Everything You Need to Know About DASH AN Fittings and Hose Sizes

Everything You Need to Know About DASH AN Fittings and Hose Sizes

AN (Army-Navy) fittings and hoses were originally developed for the U.S. military to standardize flexible hose and metal fitting systems. Today, the AN standard is widely used in motorsports and automotive tuning, especially in high-pressure oil, fuel, coolant, and air systems. AN fittings provide a leak-proof connection without the need for additional seals due to their 37-degree flared design.

AN Sizes and Applications in Motorsports

AN fittings are sized according to the DASH system, where each number represents increments of 1/16 inch (1.5875 mm). The most commonly used AN sizes in motorsports range from AN3 to AN12. Smaller, odd-numbered fittings like AN3 are often used in brake and clutch systems, as well as turbo oil lines, while even-numbered sizes such as AN4, AN6, and AN8 are typically found in fuel and oil systems.

AN Sizes and Applications:

AN3: 3/16 inch (~4.76 mm), typically used for brake and clutch systems, and turbo oil lines
AN4: 4/16 inch (~6.35 mm), for oil and fuel systems
AN6: 6/16 inch (~9.52 mm), for fuel systems requiring higher flow rates
AN8: 8/16 inch (~12.7 mm), for high-performance oil systems or fuel lines
AN10: 10/16 inch (~15.88 mm), ideal for high-pressure oil systems
AN12: 12/16 inch (~19.05 mm), for high-flow oil lines

AN Hose Inner Diameters

The threaded portion of AN fittings is larger than the hose’s inner diameter, ensuring that the fittings fit securely and operate reliably under high pressure. For example, a -4 AN fitting has a threaded diameter of 6.35 mm, but the associated rubber or PTFE hose will have a smaller inner diameter.

AN Hose Inner Diameters (Rubber and Teflon Hoses):

AN3: 3.302 mm
AN4: 5.588 mm
AN6: 8.636 mm
AN8: 10.922 mm
AN10: 14.224 mm
AN12: 17.526 mm

Types: PTFE (Teflon) and Steel-Braided Rubber Hoses

AN hoses are available in two main types: PTFE (Teflon) hoses and steel-braided rubber hoses. Both are widely used in motorsports and tuning, with different advantages based on the application.

PTFE (Teflon) Hoses:
The inner layer of PTFE hoses is made of Teflon, which provides excellent chemical and heat resistance, making it ideal for high-pressure systems such as brake and oil systems. PTFE hoses can typically withstand operating pressures of up to 290 BAR (4205 PSI). Due to their excellent chemical resistance, these hoses are also ideal for use with ethanol (E85) fuel, which can have particularly aggressive effects on traditional rubber hoses.
Their outer layer is often made of stainless steel braid, providing additional protection against wear and increasing pressure tolerance.

Steel-Braided Rubber Hoses:
Steel-braided rubber hoses are more flexible than PTFE hoses and are less resistant to chemicals, but they are ideal for lower-pressure systems, such as fuel systems. These hoses can typically withstand operating pressures of 69 BAR (1000 PSI).

The 37-Degree Flared Design of AN Fittings

One of the biggest advantages of AN fittings is their 37-degree flared design, which allows for leak-proof connections without the need for additional seals. This design ensures that fittings fit tightly together, providing reliable performance even at 600-1000 PSI (41-68 BAR) pressure. This is especially important in motorsports, where high-pressure fuel and oil systems must operate safely and efficiently.

Installation Steps:

Precise cutting: Use a precision hose cutter to ensure a clean, smooth surface on the hose
Fitting assembly: Insert the fitting into the hose and tighten the nut to ensure a secure connection
Pressure test: After assembly, perform a pressure test to ensure the system is completely leak-proof

Why Choose LLRacing.eu?

At LLRacing.eu, we offer a wide selection of AN fittings and hoses that meet all motorsport and tuning needs. Whether you need parts for your brake, clutch, fuel, or oil system, you’ll find the right size and material to ensure your vehicle’s maximum performance and reliability.