clausen
04-03-2006, 12:54 AM
Hi,
I've got another curly question that relates to a pretty different racecar to an FSAE. There are a lot of clever vehicle dynamics thinkers on here that I thought might be interested in coming up with some theories.
I currently work on racing a large sedan with a 650hp engine, wishbone front suspension, live axle rear with watts link, and a spool diff.
Some apparently typical behaviour with these is that when they have understeer issues, more rear spring can make it worse, and more front spring make it better.
Can anyone think of why? I was thinking that increasing front spring mihgt just be reducing bodyroll therefore reducing camber change at the front, but I don't think this is the case, especially as more rear spring doesnt help.
I thought that maybe the damping ratio was so bad that increasing the rate brought the damping ratio to a better place, which might increase grip. But I know that the dampers aren't that far out.
Something else I've read is that drivers can complain of understeer when the car is too tailly and after correcting a bit of oversteer on the way into the corner, the car starts understeering becasue they're turning in for the second time.
Has anyone got any other ideas? Anything that might relate to tyre sensitivily not working as per normal in certain situations?
I've got another curly question that relates to a pretty different racecar to an FSAE. There are a lot of clever vehicle dynamics thinkers on here that I thought might be interested in coming up with some theories.
I currently work on racing a large sedan with a 650hp engine, wishbone front suspension, live axle rear with watts link, and a spool diff.
Some apparently typical behaviour with these is that when they have understeer issues, more rear spring can make it worse, and more front spring make it better.
Can anyone think of why? I was thinking that increasing front spring mihgt just be reducing bodyroll therefore reducing camber change at the front, but I don't think this is the case, especially as more rear spring doesnt help.
I thought that maybe the damping ratio was so bad that increasing the rate brought the damping ratio to a better place, which might increase grip. But I know that the dampers aren't that far out.
Something else I've read is that drivers can complain of understeer when the car is too tailly and after correcting a bit of oversteer on the way into the corner, the car starts understeering becasue they're turning in for the second time.
Has anyone got any other ideas? Anything that might relate to tyre sensitivily not working as per normal in certain situations?