The engine in this Modified has a very typical high-volume aftermarket mechanical fuel pum
In order to get the fuel through the lines, most circle track race cars utilize an engine-mounted pump of some type. It may be located on the engine in the OEM position or it could be a beltdriven pump on the front of the engine or even an engine-mounted pump driven off the camshaft. It may take the form of a diaphragm, piston, or a gear-type pump. The amount of power the engine generates will dictate the type of pump utilized.
It's a fairly simple equation: The more power that the engine generates, the higher the need for a higher volume of fuel required. These types of high-volume pumps are usually found on engines running alcohol or very high horsepower gasoline engines. Some racers have opted to remove the mechanical fuel pumps and use electric pumps.
This is an OEM-style fuel pump for a small-block Chevy engine. There are literally hundred
However, not all sanctioning bodies allow electric pumps. Due to the potential of the car being involved in a crash, the potential for fire is increased if a fuel line is damaged and the pump continues to run. While a very specific set of circumstances have to occur for this to play out, the risk is there and some racing organizations aren't willing to take that risk. Even so, there are many race cars racing safely that are using electric fuel pumps.
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.
This is a high-performance mechanical pump offered by Holley. It offers higher operating f
However, nothing says you can't do both. Place filters between the tank and the pump that have a larger media that may not be as restrictive and use a filter between the pump and the carburetor that has a much finer media that captures smaller particles that may be in your fuel. Another advantage of placing a filter in front of the pump is that it keeps debris from possibly damaging the pump, especially if you're using a positive displacement mechanical pump that uses gears as opposed to a diaphragm-type of pump. If you have a high-dollar fuel pump, you will want to prevent any sort of debris from making it from the tank to the pump, possibly damaging the pump.
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.
It doesn't matter if you're running a Bomber stock and the rules allow you to run the OEM
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.
There are no magical or mystical things about fuel systems. The components are easy to understand and the execution of constructing a good fuel system is something that is easily accomplished. A well-engineered fuel system is just that, a system for delivering winning performance and dependable operation in all racing situations.