For suspension, I'm no salt pro but I'd just make sure you don't scrape the surface, and have preload and damping that works best for high speeds. You sound like you know what you're doing. For ballast, below is some info that was posted by Rex Svoboda years ago. cheers, Dean
It is a balance of forces. You have aero drag and rolling resistance that are pointing one way, and forward thrust of the wheels against the salt pointing the other when the two are equal you won't go any faster. Aero drag is pretty much a constant related to the frontal area of your car and it's coefficient of drag and the velocity that you are going and can be calculated in pounds by using this equation: Cd x 1/2(density of air in lb/cu. ft)(velocity, in feet/sec)squared x (frontal area in square feet)= pounds drag. To get velocity in ft/sec from miles/hour divide the mph by .681 and the density of air (as sea level) is .00238 lbs/cu.ft.
So lets say your roadster has a frontal area of 12 square feet and a Cd of .75 and you want to go 200 mph. The drag force would be:
.75(.5)(.00238)(200/.681)sq x(12)=923.75 pounds force. From this number you can look at the coefficient of friction for the tire/salt and come up with an estimate of how much weight you need on the drive wheels. If the coefficient of friction was .5 you would need to have about 1850 lbs on the drive wheel. I have not included rolling resistance which is related to tires, salt conditions and car weight and can be a much more difficult thing to calculate because of the various data required that is difficult to obtain accurately.
All of this assumes that the tire is on the ground 100% of the time which as John (JL222) says it dependent on wheel rate and suspension. Nothing is easy or exact but these calculations can get you to a starting point.
Rex
