LS1 - Fuel System Design and Construction
Hi Everyone,
The fuel system is the first area that I had to address because it is very different from the one employed for the Lycoming. The LS1 requires that pressurized fuel be supplied to the injectors via a fuel rail. This is a looped system with more supply capacity than will be used by the engine. The unused fuel is depressurized at the termination of the fuel rail by a fuel regulator. It then returns to the supply tank. This differs from the lycoming set-up in that there are no return lines required.
So to begin with we are adding complexity to the fuel supply system. There are quite a few more lines involved in the LS1 set-up that have to be bent and flared to get the fuel to the engine and back.
Header Tank
On a component basis I am going to start with the header tank. I installed a quart sized header tank on the cabin side of the firewall on the pilot’s side. This tank serves a couple of functions that are very important.
The first function is to keep the high pressure pumps always wetted. Automotive style high pressure fuel pumps do NOT like to be run dry. This would be a very real possibility should you mount them in the wing tanks.
The second function is to act as a collector and distributor of two streams of low pressure fuel. the low pressure pumps feed fuel to this tank and the pressure regulator returns depressurized fuel back to this tank. This keeps the fuel cool. Allows for any bubbles in the fuel to move away from the high pressure pump intake ports and provides a path for the fuel to be returned to the supply tank.
The photo above shows a large portion of my fuel system including the header tank, supply lines, return lines, twin high pressure supply pumps, and fuel transducer.
Next post I will describe the high pressure pumps and how I have installed them.
Dave