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Frequently Asked Questions

What are the differences between Polyester, Fiberglass and Aramid fabrics?

Polyester fabric is a tightly woven fabric with excellent resistance to water/coolant with moderate heat resistance when compared to other reinforcing fabrics. Polyester reinforced hoses are typically used on intercooler pipes, intakes, TB connections and even custom cooling system applications. The temperature limitations of polyester reinforced hoses ranges from -65°F to +350°F. This prohibits the use of polyester reinforced hoses near hot exhaust components as well as being directly mounted to the turbo.

Fiberglass is a trademarked product of the Owens Corning company, invented in 1938 and marketed as a home insulation product (Fiberglass). While home insulation remains one of the most common applications of fiberglass, the name itself has become a generic term for any material containing thin fibers of glass formed into a woven layer or used as reinforcement. Fiberglass cloth has excellent heat resistance at relatively low cost. Fiberglass cloth retains approximately 50% of room temperature tensile strength at 700°F (371°C); approximately 25% at 900°F (482°C); with a softening point of 1555°F (846°C) and a melting point of 2075° F (1121 °C).  It also exhibits good chemical resistance and thermal conductivity. Unfortunately, its lack of low temperature and flex resistance, as well as its overall brittleness makes it a poor choice for modern automotive hose applications.

Aramid fabric is the same material used in fire resistant apparel as it will neither burn nor melt and is quite flexible. It is the engineer’s choice for high temperature hoses and will allow you to mount these units directly coming off of the turbo. This can only be done safely with either a Aramid or fiberglass reinforced hose. The maximum sustained temperature for an Aramid reinforced hose is 500°F. If you are installing a turbo system that needs a straight coupler off of the turbo, you would need to look at our selection of Aramid reinforced couplers.

What size of hose/couplers should I use on my vehicle?

Where metal is always measured on the OD (Outside Diameter) of the tube, hose is always measured on the ID (Inside Diameter) of the hose. Therefore when choosing your couplers, hose or transitions, please keep in mind that you want the same ID hose as the OD of the pipe. For example, 2.50" intercooler pipes require 2.50" intercooler couplers, or a reducer going from 2.50" to your desired size. It is not necessary to order larger size couplers than your tubes. In fact this can lead to a loss in boost pressure or misleading MAF readings.

Does the amount of reinforcing layers really matter?

We manufacture our wrapped hose to the SAE J20 R1 specification. If the Society of Automotive Engineers (SAE) didn't think it mattered, then we would not have written a specification for us to follow. These engineers have determined what normal operating pressures and burst pressure should be for each size of hose. Furthermore the specification calls out the number of plies and the hose wall thickness required to be approved. Within the specification there are requirements for 3 and 4 ply hose. Nowhere in the specification does it say that a 1 or 2 ply hose is acceptable.  In fact, for our commercial customers inMexicoandSouth Americawhere road conditions can be poor and excessive engine vibration from older vehicles is an issue, it is not uncommon for us to build 5 or even 6 ply hoses to withstand these extreme conditions.

Is a thicker walled hose stronger than a thinner walled one?

Not necessarily.  The strength of a hose is provided almost totally by the fabric re-enforcement, not by the rubber.  We have built 4 ply aramid CAC Hoses with a wall as thin as .075" that had the exact same burst strength as ones with a wall of .175".  Thin walled hoses can, however, be subject to vacuum collapse as a result.

I have heard that 4 ply hose is hard to cut, is this true?

4 ply reinforced hoses are no different to cut than 2 or 3 ply hoses. Silicone, by nature has very poor cut growth resistance. We use reinforcing layers to help produce a stronger hose. If you are purchasing long lengths of hose and need to cut them down to length upon installation, you will need the following: A Liner clamp properly sized for the hose you intend to cut, tape measure, and a fresh razor blade utility knife (we suggest that you find the type of knife that utilizes the trapezoidal blades that are double sided).

Follow these simple steps for a safe, clean and straight cut. Align the clamp on the hose about where you think. Place the tape measure on one end of the hose and get your clamp straight perpendicular to the centerline of the hose. Make sure that the clamp band is the same distance from the end of the hose by using your tape measure and then tighten the clamp on the hose. Insert the point of the blade through the outer wall of the hose using the clamp as a guide. Once you have penetrated through the wall of the hose, slide the blade along the edge of the clamp until you have reached the back side of the clamping block. Unscrew the clamp and finish the cut free-hand for about 1/2 inch.

Aren’t all silicone materials essentially the same?

Definitely not!  Rubber compounding is very much like baking.  The compounder or chemist writes a recipe containing a number of different ingredients that are used to impart specific properties.  Imagine that you have a cookbook with 50 different recipes for chocolate cake. Although they all maybe chocolate cake, there can be a huge variety that all look and taste quite different.  The same thing holds true for rubber.  You can have 50 different recipes for, lets say, 70 Shore Silicone and they can all be quite different in properties.  The secret to success is to have the right baker, with the correct recipe, the proper equipment and the experience to use them all correctly.

I have heard that using different colors on the inside of the hose and the outside of the hose is a sign of a poor constructed hose, is this true?

This is actually a myth. The inside of the hose is called the liner and the outside of the hose is called the cover or jacket. Some manufactures utilize a 2 part manufacturing process where the liner is first extruded through a die to the correct size and partially cured to hold its shape during the final steps. The liner is then slid over a mandrel and the individual layers are then hand wrapped on top of the liner.

