Fuel System

This section covers the plumbing that moves fuel, and often oil, around a performance car:

• AN fittings, hose ends, and braided and PTFE-lined hose;
• banjo fittings and bolts, blanking plugs and clamps;
• catch tanks and reservoirs, and fuel filters;
• pressure regulators, pumps, injectors and tanks.

Most fittings here follow the AN system, a 37-degree flare sized in sixteenths of an inch, so -6 means 6/16 inch and -8 means 8/16 inch. The product data gives the AN size and thread. Choose the size for the flow the line has to carry. Then pick the adapter that joins it to the port on the part, which may be metric, NPT, BSP or UNF.

The shapes and materials on offer:

• Hose ends: straight, or angled at 45, 90, 120, 150 or 180 degrees, some for push-on hose.
• Adapters: male, female, swivel, T, Y or reducer.
• Materials: mostly anodised aluminium in black, blue or silver, with stainless steel, brass and plastic versions for particular uses.

Match the hose to the fluid. PTFE-lined hose suits modern fuels, including ethanol blends, while rubber-lined hose may not; push-on hose must be used with push-on ends.

Assemble each end carefully and pressure-test the system before running the engine. Route fuel lines away from exhaust heat and moving parts, fit filters where the pump and injectors need them, and set the fuel pressure with a gauge. A larger pump or injectors will need matching changes in the engine calibration.