Fittings

Tuning and motorsport demand precision, high-performance components and reliability. Every part of the vehicle, from the engine to the brakes, has to cope with extreme conditions. Among the most important parts of these systems are fittings and hoses, which play a key role in transferring fluids, whether it is fuel, oil or coolant.

The AN designation comes from the term Army-Navy. These fluid connection and plumbing systems were developed during the Second World War to provide maximally robust fluid transfer in the harshest conditions. To this day they are used everywhere from aircraft and military equipment to motorsport. The AN size defines the hose diameter and the fitting size, designated as AN-2, AN-3, AN-4, AN-6, etc.

AN-3: 3/16 inch (4.8 mm)
AN-4: 4/16 inch (6.4 mm)
AN-6: 6/16 inch (9.5 mm)
AN-8: 8/16 inch (12.7 mm)
AN-10: 10/16 inch (15.9 mm)
AN-12: 12/16 inch (19.1 mm)
AN-16: 16/16 inch (25.4 mm)
AN-20: 20/16 inch (31.8 mm)

Why use AN fittings and hoses?

Fittings offer a high degree of reliability because they withstand high pressures and temperatures, which is critical for motorsport applications. At the same time, their compatibility offers modularity, which makes installation and system modifications easier. The fact that they are made of aluminium, steel or stainless steel also makes them an ideal component for custom work, where they can be welded onto other parts and then connected up. These materials also guarantee high resistance to corrosion. The hoses are protected by several layers of stainless steel braiding, which prevents damage, and that is why they are also used by many car manufacturers.

Unlike metric parts, these connections do not seal on the thread or on a flat seating face. Fittings have a 37° seating face on the mating pieces, so once tightened the connection forms a leak-proof joint. That is why there is no need to use a copper washer or any kind of thread sealant when installing them.

Types of hoses

Hoses are chosen depending on the fittings used and also come in AN sizes.

Rubber hoses - the most common type of hose, used in all types of vehicles, mainly for transferring fuel, oil or coolant. Better suited to lower pressures and less aggressive fuels. Over time, cracking and possible damage can occur, as there is no braiding to protect the hose. This hose is suitable for fittings designated "Push Lock" (a push-on fitting combined with a conventional hose clamp).
Braided rubber hoses - the same as the rubber hoses above, but with an added outer PVC or stainless steel braid that provides maximum protection against mechanical damage. This hose is suitable for fittings designated "Push Lock" (a push-on fitting combined with a conventional hose clamp) or for standard fittings, where the hose is clamped between the fitting's socket and body.
Teflon hoses (PTFE) - a hose made of durable Teflon, which resists chemicals, oils and aggressive fuels. The ideal solution for top-level motorsport, where maximum durability is the priority. The Teflon is protected by a stainless steel braid against external damage. This hose is suitable for fittings designated PTFE, which are equipped with an aluminium or brass "olive" that is pressed into the hose as the fitting is tightened, preventing the joint from coming loose even under high pressure or temperature.
Hardline - an aluminium tube resistant to every kind of fluid and to high pressure. Also suitable for external use, where the appropriate hardline fittings need to be installed. In motorsport it is most often used for fuel, oil or brake fluid lines. In production vehicles these tubes are also found in air-conditioning lines.

Types of fittings

Fittings are chosen according to the application, together with the need to use a suitable hose.

Push lock - easy to install by pushing on, in combination with a hose clamp. Suitable for low-pressure applications. For use with rubber hoses.
Standard fitting - used with braided rubber hoses in AN sizes. Suitable for higher pressures, with simple installation by clamping the hose as the fitting's socket is tightened. No special tools or skills are needed for installation.
PTFE fitting - the most durable type of fitting, used in combination with a Teflon hose. Suitable for high-pressure installations. The fitting works by pressing the so-called olive into the hose as the fitting's socket is tightened. This creates a durable joint, which is, however, single-use. To reuse the fitting, you need to buy a new inner compression "olive".

All of these fittings are offered in various angles and colours, with the option of connecting them via various fitting unions and adapters. Every installation has its solution through the right combination of fittings and hoses.

How to choose the right size?

The size depends on several factors, such as flow rate, pressure and temperature, as well as the space where the line is to be installed.

Fuel system - AN-6 or AN-8 is often used for fuel flow in high-performance engines. Production vehicles mostly have diameters of 6 to 8 mm, which is the equivalent of AN-6.
Oil system - AN-10 is ideal for oil coolers and the vehicle's lubrication systems. The ideal compromise between size and high flow rate.
Cooling system - AN-16 and AN-20 are used for coolant, especially in vehicles built for drifting, where the radiator is mounted at the rear.
Brake system - AN-3 in combination with Teflon hoses is the most widely used size in both road and motorsport cars
Clutch system - AN-4, just like the brake system in combination with braided Teflon hoses, is the right size for the clutch system to work properly

Special fittings

Fittings also offer the advantage of various external connections into the system, as well as other benefits that a conventional hose connection does not allow.

Sensor connection - fittings that allow you to connect a sensor without having to disconnect the system. This also helps when there is not enough room at the point where the sensor is required. You can then connect the sensor at a more distant point using the appropriate fitting.
Weld-on fittings - if your vehicle does not have an AN-sized outlet, you can use weld-on fittings, available in three different materials: aluminium, steel and stainless steel.
Quick-release fittings - used mainly in top-level motorsport. They allow you to disconnect the system in the event of an accident or when replacing the connected system, without needlessly draining the fluid. Once disconnected, the fitting closes, preventing fluid leakage, so there is no need for topping up or bleeding.
Snap-on fittings - new in our range - fittings that allow you to disconnect the fitting body without having to disconnect the hose or unscrew anything. Instant disconnection guarantees a quick system change or replacement with another, with the option of immediate reconnection. The connection is perfectly sealed by rubber O-rings.

AN fittings and hoses are indispensable for motorsport and for applications in extreme conditions. Their modularity, durability and wide range of uses make them the ideal choice for anyone looking for reliable solutions for their vehicle. These systems offer a fast and effective solution for transferring every type of fluid and air in a vehicle, an aircraft or other industries.

If you need advice on choosing the right hose or fitting for your application, do not hesitate to contact us.