does size matter?
 

ahh .. i mean ... for the fuel lines?

my factory plastic return line is smaller than the feed line. i think it's the same on FI cars too.

why is the return line smaller?

i'm replacing the plastic lines and using a bosch -6 fuel pump.

it's my understanding that the factory pump doesn't need a pressure regulator. is that due in part to the smaller return line?

TIA,

doug waters