Double pumper plubing ?? Twin 255's

[20psiofevil]

I know some of you guys use the red's piece with the 2nd pump wired on a boost switch. My question is, is there a one way valve after that pump so the main pump just don't pump through the 2nd while at cruise and idle.

I'm upgrading my fuel lines to -8 feed and return (ordered $320 worth of fuel lines and fittings last night) so wonder if I should just run both pumps all the time and skip the boost activation switch.

 

[pacecarta]

intank pumps have a check valve in the outlet port, you can verify the check works by the fact that the fuel pressure holds after the pump stops
you could run both pumps all the time depending on your regulator , external may work , on the rail style regulator probably will cause the base FP to be higher than desired
and running both all the time on the street youll just be wearing them out quicker , at the track if your regulator will allow you could keep both on
-08 return is pretty much a waste on a -08 feed in an efi setup when the min pressure will be around 38psi
-06 would have been plenty .
on a carb setup where base fp needs to only be between 7-10 psi the lines should be closer so

 

[20psiofevil]

I would have done -6 but I bought a -8 kit and will have fittings and line left over to plumb the return. I deleted the check valve (pprv) on my setup because it was too restrictive. I do have a diaphragm style check valve I was going to use.