Race Mustangs benefit from fuel cells similar to the one shown in this photo, mainly because they can hold a sufficient amount of fuel at a considerable weight savings. Primary fuel cells are usually mounted inside a 'Stang's trunk or hatch area, but Rick's Hot Rod Shop also makes a trick, pump-inclusive, supplemental tank for power adders that holds a higher-octane fuel and can be custom-made to fit a Fox, SN-95, New Edge, or S197 'Stang's engine compartment.
HP Performance offers this return-style fuel setup for all '87-'04 EFI Mustangs. The kit includes a sumped tank, a 1,000hp pump, a regulator, a 111/44-inch micron filter, a 131/44-inch micron fuel filter, fuel rails, pre-made lines, and all the necessary fittings and hardware. HP's fuel system is return-style with a rear-mounted regulator.
Fuel Lines
Fuel lines are probably the least thought-about components, yet they're among the most important pieces of a Mustang's fuel system.
There's no way a 'Stang's engine can run without fuel lines, because they shuttle gasoline between the fuel tank and the engine.
Most stock fuel lines are made of rubber or hard steel that's 31/48 or 51/48 inch in diameter. This size tubing is relatively small and doesn't support the fuel-volume needs of big-horsepower Mustangs, so upgrading to AN -10 (approximately 11/42-inch diameter) braided-steel hose is a common practice.
Setting up a Fox Mustang with 11/42-inch braided or high-pressure rubber fuel-delivery and return lines is recommended for power-adder-assisted setups. Braided hose is flexible, but it's also strong and can stand up to the vigors of extreme racing conditions and daily street use. Braided lines use AN fittings with bends of varying degrees. The fittings ensure positive, tight connections at the critical unions within a fuel system.
We spoke with Jonny Orme of Orme Brothers Hose and Fittings in Northridge, California, and asked for his insights on the approximate amount of braided line required for creating a typical return-style fuel system for a Fox Mustang. Here's the 42-foot breakdown for a 350-400hp street/strip fuel system:
AN -6/Return: 21 feetAN -8/Main Feed: 18 feetAN -10/Tank-to-Pump: 3 feet
This estimate may vary, depending on the level of custom the fuel system takes on or how far you deviate from the basic return-system layout. Keep in mind the shortest distance between two points is a straight line, so your 'Stang's fuel line should be laid out for maximum efficiency, not maximum flair. Intricate turns and routing of a fuel line looks nice, but it can become expensive as the AN fittings add up.
We've often been asked what the trick is for cutting braided hose. There isn't any magic in it at all. A chop saw or cutoff wheel will easily get through the thickest braided hose. The key to success is to wrap a small piece of masking or electrical tape around the end and cut in a slow, even fashion.
Don't take the term "chop" too literally when you're operating the saw. Smooth cuts will produce clean, non-frayed hoses. We also recommend a set of Koul Tools for assembling your fuel system's hoses and fittings.
Here's a look at the difference in the diameters of the three most popular braided hose sizes. From left to right are an AN -6 (return line), AN -8, and AN -10. The AN -8 line can be used as primary fuel feed to support as much as 500 rwhp, but its more common use is as a primary feed for 'Stangs that put out a maximum 350 to 450 horses. The AN -10 braided is mandatory for engines that produce 600 hp or better at the rear wheels. Fuel volume is much more critical for those applications.
Vapor lock occurs when part of the fuel system reaches a temperature above the fuel's boiling point while at idle, in stop-and-go driving, or after the engine is shut down. To avoid having this condition affect your 'Stang, make sure fuel lines are routed away from the exhaust or other heat-producing elements below the car or in the engine compartment, typically to the outermost side of frame connectors.