well in not sure about si but i own a ex engine d16y8 vtec umm i put 7 psi on it sock and the engine blew up. i had to install new pistons, valves,crankshaft ect..now i have 20psi on it and the engine never blew up
depends how long you want your nmotor to last. you can put as much boost into a motor you want, but the more boost the more likely it is to fail. If it isn't a turbo motor already I wouldnt reccomend putting a turbo on it due to the way the engine is built. IT wont get enough oil flow to keep everything cool. If it already is a turbo motor you can give it a fair boost and it will more then likely take it. depends if your using it as a daily driver or strictly a track car. -