I need to plumb my two fuel rails on my 20b.  originally it must have had rubber hose connecting them.  should I run rigid lines? AL or steel?  I guess I'll have a braided line from the firewall to the first rail, with the pump behind the firewall somewhere, and another braided line for the return.  somewhere I need to insert a fuel pressure regulator, since I sawed off the one I had thinking it was something else (duh).  will it need to be in the engine compartment?

Kevin Lane  Portland, OR

I chose to use the same Briaded SS Teflon I used for the rest of the run; but I see no reason not to use solid steel for a run between fuel rails where there is no relative movement between the connections; but of course support it so it doesn’t vibrate.  I suppose Aluminum with firesleeve is OK, but Aluminum does melt and burn at high temps.  When using braided SS I’d definitely recommend using AN fittings and tube ends anywhere on the engine side of the firewall.  I used aluminum at the pumps and filter, but have them at the bottom of the firewall, the last place to get hot in the event of a fire.  Perhaps I should also firesleeve them there.

The thing you cut off was likely just the pulse damper that Mazda puts on the primary rail.  Best to get rid of that anyway, because they are subject to leaking.  Pressure regulator goes downsteam from the second fuel rail.  TWM makes good units; and get one that has manifold pressure reference if you are using Tracy’s ECU; even for a NA engine.  My system is: sump tank (with sample drain); dual fuel pumps; high pressure filter; pressure sender; primary rail; secondary rail; pressure regulator; return to sump (4 gal).  Doesn’t matter which rail comes first (or you could pumb them in parallel), and if you don’t have a pretty good sized sump or header tank, you may want to return to a main tank.

FWIW,

Al