After 2 years of JWT TT and built motor I've never really gotten away from the "Bubble" issue of the cooling system. I've been purging once or twice a month to stay ahead of it but it's still a PITA. I upgraded the radiator prior to going TT but have been running a factory 13psi radiator cap ever since.

I found that the rad caps I've been installing only lasted a few months before they would stop holding 13 psi so while I was at the parts store a few weeks ago I saw a 16psi cap that looked just like mine and fit perfect. So far it has worked great and I'm hoping this will be the ticket.
My question is what psi cap are others TT owners using other than those using Evans NPG. I test my cooling system monthly at 20 psi so I don't see a problem.