Suspension Modeling

I was wondering if anybody can help me model my suspension, or at least give me some insight into how this will work.

Here's the information I have right now.

Four Wheel Struts

Motion ratio front 1.2

Motion ratio rear 1.15

Bars are mounted to the struts, or they would be if I had any.

Spring rates are 488lb/inch on all four corners.

Virtual Arm Specs:

Front A-arm is 5.5 inches off the ground at the knuckle.

It is 6 inches off the ground at the pickup point at the subframe.

The a-arm is 13.5 inches from the knuckle to the pickup.

The A-arm pickup is 16.25 inches from the center of the vehicle.

This results in a roll center height of 6.6 inches and an inclined slope of .037(x) in y=ax+z Cartesian coordinates.

The rear control arms (there are two for each wheel, they are parallel) are 8.5 inches high at the knuckle and 9.75 inches at the chassis pickup point.

The control arms are 21.5 inches long and mount 5.5 inches from the vehicle center line.

This results in a slope of .055 and a roll center height of 10.02 inches.

Track width front is 68 inches.

Track width rear is 66.5 inches.

Wheelbase is 100.75 inches.

The roof height is 54 inches as measured at the b-pillar.

My observed roll rate is 2.5 degrees at maximum cornering G.

I'd really like a reasonable method for calculating COG from this, or at least a good way to estimate.

I'd also like to get some idea where the suspension will start jacking during cornering.

Am I wrong in assuming this suspension should have a pretty good camber curve for a strut, especially in the front?

Am I wrong in assuming this car has unusually high roll centers? Is there a downside to this or does it just give me a free pass to run with no bars and relatively soft springs without much body roll?

For comparision, I calculated my roll rate at 2.5 degrees. This car is about 2.3.

How much does your vehicle weigh? The downside of a high roll center is going to be a large jacking force. Your jacking force is going to be equal to the lateral force times the tan of the line connecting the contact patch and the roll center. If the front roll center is too much lower then the rear, the car will not enter corners well and will exit on three wheels. I would prefer a lower roll center and adjust the roll with swaybars and springs. If get a chance I can model the suspension with Racing by the Numbers. Shoot me an email with the specs if you don't mind.

Thanks a lot! Email sent.

I don't think the roll center axis is excessive. I normally lift a tire on corner entry and put it down as soon as I get on the gas.