Radiator hose blows off under boost? Why?

[r1jlewis]

I'm using an AEM EMS which I just had it tuned a couple of days before we took it to the track, and we tuned it for the max boost I was running which was 25psi and it all looked good tuning wise. I just put a set of ARP head studs in this time and torqued them to 65flbs, which was what they suggested. One big variable since then, the plugs I had at the time were older and so I put a new set in before we took it to the track. I was originally using NGK's bcpr7es but was sold champion's rc9yc4 as a comperable set. Would that cause the problem?