Since silicone is one of the easiest polymers to color, some manufactures started using different colors to be able to visually differentiate their products from other manufactures. One company may utilize a flame red liner where as another company may utilize an iron oxide red liner which is closer to red. The 2 different colors used in making silicone hose are more of a fashion statement more so than a functional one.

We utilize the one color design in our high performance hoses for the looks and ease of purchasing raw materials. The liner is manufactured using the same raw silicone as the cover and reinforcing layers therefore we only have to purchase 1 color in bulk rather than 2.  Many of our commercial and industrial hoses, on the other hand, are built using the two color construction method because that’s what those customers prefer.

I have heard of other companies making 1000ºF resistant silicone hose, do you offer these too?

If anybody tells you they have a 1000ºF resistant silicone hose then they probably have a bridge or two to offer you as well. All reputable silicone manufacturing companies will give you the same information; there is NO SILICONE COMPOUND THAT CAN WITHSTAND 1000ºF for any significant length of time. We have made special silicone compounds that have stood up to 2000°F+ environments, but for only the brief seconds or fractions of seconds required by the specifications.  We don’t go around claiming that we have a 2000°F resistant silicone.  Why do they?

Is it true that brick red silicone will withstand higher temperatures than other colors?

Yes and No.  While it is true that red iron oxide (the pigment used to make most brick red silicones red) does improve the thermal properties of silicone, much higher loading levels are required than those normally used for simply coloring the material.  All of our hose formulas, regardless of color, include special additives to increase the high temperature resistance of our products.

Does a longer transition/reducer have a higher flow rating?

The length of the hose does not control the flow characteristics. We too have read about several companies stating that their 4 inch or 5 inch long reducers flow better than a 3 inch long reducer. In order to prove this we need to know the anatomy of a reducer. The flat section on the reducer where the clamps are positioned is called the cuff. If we made each cuff 5 inch long and made the reducers over all length 12 inch would this flow better? NO, turbulence can be caused by the angle at which the transition from one size to the other is made

Can your silicone vacuum hose be used in a fuel/oil environment?

Silicone has very poor resistance to fuel and oils. Silicone hoses should never be used as oil drain lines or fuel lines. Over time the silicone will swell and the physical properties will diminish to the point where the hose will fail. On certain vehicles like the Mazda RX7 there are a lot of aromatic hydrocarbons flowing through the vacuum lines. We have seen evidence of oil contamination in these lines where the silicone has actually swelled to the point where the hoses crumble.

If you need an oil resistant material, you should be using a Viton® or other brand of fluoroelastomer vacuum hoses, or a silicone hose with a Fluorosilicone liner.

What is the difference between the silicone vacuum hose at the corner auto parts store and your platinum catalyzed silicone?

Manufactured in the U.S.A.from a proprietary formulation that has been rigorously tested in our on-site Laboatory, Alliance Floline Vacuum Hoses are far superior to most other Vaccum Hose currently available for two very important reasons:

Not all 70 Shore Silicones are created equal.  In it's unfinished state silicone looks and feels like Silly Putty.  In fact, that's exactly what Silly Putty is; uncured silicone rubber.  Since it first became commercially available in the 1940’s, silicone rubber has typically used organic peroxide catalysts as the "curing agent" to achieve vulcanization.  More recent innovations in organic chemistry have resulted in the development of silicone rubbers that can be cured by the use of platinum compounds.  While they are more expensive than their conventional peroxide cured counterparts, platinum cured silicone formulations typically exhibit significantly  improved physical properties such as tensile and elongation as well as higher tear strength and abrasion resistance.   An added benfit to you is that our Platinum Cured hoses will be snappier and much more kink resistant than conventional hoses.

Vaccum Hoses are sized by the Inside Diameter (I.D.), but most manufacturers don't publish the wall thickness of their hose. Since a thicker wall means more material and therefore higher costs, most manufacturers keep their wall construction to the barest minimum. As a result, there is a huge variation in wall thicknesses from one manufacturer to another with absolutely no "standard" wall.  Our Heavy Duty construction ensures that your hose won't collapse under even the most extreme vacuum pressure.

Why can’t I just use regular worm gear clamps on my hoses?

Silicone compounds inherently have very poor cut growth resistance. The use of a regular worm gear clamp may damage the hose during installation. When tightening down your clamps on the hose, the silicone can actually "extrude" through the slots, shearing the hose. This extrusion of the silicone cover can cause hose failure and immediate loss of boost. Liner clamps have been specifically designed for silicone hose. There is a protective 1 piece stainless liner that is placed on the inside of these types of clamps preventing the silicone from touching the gear. You do not need to use liner clamps on any other rubber hoses because most organic rubber compounds have much better cut growth resistance than silicone.

I’ve heard that some manufacturers offer Fluorocarbon (Viton®) lined hoses, why don’t you?

We have done extensive research into FKM lined hoses and, at present, the technology does not exist to adequately ensure the long term high temperature adhesion values demanded by the service conditions of these hoses. We have seen too many of our OEM customers replacing relatively new engines under warranty because the FKM hose liner peeled away and got sucked into a turbocharger. We are continuing our research and, will begin to offer this type of hose construction if, and when, we feel this problem has been eliminated. Until then, we suggest you talk to us about a Fluorosilicone lined hose instead. That technology works now.