what is the roll center of a car and how does it affect handling?

[00 scrub]

Well I was reading about the Whitline suspension kits for fun when I came across their adjusatble roll center kit. I am assuming the roll center of a car a point along the axis of roll of the car. But what point? How does changing the roll center affect the transitional and steady state handling of a car? more specifically the Celica. Another question I have is the effect of more caster. Whiteline also sells another suspension component for the Celica that I have not seen on any other kit thier "anti-lift kit" which adds 5 degrees more caster to the front wheels. How does this change the characterisitics of the car?
Thanks

[00 scrub]

bump. I know there are engineers somewhere onthis board that are willing to answer this for me :).

[digitalSamurai]

when you change the ride height of the car you change the overall suspension geometry and alignment of the car. The roll center adjustment kit is supposed to make sure the car's roll center is closer to normal specs, but while allowing you to take advantage of your stiffer suspension.

I will post my results this year when I have time to install my roll center adjustment kit (I got it when I ordered my whiteline swaybars from www.pdm-racing.com)h

[00 scrub]

Thank you. Could you explain how this works, and why having the roll center at a certain point would be beneficial?

[marcus_GTS]

Check out this link, and search the page for "roll center"

http://web.umr.edu/~formula/library/sae_paper/paper.html

[00 scrub]

Thank You. That article is very nice. I nede to read up a bit more on smoe of the terms but it makes sense. I have one question fromt he article. It states that having the roll center above ground would give the outside tires + camber, but what about a roll center below ground?

[scapamouche]

The problem with roll center below the ground it it means the center of gravity of the car and roll center are far apart, leading to edgier handling and more body roll.

Grassroots Motorsports did an article on the suspension of their Project Mustang LX a couple issues ago that discussed the whole roll center thing. It was very informative. If you can find back issues (ormaybe it's posted on their website) I think most of your questions would be answered.