In a couple of past segments right here on RacingJunk, we dug into the whys and hows of AN fittings. It’s a pretty easy (and logical) system once you get the hang of it. After the various styles of adapters and hose ends in your system are selected, you have to figure out which type of hose to use. And you’d better believe there are differences in hose. There are lots of different hose configurations out there. For the purposes of this plumbing series, we’ll look at two of the very best choices out there for hot rods or race cars: Earl’s traditional Perform-O-Flex hose and Earl’s latest Ultrapro hose.
The most common performance hose you’ll run into is one with some form of rubber liner wrapped with a stainless steel braid. I typically use a lot of Earl’s Perform-O-Flex hose since it’s easy to obtain and very high in quality. Perform-O-Flex hose in this range is based around a special synthetic material for the elastomer (inner hose). In essence, this inner hose is a synthetic rubber tube that has a “clean” inside diameter and flows very well.
A partial-coverage protective sheath of stainless steel braid is embedded in the Perform-O-Flex liner during manufacturing. The reinforced hose liner is then bonded to a full-coverage outer protective sheath of high tensile stainless steel wire braid. This is likely the toughest hose you can find. Earl’s points out that Perform-O-Flex, with its inner liner, remains flexible at temperatures between -40 and +300 degrees F.
Perform-O-Flex hose is intended for use with Swivel-Seal, Auto-Fit and Auto-Mate hose ends only. No other Earl’s hose ends are intended for use with Perform-O-Flex hose. The use of other manufacturer’s hose ends is not recommended.
Earl’s Perform-O-Flex racing hose is engineered to operate continuously in a temperatures range of -40° F to over +300° F. Aside from the wide heat range, this hose is capable of withstanding considerable pressure (it has a maximum operating pressure of 1500 PSI) and vacuum. By design, it is unaffected by most fuels, oil and coolant. As a result, it can be used for almost all automotive fluid transfer applications except brake lines and air conditioning hose. That means it can be successfully used in conjunction with race gas, pump gas, methanol/alcohol, E85, diesel, engine coolant, oil and automatic transmission fluid.
Over the years there’s been a trend to move toward lighter hose in racecars. At the same time, today’s high performance vehicles require a plumbing system designed to withstand today’s modern ﬂuids, harsh environments, brutal vibration, ﬂow requirements and extreme pressures. Even the best synthetic hose in the world can eventually become compromised by the petroleum blend we now call gasoline (the chemical mix in certain fuels is responsible for this and the mix is ever-changing). The Engineers at Earl’s Performance recognized this and set to work on a lightweight hose that wouldn’t be affected by harsh chemicals. What they came up with is the Ultrapro hose line.
Ultrapro features a PTFE inner liner that is impervious to all known fuels, oils and coolants used in automotive applications (race and street). It was designed from the beginning to withstand harsh environments, brutal vibrations, high flow requirements and extreme pressures. Where regular PTFE (Teflon) hose is very stiff and has difficulty making tight bends, the double-helix ribbed inner hose liner used in Ultrapro offers extreme ﬂexibility and full ﬂow, making difficult plumbing jobs a snap. The liner is reinforced with an outside glass-ﬁber wrap for additional strength and integrity. Meanwhile, the PTFE inner liner is carbon infused for static dissipation. There’s more too: Earl’s looked at flow through various convoluted hoses and they learned that the actual shape can have an effect upon laminar flow. That resulted in a redesign of the liner. The proprietary shape of the PTFE liner used in Ultrapro ends up with ultra-low coefﬁcient of friction to promote maximum fluid ﬂow through the hose.
Ultrapro hose is compatible with all automotive applications except for brake and air conditioning lines. Polyester braid Ultrapro hose has a maximum rated pressure of 250 PSI and a maximum rated vacuum of 28-inches HG. Meanwhile, stainless braid Ultrapro hose has a maximum rated pressure of 500 PSI and a maximum rated vacuum of 28-inches HG.
Ultrapro is assembled with an olive that threads onto the double helix ribbed inner liner of the hose for positive engagement and retention of the hose-ends. It can be assembled by way of crimp on hose ends or twist on hose ends (we’ll dig into these later). It’s currently available with a black polyester braid that proves up to 67% lighter than traditional rubber hose with stainless steel braid. It’s also available with a stainless steel braid that is up to 37% lighter than traditional rubber hose with stainless steel braid. Available diameters include -6, -8, -10,
-12, -16, and -20 sizes in both woven polyester braid and stainless steel braid.