Originally Posted by splinter
Yep. I understand about adding a return line. Unless one does away with the OE filter on the supply side, the fuel rail will still only reach its regulated maximum pressure.
Perhaps there’s more to this modification than has yet been shared…
Fuel pressure can be regulated after or before the rail. Look at it this way.... Fuel, like air, is lazy. It will travel the path of least resistance. Most vehicle adjust post rail if a return system, where as returnless system use fuel pump modulation on a diaphragm type filter to change pressure. Im just 100% sure what out system is from the factory. Obviously if its a return system its easier to modify.