Power Hose

Miles of braided stainless steel hose adorn the vehicles used to both orbit the earth and win races upon its surface. Braided-hose technology has been around for decades. First used for high-pressure hydraulics on heavy machinery and then on aircraft, there isn’t a single jumbo jet flying today that doesn’t rely on braided hose to keep it aloft. NASA engineered all of its manned and unmanned spacecraft using braided hoses to survive in outer space. There’s even a mil-spec on the types of hose and fittings that can be used by all military contractors. So if all these agencies, which can afford to buy anything they want, rely so heavily on braided-hose technology, shouldn’t you?

Race cars are routinely equipped with braided hose to protect against leakage caused by abrasion and collision. NHRA rules allow no more than 12 inches of exposed rubber hose over the entire length of the fuel system. NASCAR won't allow any exposed rubber hose at all. The only acceptable alternative, then, is braided hose.

Stainless steel braiding is the most common as well as the most expensive replacement, but recent advancements in hose-covering technology has developed new, lighter hoses using alternative coverings such as nylon. New products such as the Pro-Lite hose from Earl's weighs considerably less than comparable stainless hose, yet has equal working pressure limits and will work with most existing Earl's fittings. Some of the earlier lightweight hose designs required special fittings, which translated into a big expense for teams in exchange for saving a few precious pounds.

AN Fitting Technology

The U.S. armed forces have employed outside contractors to build equipment to their specifications for years. The acronym "AN" comes from the term Army/Navy and, to keep up with the ever-increasing demands placed on hydraulic equipment in battle, engineers devised certain parameters that any product must meet. The moniker "AN" was used to describe both the steel braided hose and aluminum fittings that transcended the military world into the automotive aftermarket over a period of years. The first AN hose and fittings used on a race car were probably some discarded aircraft equipment stripped from a decommissioned plane and sold to an eager racer at a fraction of its original cost. Although the armed forces still use equipment that employs AN fittings and hose, this technology can be seen more readily on the streets and racetracks nationwide.

There are currently two types of fittings used on cars today: SAE and JIC. Every stock hose and fitting from the major auto manufacturers, with the exception of a few power-steering hoses, comes with an SAE standard, 45-degree flare on its end. All AN fittings incorporate a 37-degree JIC flare. The letters "JIC" stand for Joint Industry Council, which developed the standards for aircraft hose technology early in the 20th century. The reason for the 37-degree flare was simple. The JIC didn't want any automotive hoses or fittings to cross over to aircraft applications. This would prevent unsafe cost-cutting that might jeopardize aircraft safety. If you're building a car that combines AN hoses and fittings with custom-bent hard lines, be sure to use the correct 37-degree flaring tool on any intersecting fittings.

Hose Technology

The braiding used to cover AN hose was designed to protect it from abrasion and provide the maximum pressure capabilities. The working and burst pressures of AN hose are determined by the make-up of its internal layers. Usually constructed of several overlapping layers of rubber and nylon or stainless steel inner braid, most AN hose with a stainless steel outer braid can withstand sustained working pressures up to 250 psi and maximum operating pressures around 1,500 psi.

Ironically, that great-looking braided stainless steel hose covering is also very abrasive to the components surrounding it and has been known to wear holes in aluminum tubes and scratch even the hardest polished surfaces. For those plumbing a race car with lengths of braided stainless hose, there are various ways to cover the hose and protect its surroundings.

Earl's offers Ruff-Stuff hose, which is simply its Perform-O-Flex braided stainless steel hose with a thin rubber covering. Another popular option, and one that's used often in extreme racing circles such as Winston Cup, is Earl's Flame Guard hose covering. As the name implies, this covering can operate around 500-degree-F parts all day long and withstand splashes of hot oil up to 2,000 degrees F. It can be slipped over any size AN hose, from -3 to -20, and will save the hose from hot exhaust while saving surrounding parts from the hose at the same time.

Power Steering Hose Is Different

Although you've probably seen it dozens of times, regular stainless braided AN hose should not be used for power-steering hose applications. Pressure spikes in the power-steering system can exceed the burst strength of regular AN hose. That is why companies like Aeroquip and Earl's have developed specific power-steering hose, complete with its own unique steel fittings, for use in these systems. Power-steering hose is usually made of an elastomer tube, polyester inner braid with wire-braid reinforcement, and a polyester-braid cover. Its maximum operating pressure is rated at 2,250 psi. While ideally suited for steering and hydraulic systems, this type of hose can be used in other applications including fuel, oil, and compressed air. Most Winston Cup pit crews use this type of hose with their "over-the-wall" air tools because of its flexibility and extreme pressure-spike capabilities in case it gets run over.

Braided hoses can dress up any engine compartment and can certainly add to the life expectancy of your car. When planning to upgrade your hoses, keep in mind the total costs involved and determine if the benefits of changing every hose is worth the expense. Of course, there will always be those who want the look of braided hose without the high cost, and for them there are braided hose coverings available which slip over the factory hoses to dress up their appearance. If you do decide to go stainless, you'll match looks and performance with those who've walked on the moon and shook hands in the winner's circle. CHP