i have a R33 series 1 skyline rb25
i got a stock turbo and have a 3in exhaust. i just bought a manual boost controller and im wondering how many PSI / 100mmHg i can run without any other mods.

from what I have heard you don't want to boost more than 12PSI on the stock turbo

I have an R32 GTS-T and I've driven it daily at 1 bar since I've owned it and have had no trouble. I cranked it up one time and it showed 1.4 bar but I backed it off immediately, the last thing I need is a grenade under the hood. I know a few guys with GTS-T's and all of us agree that 1 bar is sort of the safe limit, however turning it down is never a bad idea.

I've seen lots of guys running 1 bar with the R32 GTS-t, even higher. Most are very lean until they do a fuel upgrade and an adjustable fuel pressure regulator.

Also the R33's have a factory boost cut around 1 bar.