For daily driving, I keep the electric pump off, the mechanical pump is pumping 87 at 3-4psi through it's one way valve to the carb. It can't go back into the electric side of the system because the electric side has a one way valve too. So this way I can run 87 for normal driving.
For fun driving, I flip the electric pump on right before I want to step on it, it pressurizes the fuel system with 93 (or race fuel) because I can set the regulator higher than pressure the mech. pump puts out. So if I set the regulator to 6psi and the mech. pump only produces 3psi, the electric pump will force the mech. pump's 87 back up to the one way valve on the mech. pump side and keep any of the 87 from getting into the line since the mech. pump can't create enough pressure to overcome the electric pump's base pressure. SOOO... that way the electric pump will fill the fuel circuit with 93 when it's on and it will create too much pressure to let the 87 flow past its one-way-valve. That will allow me to choose when I want to run the more expensive fuel but will also allow me to get REALLY expensive fuel (i.e.) race gas because I won't actually be burning it all the time.
MBHD: That's the whole point, I won't *really* be running 87. Just for light acceleration and cruising. When I want to get on it, I basically switch the electric pump on which will overpower the 87 with 93 because of the pressure difference of the mech pump (3psi) and the regulator base pressure (5-7psi) and then I can run off of the 93 for as long as I want.
Look at my diagram. I'm going to run 6AN fuel lines through everything which is the equivalent of 3/8" line. I've read that should be good up to like 375hp which is where I'll probably top out this engine. But I'm more doing this because that's the size of the inlet and outlet size on the pump and regulator. Also once I get up to the 1/2"/8AN pumps, they start at like $300 for the cheap ones.
Do ya'll have any comments on using that pump and regulator? I did my research and I'm 90% confident they'll do what I need them to do but I'd still like your "blessing" if at all possible haha.
EDIT: So is the line from the mech. pump to the carb 5/16"? So what size fitting would I need to find to adapt it to AN? Would it be a 5/16 to AN or would it be slightly larger like 3/8 to AN? because I'm trying to find an adapter for the outlet of the mech. pump to AN but they don't make ANYTHING for 5/16" to 6AN. It's either 1/4" or 3/8" to 6AN.
Last edited by snowman4839; 11/30/1108:40 AM.
69 Buick Special Deluxe. Intercooled Turbo Chevy 250 @ 15psi on a stock long block. It's kinda fast.