I have an early cat, #2036. If the diameter of the welded banjo fitting at the top of my fuel tank is 5/16, I assume that that is also the diameter of the fuel pickup inside the tank. Would running a 3/8 line from the banjo fitting to the pump to the carb increase the flow, or is it limited by the 5/16 tank supply?
Does anyone know the diameter the supply tube of Wilkinson's upgrade to the combo fuel sender/ fuel supply?
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Wilkinson explained to me that the stock fuel pickup is restrictive to high hp engines, perhaps 450 or 500. Hence the addition of the large diameter pickup tube to his fuel level sending unit Another option is to convert the tank drain plug to the fuel source. On my latest project Pantera the EFI source is the drain and the return is the stock pickup. Its electric fuel pump requires a source at the bottom of the tank.
Also, I think it’s a 3/8 diameter pick up in Wilkinson’s sending unit. But this should be verified
Thank you Steve. I've ordered the Wilkinson combo replacement so I can hopefully have a 3/8 feed from start to finish. My 2036 doesn't have a bottom tank drain to tap into.
Steve is correct but that's really only an issue at Bonneville or maybe the Silver State Open road races where you're at full throttle for many minutes at a time (in any gear). Then the engine may go lean and burn valves.
As I remember, the late fuel gauge sender with external fuel feed is a bolt-on but uses the same (metric size) 5/16" OD fuel line. In the past I welded up a few of these substituting 3/8" OD U.S. steel tubing. You need the old sender parts to do this so don't s-can an inop' one.
When adding the late sender in early cars, the rust-prone welded tank line can be used as a fuel return for EFI systems even if perforated. Or just cap it.
Thank you Bosswrench. So can it be said that hooking up a 3/8 fuel line from the top of the tank containing the original 5/16 tube all the way to the carb would do nothing to increase the flow?
My opinion is, for a carbureted engine which runs at 5-7 psi (or TBI which runs at 10-15 psi), AND you have a seriously pumped up engine AND run it at or near redline for long periods, you need 3/8" lines all the way from the fuel tank to carb. With port or 8-stack EFI which runs at 45-55 psi, the stock 5/16" lines will flow enough for any street engine.
Incidentally, a Ford TBI in-tank electric fuel pump will fit thru the stock sender fitting in our tanks and can be regulated down to carb level. It is also quiet. Just be careful- TBI pumps look identical to high pressure EFI pumps which CANNOT be regulated down to 5-7 psi without overheating. And once out of the box, neither are labelled as to the pressure delivered. I use my regulated TBI pump for priming the carb after the cars's been setting awhile.
