Cars 2016 Focus RS data (WIP) I have questions :)

[arthur666]

I think my strut front suspension is sorted. Pretty straight-forward. But I still need to tweak the rear. Feels ok with a rough estimate, but I've got some measurements and will get car back on lift and take more this week.
Real car is SLA/control blade independent rear axle. Turning it into an Assetto Corsa DWB is a bit more confusing to me than plugging in measurments and angles for a McPherson strut.

Should the bottom of my DWB setup look something like this?

 

[arthur666]

EDIT: Just noticed the "Dumb Questions" thread. I should ask there.

Which looks correct in this diagram?
Top or bottom?

Top has intersecting point between 2 outer pivots on real car. Bottom has the point at the rear outer pivot. Ignore the gray line representing travel path for now.

 

[Emery]

Of those two, the bottom pic is what I'd use as it is the interaction between the upper & lower A-arms that you're trying to capture.

Where does the control blade come into action? Is it only for the upper arm?

 

[arthur666]

Thanks. Bottom is what my gut told me to go with. The control blade is the upper front control arm, I guess. For that I'll just connect the dots from pivot to pivot.

 

[Kyuubeey]

Log your camber and toe curves from the geometry. Otherwise almost pointless to play around with it because you don't know what you need to do.

 

[arthur666]

How do you get those curves? I was working off the assumption that if you get all the main points in the right place, toe and camber changes will "fall into place." But I would appreciate getting educated because working on this car has been fun.

I'm having fits.
I have 2 questions

1. Which of these real parts correlate to the AC parts?

The real rear suspension consists of:
-Main rear lower arm
-Upper and lower control arms
-Control blade
-separate shocks and springs
-ARB

The AC DWB suspension is:
-upper wishbone
-lower wishbone
-steering rods??? (realized this has huge effect on toe curve)
-shocks/springs
-ARB is virtual

2. So how important is correct placement of the top control arms?
Seems like if your alignment, angel of wheel travel and spring(ratio)/damping rates are ok, the suspension will mimic the real thing as well as the game will allow.

For the top, I'm using a generic wishbone that's not really based on actual pivots. I've gotten the car to drive in a way that feels like the real thing. Actually pretty happy with it, but I would like to tweak it even more, just for fun and education.

 

[Kyuubeey]

Search online how to properly measure curves of suspension. Better to have someone show you.

As to why it's beneficial, well for the same reason I needed curves to produce:

You see the lower arm is separated into lateral link and traction arm coming out of the lateral link, which I found quite dramatically changes the curves, enough to be noticeable on the data compared to Mazda's own curve data.

I can't just put the balljoints on the wheel joint, then on the car joints, and expect it to work 100%. Similar things will happen with your geometry, because it's not a traditional DWB setup.

 

[arthur666]

Thanks Kyuubeey. I'm starting to grasp it. The pivot points on a multi link are going to be virtual.
I used to sell/ride mtn bikes, so I had a little reference for this idea, but didn't even think about it until reading your description :

 

[Kyuubeey]

Pivot points on basically any independent suspension with arms are virtual, but it just means you need to achieve those correctly. It doesn't happen from arm geometry only, but the difference between a one-axis joint vs a spherical joint for example. The FD uses joints with bias the curve in some direction AND has them mounted inside of other suspension components, so the final curve is a bit different from the virtual spherical joint model. So you gotta tweak it.

Logging curves from your geometry will give you an idea how would be best to tweak it, what you would want to sacrifice, if anything, to gain what.