I'm in charge of the suspension geometry for my team's car this year. I already have the front design pretty solid, I based it off last year's and used WinGeo3 to confirm the last team's calculations and to make a few adjustments of my own.
For the rear though, we have a big empty area in the frame behind the diff that serves no purpose but to mount the suspension to. So the big thing I'm looking to change is to bring the rearmost chassis points forward as much as I can. We want to have the diff hanging halfway out the back.
The current design is a double wishbone SLA pullrod type with the A-arms being isosceles triangles with the hub centered. And the toe links are mounted parallel behind the lower A-arms about a half an inch.
So I was basically looking to have the A-arms become right triangles by moving the rear chassis mounts to be in line with the wheel center. This is ok and dealing with the changing of the A-arm loads shouldn't be problem. But I don't like having the toe links behind that making the lower chassis a half inch longer and they seem pointless to me in the end.
What I am interested in doing is one of two things. I've seen designs with the toe links attached to the lower A-arm and I think that may be a good way to eliminate at lease half of them. Just have them triangulate to the midpoint of the lower arm and weld them to it. This seems like a pretty reasonable design and I'm keeping it in mind.
My other idea is to get rid of the toe link all together and have the A-arm become an H-arm. Instead of having the two links of the lower arm come to a single ball joint, one would go to the current position and the other would go the where the toe link mounted. More or less that is, the exact position may change. I may also need to weld the two links together with a cross brace but I'm not sure if that is needed.
I was wondering if anyone had tried an H-arm type rear suspension or has their toe link attached to their arm and if they have any advice. I can't even model this with WinGeo3 as it doesn't seem to recognize that as being a valid design. And I'm having a lot of trouble finding any information on this in detail pretty much anywhere. Both these ideas were mentioned in passing in "Race Car Vehicle Dynamics" but no details were given.
Any ideas on how to design a rear suspension with the chassis points far forward of the wheels and diff would also be a big help. I know I've seen teams with this sort of setup.
Thanks in advance.