Fabricated A-Body spindle ideas and discussion
Here is what I found from when I did the calculations previously. Though I'm not saying mine were accurate either.
I think anywhere from -1 to 10 inches is workable, 2-5 is probably better. Interestingly the stock Duster (according to the calculations I did before) has better RC height of 4.02" vs the F-body spindle at 7.75" and I'd guess the raised UBJ moves it up even further.
@DionR May be able to calculate the RC with his measurements as it is pretty easy with the setup he shows:
Here is my comment from the video so people don't have to search for it and since it is applicable for this discussion. I still agree with myself. Haha.
"It is really cool that you are developing stuff like this for classic mopars. A lot of my experience comes from the A-body world (they have better geometry from the factory), but I think the direction you're going in with this modification is probably not the best. It is pretty common knowledge in the racing world that a lower roll center is better and more predictable than a high roll center. This does create more body roll but that can be counteracted with different devices like sway/anti-roll bars. In the book "advance race car suspension development" by Steve Smith he even says "a racing vehicles roll center height should be as low as practical so that the lateral acceleration is transferred into body roll rather than lateral displacement at the outside tires contact patch with the road". The problem with raising the roll center is you increase the loads along the suspension arms and can even create jacking with a high enough roll of center. Increasing spring rates through bigger torsion bars and roll rates through better anti roll bars would probably be a better solution then trying to raise the roll center. Not to mention the liability issue if one of these breaks and causes an accident. Not trying to be a downer, just looking out for the community as a whole. Also those brakes are sweet. I'm working on a similar setup for my duster."
Agreed. I saw a later video of the car running and it has almost no suspension control. Just flops side to side.
If I'm reading this right you have zero anti-dive with the UCA pivots at the same height? This is pretty unusual and would be pretty hard to do with an A-body. Or did you average it? What kind of accuracy do you think you had with your measurements? How did you identify the centerline?
Here is what I found from when I did the calculations previously. Though I'm not saying mine were accurate either.
I think anywhere from -1 to 10 inches is workable, 2-5 is probably better. Interestingly the stock Duster (according to the calculations I did before) has better RC height of 4.02" vs the F-body spindle at 7.75" and I'd guess the raised UBJ moves it up even further.
@DionR May be able to calculate the RC with his measurements as it is pretty easy with the setup he shows:
Here is my comment from the video so people don't have to search for it and since it is applicable for this discussion. I still agree with myself. Haha.
"It is really cool that you are developing stuff like this for classic mopars. A lot of my experience comes from the A-body world (they have better geometry from the factory), but I think the direction you're going in with this modification is probably not the best. It is pretty common knowledge in the racing world that a lower roll center is better and more predictable than a high roll center. This does create more body roll but that can be counteracted with different devices like sway/anti-roll bars. In the book "advance race car suspension development" by Steve Smith he even says "a racing vehicles roll center height should be as low as practical so that the lateral acceleration is transferred into body roll rather than lateral displacement at the outside tires contact patch with the road". The problem with raising the roll center is you increase the loads along the suspension arms and can even create jacking with a high enough roll of center. Increasing spring rates through bigger torsion bars and roll rates through better anti roll bars would probably be a better solution then trying to raise the roll center. Not to mention the liability issue if one of these breaks and causes an accident. Not trying to be a downer, just looking out for the community as a whole. Also those brakes are sweet. I'm working on a similar setup for my duster."
Agreed. I saw a later video of the car running and it has almost no suspension control. Just flops side to side.