Re:Fuel Rail... how much PSI?
 

i thought the stock fpr only worked as a on/off function.


off-- less gas at idle(when the fpr sees vacuum), on--- more gas while driving (when the fpr doesnt see vacuum)

im not sure, correct if wrong.

Re:Fuel Rail... how much PSI?
 

If I remember correctly STOCK b16 fuel rail pressure is about 42 psi or so. I'm assuming the other B series are right around that as well.

And yes the 450cc maxes around 12psi of boost, but I guess it also depends on what turbo you are using. If you have it tuned and it works at 18-20psi then its cool, otherwise you might wanna go up to 550cc's injectors or even higher.