Fuel filters for high performance or all-round racing have a bigger role than many realize. We’ve seen dozens of riders use a filter-in-a-funnel-style filter on the trail and call it “pretty good.” Fuel pumps, electronic injectors, carburetors, sensors, etc. Today’s fuel filters continue to tighten their tolerances to achieve better fuel delivery to meet higher horsepower demands, and fuel filters must step up their game to protect these components.
Flow Criteria for Filters
The overall flow of a fuel system is only as good as the combination of components and how they feed or flow your fuel supply. We fitted the Project Rover Camaro with a pair of Fuelab inline filters for our E85-powered electronic fuel injection system. Brian Paitz, President of Fuelab, gave an overview of proper filtration for a racing or extreme performance fuel system.
“The one thing I can’t stress enough when you’re setting up a fuel system is that you think of it as a complete system,” Paitz begins. “It goes beyond just a pump, it goes beyond the regulator – it has a lot to do with your filters too.”
Filter size and location
The success of feeding your engine for its maximum fuel demands will greatly depend on two critical places in your filtration: filtering the fuel before and after the fuel pump is the most efficient arrangement. These two filter points ensure that your fuel system is optimized for flow, while being protected.
Fuelab offers a variety of paper/cellulose, fiberglass, and stainless steel filter choices that best apply to your filter size and fuel type. In their store they showed two branded fuel pump plates next to the originals which demonstrated the result of not using proper filters before and after your fuel pump.
Basically, we specified our in-tank fuel pump at 150 gallons per hour (GPH). With that, we researched the Fuelab GPH filter offerings and chose the 818 series inline fuel filters, which can handle 200 gph. These feature male 37 degree flare fittings on both ends and can be ordered with different size combinations on male inlets and outlets -6AN, -8AN, -10AN or -12AN.
Paitz explains that you need to choose the size of the filter to avoid pressure drops. “You want to be sure you’re getting a pump filter that can handle the capacity of fuel coming out of the pump,” he says. “You want to minimize the pressure drop across the filter. Blowing 10 gallons per minute through a filter that has a -6AN inlet and outlet will create a pressure drop across that filter, potentially losing a few pounds of pressure.
Our EFI system dictated our remaining pipe sizes; it requires -8AN inlet pipe and -6AN return line. We took advantage of Fuelab’s unlimited combination of AN fittings at the inlet and outlet ports of the filters to connect a -10AN filter inlet from our pump to a -8AN filter outlet to our EFI system, and a return filtered -6AN to the tank.
Apart from our selection, Fuelab also offers filters in larger sizes. The 828 series inline filters have the same diameter as the 818 filters we use, but contain a 5 inch long filter element compared to the 3 inch filter of the 818 models. The 828 series supports a flow rate of 350 gph.
Their new 868 PRO Series Extreme Flow Inline Fuel Filters are rated at 10 GPM for maximum flow and minimum pressure drop. Wait, GPM? Yes, this filter will deliver 10 gallons per minute with male -10AN inlets and outlets and a 5 inch diameter filter element.
They put the word “laboratory” in the company name at Fuelab for a reason: their extensive testing equipment helps develop the highest internal flow characteristics to avoid low pressure points in filters. Their 3-inch fiberglass, 5-inch paper/cellulose, and 5-inch stainless steel filter media are featured.
Filter media and fuel type
Fuelab offers several choices of filter cartridges to insert into your filter housings. “We recommend using a 100 micron or finer filter before any performance-type pump,” says Paitz. “Having the correct size pre-filter before the fuel pump is very important. This stainless steel filter element should only be used as a pre-filter for fuel pumps – it helps prevent pump cavitation with extremely low pressure drop.
A finer element (lower numerical rating in microns) is recommended directly after your fuel pump to protect injectors, carburetors and other downstream components such as fuel sensors. There are a variety of filter media choices; the decisive factor is the type of fuel used.
