Understanding AN Fittings and How They Improve Performance Plumbing

AN fittings are a critical part of any high-performance fuel, oil, or coolant system. Whether you are setting up a drag car, circle track engine, dirt track build, or a high-performance street vehicle, AN fittings provide the strength, reliability, and durability needed for leak-free operation. At Fastime Performance in Taylor, Michigan, we stock a complete selection of AN fittings and hose options for all types of builds.

What Are AN Fittings?

The term "AN" stands for "Army-Navy" and originates from early military specifications used in aircraft. Today, AN fittings are a motorsports standard thanks to their secure sealing, threaded connection design, and ability to handle high pressure and high temperatures. They also allow builders to assemble and disassemble lines easily, making service and upgrades much more efficient.

Understanding AN Sizes

AN fittings use a dash number system to indicate hose size. Each dash number represents the hose diameter in sixteenths of an inch.

• -4 AN = 4/16" (1/4")
• -6 AN = 6/16" (3/8")
• -8 AN = 8/16" (1/2")
• -10 AN = 10/16" (5/8")
• -12 AN and larger for high-flow or specialized use

Most fuel systems use -6 or -8 fittings, while oil and coolant systems often require -8, -10, or -12 depending on flow needs.

Types of AN Fittings

AN fittings come in several configurations to help route plumbing cleanly around engine components. The most common types include:

Straight AN Fittings

These are used when components are aligned directly. They provide the simplest and most direct connection.

Angled AN Fittings (45°, 90°, 120°, 180°)

Angled fittings help route hoses around obstacles, brackets, engine accessories, and tight spaces without stressing the hose.

Bulkhead Fittings

These allow plumbing to pass through panels, firewalls, or tanks while maintaining a strong, sealed connection.

AN to NPT Adapters

Many components (fuel pumps, regulators, filters) use NPT pipe threads. AN adapters allow you to connect braided hose systems to traditional threaded parts.

Material Differences

Most AN fittings are made from either anodized aluminum or stainless steel.

Aluminum AN Fittings

Lightweight, corrosion-resistant, and available in several finishes. Ideal for most fuel, oil, and coolant systems.

Stainless Steel AN Fittings

Used when extreme strength or chemical resistance is required, such as brake lines or high-pressure oil systems.

Hose Types: Rubber Core vs. PTFE

Selecting the right hose for your AN fittings is just as important as the fittings themselves.

Rubber Core Braided Hose

Flexible and easy to assemble. Works well for fuel, coolant, and oil lines but must be rated for ethanol if used with E85.

PTFE (Teflon) Hose

More rigid but extremely durable. Recommended for high-temperature, high-pressure systems, or when running E85, transmission fluid, or brake fluid. Requires PTFE-specific hose ends.

Why Builders Choose AN Fittings

AN fittings offer several advantages that make them the preferred choice for performance plumbing:

• Superior sealing under pressure
• Reusable and serviceable design
• Resistance to heat, vibration, and chemicals
• Clean, professional appearance
• Easy routing in custom engine bays

For race engines, show cars, or serious street builds, AN fittings deliver the reliability and performance needed to protect your engine investment

Shop AN Fittings at Fastime Performance

Fastime Performance carries a full line of AN fittings, braided hose, adapters, and performance plumbing accessories. Whether you are setting up a fuel system, adding an oil cooler, or upgrading coolant lines, we can help you find the right components for your build.

Visit our shop in Taylor, Michigan or call (734) 947-1600 for assistance in choosing the right AN fittings and hose combinations for your project.