Fitting a fuel pressure regulator with gauge to my 1993 wrx and would like to know what the fuel pressure reading is in psi or bar for 380cc injectors?

 

Well, std should be showing about 2.7bar/39psi with its vac line connected, or 3bar/44psi with it disconnected.

 

Thanks alot mate,that helps.

 

And what will be the reading if i got an ej20g to but i upgrated injectors to a 550cc.

 

The same.

 

You can only up the pressure if you replace your existing OEM FPR with an aftermarket adjustable one, and map for it. This allows whatever injectors you fit to flow a bit more than whatever their 'normal' 3-bar pressure cc/min rating is (depending on how much pressure you set the FPR at)....

 

Remember to set it once the engine is fully up to temp and on warm idle