, but I'm still struggling to find an objective way to highlight it. Without objectivity, it is only one opinion among many, and therefore useless.

I look at telemetry, I compare it with other simulators but I see nothing conclusive, at least nothing that proves that it is not normal or abusive.

I would like to have MOTEC data from real GT3s to compare but I don't know where to get it, assuming it even exists on the web...

All I can say is that indeed, I find it a bit too easy to do but I clearly don't find it efficient, I'm much more efficient if I follow the ideal trajectory correctly.

 

Changing only one axle is not abnormal in fact, it is even often used with the Porsche for example because of its short wheelbase and the flexibility of its chassis. Preventing the front axle from rolling allows to stabilize the rear for example.