Quote:
Originally Posted by BR3W CITY
Over 18" away and you start to GREATLY increase the wear on the pump. The 255lph walboroughs survive "pull" better than most others, and even so, they do not recommend going too far from the pickup point. There IS a reason that in-tank pumps are the most common from the manufacturers, and its not cost. The pump needs fuel to cool, and drawing it farther means more heat and strain on the pump. Only time you can get away with a large distance from the pickup, is if the tank is higher than the fuel pump, and you gain the gravity advantage to keep fuel against the pickup point.
Fuel pressure on the lines of a cummins truck is only about 14psi, so its not really the same thing. Low psi pumps can run a huge amount of suction. The cummins doesn't get high fuel pressure until AT the injectors.
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Im running a walbouro 255 inline and its about 5 1/2' from the tank. Running diesel no less. Little thicker than gas.Sure auto manufacturers place them in tank for cooling and durability purposes. And I have mine set at 30# of pressure running into my high pressure pump. So its bypassing a lot of fuel from the regulator back to the tank. Is it a ideal set up, prob not. But works and has been for a long time. And its a pretty common set up in the dodge diesel world. The only problems I could see in using it in "our" application is the amount of return pressure reverted back to the tank. Im just guessing and saying around 10psi? It is free flowing. May be more may be less, but without finding a way to measure it no one really knows. I think it would be safe if it was as much 20# back pressure on the return side. But everyone should be cautious none the less on the return side.