It could have something to do with those pesky steel splinters that always impregnate themselves in your skin. Or maybe it has to do with man's natural aversion to forking over stacks of greenbacks so tall in height for products so diminutive in size. Whatever your own personal prejudice may be, no one likes plumbing. Nonetheless, proper fluid transfer keeps your motor from going poof, and keeps your car out of the sand trap. Considering the dire consequences of getting it wrong, it only makes sense to get your plumb job done right the first time. To help us accomplish this, we hit up Kevin Cochran of Earl's Performance Plumbing. High-performance plumbing has come a long way in recent years, so it's time to get up to speed. Equipping yourself with the knowledge to properly select components, size and route lines, choose the right tools, and install fittings will ensure your fluids stay off of the pavement and in your car.

Origins Of AN Fittings
"The AN (Air Corps/Navy) standards were established prior toWW II in order to organize and standardize the sizes, configurations, and specifications of military aircraft hardware into a service-wide system of interchangeable parts," Kevin explains. "Due to its simplicity and effectiveness, the system soon became industry-wide. With respect to plumbing, the number that we usually refer to as the AN number is actually a size designation and comprises only a small part of the full AN identifying number. It is properly referred to as the AN dash number, and does not define the inside diameter of a flexible hose. Instead, it refers to the outside diameter, in increments of 1/16 inch, of the metal hard line that is considered to be its equivalent in flow. The hard line outside diameter was used as the standard simply so that the metal flared tube compression sleeves and coupling nuts used with the hard lines could be standardized."

Hard-90s
If everyone knows that 90-degree turns should be avoided when plumbing a fuel or brake system, it's probably because that bit of advice is a widespread myth. "This is only true when you can use a straight, 30- , 45-, or 60-degree fitting and choose to use a 90-degree fitting instead," explains Kevin. "Earl's second-best selling hose end is our swept tube Swivel Seal 90, a design that yields tremendous flow through the entire fitting. Also, our straight-to-low-profile 90-degree brake fitting assemblies are our second most popular configuration. Contrary to popular belief, 90-degree hose ends are an essential part of plumbing any vehicle."

Hose Routing
Although it seems like common sense, bending hoses should be avoided whenever possible. "The number-one issue with plumbing we find is that people do not use all of the configurations of hose ends at their disposal when making assemblies," explains Kevin. "They need to let the hose end route the hose, not use straight hose ends and bend the hose, which is the reason why we offer so many different degree bends. Hose is for taking fluid from point A to point B without getting it on the ground and without considerable pressure drop. Use the different degrees of hose ends available to you to accomplish this in your routing."

Quality Control
To maintain top-notch product quality, Earl's has always used aircraft-quality raw material and manufactured its own parts in-house. It is all domestically sourced to control the quality demanded in racing applications. "Rigorous testing is very much part of our manufacturing process," explains Kevin. "We still pressure-test every brake line that leaves our building at 4,000 psi. We periodically test hose assemblies to the point of failure to ensure that the quality standards of the parts are being met. Our warranties amount to less than 1 percent annually, and for the number of parts Earl's ships per year, this is a testament to making a quality part from the outset."

Stainless Fittings
Due to advances in fitting technology, aluminum hose ends can now be used in applications once reserved for stainless steel hose ends. However, there is still a time and place for both. "With the advent of more sophisticated plating in performance plumbing-like Earl's Ano-Tuff and Ultra-Flex hose ends-aluminum can be used in the same environments in which stainless was necessary in years past," says Kevin. "The obvious benefit of aluminum over steel is weight savings. Stainless steel has mostly been relegated to brake line and turbo systems due to their superior structural integrity and resistance to heat."

AN Advantage
Plumbing up your ride with AN hoses and fittings is a costly affair in anyone's book, but there's a reason why racers endure the expense. "Earl's designs the majority of our parts for racing, so you are actually buying the same parts that race all around the world every week," says Kevin. "If you buy our Ano-Tuff hose ends with stainless hose or nylon fiber hose, you have a much better assembly than OE lines or what's available at your local parts store. This is due to the longer thread life of the Mil-spec Type III, Class 2 plating on the hose ends, and our high-flow synthetic rubber armored hose. It survives longer in harsher environments than a standard hose assembly, and let's face it, it just looks a hundred times better than OE lines."