After talking with a friend who runs caltrac's on both his 8 sec., wheel hanging footbrake cars I found out some valuable infromation.
The preload settings caltracs recommends are really designed for TRANSBRAKE cars!! With a transbrake there is no load on the suspension until the button is released. Totally different when footbraking.
His first reccomendation was to check the spring travel. there must be at least 4.5" of travel in the suspension. Measure the tire to the wheel well when wieght is on the springs. Then jack it up and support the frame letting the rear wheels hang. Measure the distance again. If you don't have at least 4.5", the caltracs will not work properly.
Next, you want to set the preload WHEN UNDER FOOTBRAKE LOAD. In other words, you want a half turn or so of preload when the suspension is under staging load!!
If you watch any of the videos of my truck at TS you will see how it was hopping and spinning all over the place. I had it set with a half turn of preload in the static position. After talking with my buddy, I took his suggestion and set them up as follows:
On level ground, I adjusted the bars finger tight until the pin just touched the springs. Then BACKED them off 3 full turns. This places the pin 3/8-1/2" from the spring.
Since TS, my truck leaves hard and solid. No hopping, no spinning.
