Are you guys preloading the caltracs (if so how many turns?).. Or leaving an "air gap" .. or just barely touch the top part of the leaf spring?

 

When on the street I leave at "zero lash" as I call it. The bolt just touching the leaf. But at the track you obviously want to pre-load it. I can't say what you should try, because every vehicle is different it seems. Just play with it.