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Fuel System Basics

Written by on March 9, 2011 Tips, Tricks, And Knowledge For The Entry-Level Racer
Fuel System Basics View All 14 Photos


Ctrp 1105 01+fuel System Basics 2/14 The trick is to get the fuel from the tank located in the rear of the car to the engine in the front. Simple? Consider that the car will go through a number of angle forces and the g-forces while racing, both of which impact the fuel system.



Ctrp 1105 02+fuel System Basics 3/14 Sunlight can cause a rapid degradation of a fuel's chemistry. While the use of white plastic or translucent fuel containers may be fine for alcohol, gasoline should be transported in containers that prevent sunlight from reaching the fuel, like these blue ones.


Buying Fuel
Regardless of the system's complexity, it all begins with the point where you, the racer, buy your race fuel. This is a critical point in the fuel system that's often never given a second consideration, but it's just as important as any part of the fuel system on the car. It's at this point that racers begin to really control the fuel system, and we all know that racing is all about control.



Ctrp 1105 03+fuel System Basics 4/14 A couple of typical engines used in a Saturday night racer. Both use the engine-mounted mechanical fuel pump. However, the motor in the this car uses an inlet line that attaches to a fuel manifold (red) hose that feeds the carburetor.



The containers should be either metal or an opaque plastic. If you're using plastic fuel cans and you are transferring gasoline, the best color is black. Translucent white fuel containers may look cool and may be the rage, but they aren't the best selection for the transportation and storage of fuel. You may be paying a price in diminished performance of the fuel for that cool look in the pits.

Ctrp 1105 07+fuel System Basics 8/14 This type of filter is great for the daily driver since it allows you to see into the filter and look for any foreign matter. But it's not made for racing and shouldn't be on your race car.



You need to remember that your fuel containers are really consumable items just like tires. They do not last forever and still wear out. If you're using plastic fuel containers, inspect them regularly for cracks around the container and cap/vents. When you find a crack, replace the container. And even if you don't and the container is several years old you should still replace it. If you are using metal containers you need to be on the lookout for rust in the can and around the fill points. Attention to small details is what separates the winners from the field fillers.

Ctrp 1105 08+fuel System Basics 9/14 An inline metal filter with a removable, washable element will serve you well, allowing you to simply remove the filter, clean and inspect it, and then reassemble the unit. The metal housing protects the system from on-track debris striking the filter and becoming a potential for leakage.


Tanks & Cells
Once the fuel reaches the tank we still need to be very conscious about keeping the fuel clean. Fuel cells don't last forever, the foam that's inside the bladder can break down over the course of a season or sooner depending on the fuel you are running. Some race fuels are very unkind to synthetic rubber products over time. If this happens the fuel will be contaminated by the foam and can cause some real fuel system problems. The foam should be replaced at the intervals sug-gested by the fuel cell manufacturer.

Ctrp 1105 09+fuel System Basics 10/14 Fuel-pressure regulators are available in many different types and brands that can be matched to your specific system's needs and budget. As you develop more power and the pressure developed by your pump has the ability to blow the inlet needle off the seat on the carburetor, you'll need to install a fuel pressure regulator. If you run an electronic fuel-injection system, a fuel-pressure regulator will be a necessity, not an option.


Getting the fuel from the cell or tank is accomplished with the fuel lines. If you're utilizing the OEM fuel lines, they're usually made up of a combination of hard lines made of steel or flexible steel lines and rubber or neoprene hoses. Steel lines are usually very durable. The caution point, if you're racing in a Street Stock-type of class, the OEM fuel lines, while very durable, are not designed for race cars. The elevated level of maintenance racers perform may cause wear and tear on the various components of the fuel lines, especially the fittings and threaded joints. You need to make sure that the fuel lines are routed in such a way that they are securely mounted to the chassis and are protected from any debris or errant broken part you may encounter on the track. If you have rerouted the fuel lines you need to make sure that the fuel line will not be in the way of any suspension parts that at their full range of movement could impact or rub on the fuel line. If you're running the fuel lines through the passenger compartment, most racing organizations require that the line be run through a section of steel tubing that will isolate the fuel line from leaking into the driver's compartment.


Ctrp 1105 10+fuel System Basics 11/14 The engine in this Modified has a very typical high-volume aftermarket mechanical fuel pump that is fed with a larger-than-OEM fuel line, and there's no fuel pressure regulator in this system. It's very simple and gets this job done.



Ctrp 1105 11+fuel System Basics 12/14 This is an OEM-style fuel pump for a small-block Chevy engine. There are literally hundreds of millions of these pumps in service all over the world and there have been a good number of very successful Saturday night racers who have used this exact style pump in their cars. However, it's not really the best option for the weekly racer, especially if he or she has an engine capable of elevated rpm and hp.

You naturally need a filter for all this fuel traveling to the motor, but do we want the filter between the pump and the tank or between the pump and the carburetor? Filters placed between the pump and the tank, allow the use of larger filters in line. Mounting them to the chassis where they're out of the way makes them potentially more difficult to service. Or we can place the filter between the pump and the carburetor. This option has some advantages, such as making it easier to work on and if it's easier to work on, odds are that it will get serviced more often. Is there any one method that's better between the two options? Can't say for sure, but if you have a limit to the amount of fuel you can carry, placing the filter(s) between the tank and the pump allows you to use a larger filter to gain some fuel capacity.


Ctrp 1105 12+fuel System Basics 13/14 This is a high-performance mechanical pump offered by Holley. It offers higher operating flows and pressure than the OEM pump, is tunable, and is designed to be disassembled so you can check the pump mechanism, the diaphragms, and the check valves.

The next thing we need to consider is the pressure of the fuel at the carburetor. With an engine that is closer to the power levels of the OEM engine, fuel pressure is less of a concern than with a highly tuned engine. Along with a pressure regulator you'll also need a fuel-pressure gauge. Using a fuel-pressure gauge will allow you to measure the fuel pressure. The regulator needs to be mounted between the pump and the carburetor and depending on the type of regulator you may need to run a return line to the tank. The pressure gauge is one tool that you can't do without if you're running a fuel pressure regulator. With the gauge you'll always know the exact pressure you're getting at the carb. Remember, delivering too much fuel can cause just as many problems as not enough fuel. Being able to measure your fuel pressure gives you one more parameter to help you tune the car.

The gauge should be able to be read from inside the car while it's at speed. With that said, in the interest of safety, try to utilize a fuel-pressure gauge that utilizes an electronic sending unit so you don't have to run a fuel line into the driver's compartment.

Ctrp 1105 13+fuel System Basics 14/14 It doesn't matter if you're running a Bomber stock and the rules allow you to run the OEM fuel tank, you should be running a proper racing fuel cell. The stakes are just too high to not take the safest route. Plus fuel cells give you the ability to create a more efficient, integrated fuel system.


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