Newly installed turbo overheating help.

So after a lot of long hours, I finished turbo charging my car. I am on Crome free until I order eCtune. I couldn’t get it to idle on the RC 650cc injectors so I put the stock ones back in until I can get it tuned. I have a 5psi spring in the wastegate and try to stay out of boost. I used boost tools to retard ignition 1 degree per pound of boost and I multiplied the entire table by 120%. It runs okay with a few hiccups here and there and air fuel cruising in vacuum is right around 12.8 to 14.3. I have a civic size PWR race radiator and haven’t changed anything in my cooling system while installing this turbo set up. I have been running this radiator forever with no problems. Now I just on the highway for about 3 minutes and it started to overheat rapidly. I was wondering is the mass amount of ignition retard could do this perhaps? Thank you.