Hello all,

I have an Aeromotive street/strip electric fuel pump on my 502. The pump is mounted near my fuel cell with #8 line to a BG regulator. From the regulator I have #8 line to the carb. Pressure is fine car runs great. When I touch the fuel pump (After driving the car a short distance 4miles) the pump gets red hot! I’m guessing I need a bypass regulator. My question…when researching the Barry grant site on bypass regulator plumping, they show a direct line from the electric fuel pump to the carb with the bypass regulator mounted behind the carb. I’m not understanding this concept. Would I still need a regulator before the carb to regulate the pressure coming in? I’m not sure if I should remove my reg before the carb. Why does Barry Grant only require a bypass regulator after the carb and not a regulator before for carb with this type of system? I know this may seem like a dumb question, but I’m having a hard time seeing this one. Any thoughts? Thanks!! Joe

The pressure in front of the regulator between the pump and the regulator is held at the adjusted pressure you set. So a carburetor in the supply line sees the fuel delivered at that pressure, and with as much volume as the supply line can provide. Any excess pressure, and unused fuel is allowed to return to the tank. This keeps the pump pumping at full capacity and allows the gasoline going through the pump to cool it.

When you dead head a positive displacement pump (like the Holley, BG, and Aeroquip pumps) what gas that isn't used by the carb has to recirculate within the pump its self via a small pressure relief channel in the pump. This concentrates the heat in the pump, and often results in vapor lock in city traffic.


Larger Dave

A full bypass system is the best way to go. It just makes sense. Unused fuel goes back to the tank. Pressure is maintained to the fuel bowls. All the time.
Another benefit is that the pressure bypass is in the return line, not in the fuel supply to the carb. In other words, no restrictionin line with the carb.

I have tried to convince my buddy with the 502 Chevelle to run this type of system. He still runs the Holley black pump with the total POS Holley blue dead head regulator. Shoot, the restriction in the regulator is greater than his needle and seats. I have even offered to give him a free Mallory return style reg....but he is cheap and doesn't want to buy fuel line for the return path. Whatever......he keeps complaining that his car won't pull on the back half. My car gets down and hauls ass to the finish line.
Of course this keeps him .5 seconds behind me in perf.....

Mount the reg/bypass near the carb, and run a return line from there to the tank. Maybe it won't add perf....that depends....but it is the correct way to plumb a fuel system IMHO.

Ron

Thanks everyone!

I have already had one pump burn out do to excessive heat. I hate to loose a second pump. I’m going to run a bypass regulator and return line as illustrated in the Barry Grant 220 plumping instructions..... (http://www.barrygrant.com/bgfuel/default.aspx?page=85).

Joe:)