What's the least PSI i should run on the track?

I have a set of tires that have little thread left on a spare set of rims that i own. I wanted to use those for the track i've driven those until last month when i bought a new set of salad shooters with tires. What would the least recommended PSI be for the track for best traction but to not blowout the tires on the run (if that's possible). They are 245/50/16s and are Z rated

By if that's possible i mean is it possible to blow out the tire if the pressure is to low at high speeds or to loose control. With regular pressure i've hit 130mph on the highway with these tires many times no problem.