A numeric rating describes the capabilities of a filter. For example, a 100 micron filter will stop a particle as small as 100 microns. Our glass microfiber element provides extra protection by removing particles down to 6 microns. –Brian Paitz, Fuelab
Filter Media Choices
The Fuelab stainless steel filter is available in 40 and 100 micron filtration levels and is compatible with gas, diesel, ethanol and methanol. In addition, the stainless steel filter is cleanable and does not necessarily require replacement for maintenance.
“Our 100 micron cellulose paper element is economical and commonly used as a pre-pump filter element, but can only be used with gasoline and diesel fuels,” says Paitz. “Our most advanced filter is our microfiber glass element – it provides added protection against particulates with improvements in filter efficiency. This disposable element is compatible with gasoline, diesel, ethanol and ethanol. methanol.
The filter housing offers a threaded cap allowing access to the filter area. Paitz shows us a fiberglass media filter that has done its job of filtering E85 to the point of crumbling. He told us that this customer hadn’t replaced his filter in over two years.
Our E85-powered Project Camaro has a fuel recirculation system that uses a return line to the pump in the tank. We installed Fuelab’s 100 micron stainless steel filter before the tank return line inlet and their inline filter with a 6 micron fiberglass element directly after the pump outlet.
One curveball Paitz cautioned about with cellulose/paper filters is the use of oxygenated fuels. Even if you run on gasoline or diesel, if that fuel is oxygenated, definitely choose the microfiberglass option.
If you use the stainless steel mesh filters at one or more locations, cleaning and reusing these filters is relatively easy. Scrubbing with carburetor cleaner, catch pan, and compressed air will do; we take it a step further and use a parts cleaning toothbrush and a small ultrasonic cleaner in our filter maintenance.
Another option is the non-return valve (arrow) integrated into the housing. This allows the benefits of your fuel system to remain under pressure when your fuel pump is not working. Their pumps, filters and regulators are anodized to military standard MIL-A-8625 with high-tech laser engraving of your product and serial number on the housing.
It’s wise to make sure you have spare Fuelab o-rings in your toolbox in case one gets damaged when disassembling the filter housing. For paper/cellulose or fiberglass filters, there is no recleaning option. All of Fuelab’s replacement filters come with spare fluorosilicone O-rings.
Additional Features
All Fuelab filters are machined from billet aluminum and finished with durable fuel anodizing to military specification MIL-A-8625 (Type II). They are available in a variety of anodized colors.
The filter housing is designed with internal radius points machined along the internal flow of the filter housing from inlet to outlet. These rounded arrangements allow for minimal pressure drop in the fuel flow. An internal spring forces the filter against the downstream port of the housing to seal it; this causes fuel to travel through the filter from the outside to the inside.
Inside you can see the extensively developed flow radius corners which provide the best flow figures. An internal spring forces the filter element onto the outlet port where all fuel moves from the outside of the media to the inside for better flow. An output indicator is machined into the housing.
For Fuelab’s 848 and 858 series filters, there is a built-in check valve option that allows your fuel system to maintain fuel pressure when the pump is idle. The compact valve is located at the outlet port of the filter for protection against contaminants and easily relieves the use of an external check valve in some systems.
We are protected
With a 100 micron and 6 micron filter fitted to our recirculating fuel system, we are confident that no contaminants in the fuel will affect our electronic fuel injection or damage our fuel pump. Paitz finished by adding his recommended maintenance schedule.
The “beast” of a filter from Fuelab is the 868 PRO Series Extreme Flow Inline Filter. With a 6 inch filter length, it can flow a whopping 10 gallons per minute with -10 AN fitting ends.
“So people ask me how often do I need to change the fiberglass filter? For drag racers, make it a once-a-season filter inspection, as well as a deep cleaning of the stainless steel filter. But there are so many variables, like where do you get your fuel? Does it fit in a storage tank? Is it E85? Do you filter the fuel before putting it in a cell? These variables should prompt you to consider a stricter inspection and maintenance schedule.
As you consider the many gallons of fuel that pass through your race fuel system, keep in mind how quickly particulate matter or even the slightest degradation in your fuel lines can affect your fuel system. Think of these quality filters as a protective component for your fuel system and monitoring devices to inspect which tiny, micron-sized “hitchhikers” are corrupting your performance carbs or injection system .
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