Coilspring datapoints for lightweight car wanted

[JohnJL]

Hi,

I have a few other threads on this car on particular topics. I am placing my suspension order and would greatly appreciate some others' experience with cars in similar setups. This car is for autocross/weekend hoots.

The target weight is still about 875 kgs/1975lbs, assuming a 40/60 split thats 180kgs/400lbs on each front corner. 270kgs/594lbs for each rear corner.

I've fully seam-welded and gusseted the car. My intention was always to go coilsprings in back for ease of adjustment.

I had until recently intended to keep with torsion bars in front as that adjustment is easy and the weight is down low. However in discussion with the shock builder, going to coilsprings in front is less than the cost of a set of hollow torsion bars and comes with some advantages too so I am going to go coilovers in front too.

Some of you had previously suggested around 19mm front torsion bars and 28mm rear. I could use some help confirming that approximation but more to the point, what springrate in coilsprings is about right. From some of these threads I understand its not just a straight arithmatic conversion since the pivot points/leverage points are different between these two springing methods;

Torsion Bar Calcs

The shocks will be dual-adjustable. I have tarret adjustable sway bars front and rear.

Some examples of where you settled or experimented with lightweight cars and springrates would be greatly appreciated!

Thanks

[TRE Cup]

On a light car , such as yours, and the intended use we have had good results with 350 lb rate on the rear and 200-250 front

[Flieger]

Dave's recommendations are the same as my wheel rates according to my calculations.

I run 22/31 torsion bars and I feel it's a little too soft for my ride height. If I hit a bump mid-turn it can (not always) bottom the front A-arm on the chassis. I took off my sway bars though since the ride and handling seemed better halfway through my sway bar swap. Sway bars might help the bottoming a bit.

Otherwise I really like the ride and handling. My use currently is only for fun on twisty roads- no track or autocross at the moment.

My car is about 2200 pounds with me in it and with a half tank of fuel.

[JohnJL]

Thanks very much guys.

John