Cars Need someone to help me fix a solid rear axle suspension on otherwise finished car (Glas Exo-Rod)

[AccAkut]

So some may have stumbled upon this already, a car I have been twiddling on for a while now.

It is more or less nearing release actually, but the physics for now have major issues, as it seems like the rear axle does something that makes the car unrecoverable once the rear slips, and I can't figure out what it is.

so if you KNOW what you're doing and don't just want to grab the car, please reply

 

[Stereo]

On the Monaco when I was setting up the rear axle, adding anti-squat for some reason made it bind up and effectively give it a bunch of anti-roll strength (detected by using telemetry app on 4 wheel loads, inside rear dropped faster than inside front), I fixed it by moving the chassis mount points farther from each other (so instead of 2 vertical where the front end of the leaf spring attaches, the bottom one's outward, top one's inward, like a 4 link) This reduced need for the lateral spring as well.

 

[Ghoults]

Try something basic. Try making a 3 link setup + panhard bar with these details:
- 2 longnitudinal bars on bottom near the tires + 1 on top in the middle. Make as wide as possible between the tires
- upper bar length is 2/3 of the lower bars
- bar attachment on axle: longnitudally on the middle of axle but vertically say 10cm below and above
- lower bars level when car is standing stationary
- upper bar points little bit towards ground (you have this the wrong way around, yours is pointing up) when car is stationary
- panhard bar should also be level when car is stationary. Put it 10cm behind the axle 5cm below axle center line and make it as wide as you can fit between tires. Move it higher you get more oversteer, move it lower and you get understeer.

Essentially with that setup it should look pretty similar from the side as a dwb setup looks from the front. Upper a-arm is shorter, arms closer to each other on the car side vertically and more apart on the axle/hub side and angles pretty similar but lengths little longer.

 

[AccAkut]

Try something basic. Try making a 3 link setup + panhard bar with these details:
- 2 longnitudinal bars on bottom near the tires + 1 on top in the middle. Make as wide as possible between the tires
- upper bar length is 2/3 of the lower bars
- bar attachment on axle: longnitudally on the middle of axle but vertically say 10cm below and above
- lower bars level when car is standing stationary
- upper bar points little bit towards ground (you have this the wrong way around, yours is pointing up) when car is stationary
- panhard bar should also be level when car is stationary. Put it 10cm behind the axle 5cm below axle center line and make it as wide as you can fit between tires. Move it higher you get more oversteer, move it lower and you get understeer.

Essentially with that setup it should look pretty similar from the side as a dwb setup looks from the front. Upper a-arm is shorter, arms closer to each other on the car side vertically and more apart on the axle/hub side and angles pretty similar but lengths little longer.

at the moment I have it like this, its following the model (or rather opposite) except upper arms

So you say I should try eliminating one of the upper arms and move the single one into the middle?

Currently length of the arms should be equal, so no binding of the rear axle while moving

 

[Stereo]

Upper and lower shouldn't be parallel, move the chassis mount point of the upper ones in or out + a little bit downward.

 

[Ghoults]

You can either go by making it 3 link or 4 link. You currently have 4link but your angles and lateral positions of your upper arms are a bit off. Looking at your 3d model you have a 4 link but your upper links should join in the middle in the chassis. I think that kind of setup is only used in offroad cars and trucks. I'd not go that route if you are not familiar with it.

So move your upper links laterally so they are directly above your lower links. Wider = better because less roll steer. I'm 99% sure roll steer is your issue. On the chassis side lower your upper link chassis mounts down say 3cm.

If you want to go 3link (which should be superior to 4link when it comes keeping your tires pointing forwards) just merge your upper links into one in the center and lower the chassis side of the upper arm a little. Say 3 centimeters. Lower links wider = better.

In ac in garage then adjust one side your rear suspension rideheight up and down and observe your toe values. While ac doesn't support toe in solid axles you can (iirc) still use the toe numbers to see where your rear axle is pointing (both tires have same toe value). With solid axles you are going to get rear steer everytime your rear axle is not level and I'd imagine this is cause your handling issues.

 

[AccAkut]

You can either go by making it 3 link or 4 link. You currently have 4link but your angles and lateral positions of your upper arms are a bit off. Looking at your 3d model you have a 4 link but your upper links should join in the middle in the chassis. I think that kind of setup is only used in offroad cars and trucks. I'd not go that route if you are not familiar with it.

So move your upper links laterally so they are directly above your lower links. Wider = better because less roll steer. I'm 99% sure roll steer is your issue. On the chassis side lower your upper link chassis mounts down say 3cm.

If you want to go 3link (which should be superior to 4link when it comes keeping your tires pointing forwards) just merge your upper links into one in the center and lower the chassis side of the upper arm a little. Say 3 centimeters. Lower links wider = better.

In ac in garage then adjust one side your rear suspension rideheight up and down and observe your toe values. While ac doesn't support toe in solid axles you can (iirc) still use the toe numbers to see where your rear axle is pointing (both tires have same toe value). With solid axles you are going to get rear steer everytime your rear axle is not level and I'd imagine this is cause your handling issues.

The 3D model is totally independent from the physical model, and I won't change it anymore, too much stuff on the same materials/textures that is now separated and bound with DIR_ stuff and so on. Looks cool anyway

I think going the 3-link route, without changes to the the Panhard bar did change the characteristic to the better a lot. Toe does not change if I play round in the setup menu like you suggested, always flickering +-0.001