A picture heavy post about fuel systems

There are a few post going on about aftermarket fuel systems.

So far I have feed the engine to 10 flat @ 131mph with a little comp 140. Pressure is rock steady.

I did a ton of research and take pride in my workmanship.

As Foose says,"It is all in the details". 😀

Here is my set-up.

From the cell are 2 #8 lines along with 2 metal mesh filters to protect the pump with minimal restriction. The fitting after the Y is bored out to #10.


Here is a side view



The fiitings are full flow 180, very hard to find



The fuel line exits the trunk shelf, later a rubber grommet was added



The cell is mounted as high as possible and still letting the trunk close. I take the fuel line off the carb and drop it down about 2" and fuel will gravity feed thru the pump/reg/filters!



The fuel is wired threw a relay direct to the battery. Also has a direct ground to the thru fitting,lower right.



There is a very large paper fuel filter before the regulator,this way any restriction is before the reg. It is mounted on the plastic fender liner to keep vibration and heat away.The lines to the carb are also #8



The system was laid out to have very few bends/turns. The only 90 fitting is on the high pressure side before the regulator and is full flow style.

Here is the same basic system with my dual quad system I am planning. Considering a Comp 250 pump just because the Q-jet don't have the "fuel storage" capacity as the dominator.

The small lin is a pressure feed to the fuel pressure isolator on the firewall. It allows me to run a pressure gauge in the car. For some reason NHRA does not want pressurized fuel in the driver compartment. 😀

The return is the red line in the bottom diagram. It goes into the upper left fitting on the cell. If the cell did not already have the fitting, I would have mounted just above the fuel pump in the cell.



I copied this from MR, don't agree with it 100% but some good basics:

"I wrote a reply to a similar question on another forum this evening so I'm pasting it below.

A "dead Head" system has no return line to the tank. Many people feel that a return line (from the pressure regulator) increases the life of the electric fuel pumps by allowing them to run cooler.

The way most aftermarket electric fuel pump systems are installed on non fuel injected cars works like this.

1. Fuel line from fuel pickup in tank to a canister type fuel filter close to the tank. Filter prevents dirt and rust from becomming an abrasive to the vanes in the pump. (keep in mind there may also be a "sock" or other stock filter in the tank on the pickup)

2. Fuel line from filter to electric fuel pump with pump located in rear of car also close to tank. It's said that electric pumps work better pushing fuel than sucking fuel. It's also said that the pumps have an easier time providing consistant pressure to the regulator under the high G forces of a drag race type launch when pushing from the rear.

3. Metal gas line tubing has to be routed on the exterior side of the framerail as it passes past the coupling of the engine and transmission to be legal for most racing sanctioning bodies. This way if a flexplate/convertor/flywheel/ clutch lets go it won't cut through the fuel line.

4. A regulator is used close to the carb to adjust the fuel pressure so the pump won't overfill the carb. 7-9 lbs pressure is recommended by most carb manufacturers.

5 A fuel pressure gauge is used between the pressure regulator and carb to provide info necessary to adjust the regulator properly. It is usually left in place after adjusting to monitor fuel pressure occasionally and, well, just because it looks cool.

Tips (I'm sure I'll forget some so others chime in if I miss any)

NEVER allow an electric fuel pump to run dry. Doing so wears the pump out very quickly. Although the car may run after operating the pump dry the pump will probably fail in the near future.

Do not run the gas line up the firewall and mount the regulator to the firewall. It's a neat looking, easy place to mount the tubing and regulator, but is dangerous and will not pass tech inspection due to the risk of a clutch or convertor setup blowing and causing fire.

Keep the fuel lines away from anything hot. Hot gas makes less power and vapor lock problems can occur. Oh ya rubber hose sections can melt and then FIRE!

An oil pressure cut off switch should be used to stop the pump when the engine stops. This reduces the possibility of fuel pumping out if the car is wrecked. (also the reason NASCAR requires manual pumps) You can buy a switch that will provide the shutoff function as well as provide info for your oil pressure gauge.

Rubber mounting will reduce the noise of an electric pump.

Rubber fuel hose for the whole fuel line is not acceptable. Hardlines are recommended wherever possible. (although there are new flexible tubing systems you could check into designed for fuel injected systems)

Make sure you have rubber fuel line long enough to allow for movement of the engine somewhere in between the engine and where the fuel line or regulator is mounted to the body or chassis.

Use rubber mounted clamps to hold metal tubing in place along frame and body to allow for "flex". Also, if you do not a full frame car or have welded subframe connectors, make sure there is a rubber section of gas line where the subframe meets the unibody. Again to allow for flex.

If you run a return line from the regulator back to the tank make sure you have rubber hose sections in the same places to prevent stress cracks in hardlines from flexing.

When fabricating fuel lines make sure you have a good tubing bender to avoid kinks. If you kink a tube throw it out and make a new piece. Kinks really restrict flow and if you try to straighten them you will have a weak spot that can crack. Aluminum is much easier to bend up than steel. Cut sections of tubing longer than you need and work from one end to the other making bends and checking fit. Be patient!

The top pic below was taken while I was mocking up fuel lines for my system (so no clamps in place). I have the regulator located on the fenderwell so it doesn't get hot and fuel lines are away from the engine to reduce heat soak. The bottom pic shows the fuel filter on the left side and the bottom of the pump. I like to use the "fuel injection" hose clamps shown in the pic because they work better and don't grind into the rubber the way worm drive hose clamps do. "