horizenjob wrote:
On Car9 I decided to use trailing arms that were level and about parallel. They are also longer. I don't understand your comment above about moving the link. Just like your other suspension arms you don't want short instant centers. Especially when you'are adding more travel to the suspension.
Another two ways to look at this. The most basic is that you can measure or double check this by seeing how much the hub moves forward and backward as it it move up and down. That's not really such a great thing. Imagine having to change the length of the wheelbase of the car when you tilt the car ( squat, dive, lift etc. ). This is why the suspension feels like it's not really working. With anti squat you need to move ( lift against the car against it's inertia ) the car forward a bit in order to get it to squat because the hubs move backwards as they rise upwards.
It's also similar to how you design for cornering, it's just a different direction. If you put your roll center at the center of gravity the car doesn't roll while cornering, but people don't do that. Having your roll centers on the ground and also zero anti is sort of the simplest and purest setup. In many areas more is not better.
"And the dim bulb began to glow"... Thank you Marcus, now I have a better understanding of how the C4 suspension actually works. I had read that they went to the 4 link to get a longer virtual swing arm over what they had with the C3, for exactly the reason you stated of fore and aft movement of the hubs. Much clearer now. So if I understand this correctly, without also being able to change the heights and locations of the HUB mounting points and the lengths of the dog bones, changing the angles of the dog bones won't really give me much adjustability at all without screwing up the virtual swing arm length and other factors. It would appear that the best you could accomplish is making the virtual swing arm longer, at the expense of increasing the anti-squat %.
So, since the attaching points at the hub are not conducive to being modified,and there is now way to make the dog bones longer, it would appear I'm best off leaving the setup as it came from the factory, and living with my choice of suspension, good or bad.