The caster is killing you. Same thing happened to me, was fighting tight tight tight could never get the car to rotate. Reset my caster to 0 degrees and was junk loose without changing anything else. Found a happy medium at about 4-5*.

With a ton of caster it makes turning the wheel a physical chore. Sprints and midgets run that because they have power steering and it helps transfer weight with steering input. The lightning sprints can't do it unless the driver is the Hulk.