There are four important things about silicone hose which have a direct effect on clamp selection: silicone hose is soft, hard to seal, expensive, and durable. Based on the size of silicone, inclusion or absence of reinforcement fiber, object the silicone is being connected to, and purpose of the system, we use two types of clamps when connecting silicone coupler and hoses to the associated components that they interconnect with: T-Bolt Band Clamps and Worm Drive, Concentric Lined Band Clamps. These two options allow us to get all of the benefits of silicone's durability and heat resistance, without compromising its use by damaging it or causing it to seal poorly.
Description of each style of clamp:
T-Bolt Band Clamps feature an inner band that is latched and pulled tight using a standard style bolt, with a T 'head' at one end retained by a loop in the clamp and a trunnion and nut in a loop on the opposing side of the clamp. These systems,while a bit more bulky than conventional hose clamps, provide superior clamping force, a wide 3/4″ band for spreading the additional clamping loads, and feature stainless construction of the band and trunnion with a plated carbon steel screw and lock nut. Before you ask, there is a reason why we choose the style with the carbon screw. In threaded fastener applications, carbon steel provides a strong connection without risking the galling that often happens when stainless fasteners are put into high load situations (especially when using lock nuts). All of our T-Bolt Band Clamps meet or exceed SAE Spec. J1508
Concentric Liner Band Clamps may look and feel like your typical worm drive hose clamp, but on further investigation, you'll see they have a lot of features that make them lightyears beyond the functionality of a typical hose gnawing worm drive clamp. To protect the hose or coupler from extrusion and shear, an inner liner is used to cover the slots in the worm gear on the outside layer of the clamp. Unlike other manufacturers liner clamps, these liners are an integral extension of the hose clamp band, providing a perfectly concentric and smooth surface around the full diameter of the silicone hose. Likewise, the design of the worm drive thimble is recessed completely flush to the inside diameter of the clamp, so as to avoid damaging the hose surface when clamping. There are no protrusions inside these clamps at all, and unlike many 'silicone safe' marketed designs, there is no coating on any of the parts that can wear off over time and use. They feature full stainless construction, which is absolutely necessary on silicone hoses – as the hose will easily outlive any corrosion prone steel in an engine compartment. Our Liner Clamps also come in 1/2″ band width for a wide compression area around the surface of the hose. Beyond that, the worm gear drive system on our clamps features a four piece design rather than the conventional three piece design. This provides low idle torque requirements for when you're tightening or opening a loose clamp and high torque capabilities once the clamp begins to snug down. Because of the four piece design of the clamp and thimble mechanism, they are also highly resistant to spreading and destruction under high torque. All of our Concentric Liner Band Clamps meet or exceed SAE Spec. J1508
Application and decision making criteria:
T-Bolt Band Clamps are great for high torque applications where silicone hoses need to be held tight in place and retain high boost pressures, or in applications where the clamping mechanism acts as a primary structural connection between on end of a system and the fixed component to which it attaches.
Concentric Lined Band Clamps are excellent for attaching hoses that are used for pressurized systems in smaller diameter such as silicone coolant hoses and cooling system applications as well as lower pressure, larger diameter applications such as intake tubing connections. We also use them exclusively in applications where non reinforced silicone hose is used (boost solenoid lines, ancillary coolant lines, ancillary vacuum and flourosilicone oil catch can lines, etc). We also use these in applications where a good concentric seal is required but the object being sealed to is at risk of damage when high torque is applied (infernal plastic fantastic VW coolant manifolds and thermostat housings, connections to factory blow molded and rotomolded airboxes, connections to rotomolded plastic intake tubes, etc)
If you're interested in hearing more about the clamping solutions we use for silicone hoses, or have an alternative that you have had success with in the field, let us know by dropping us an email. Perhaps there is another component we use that you'd like to understand more about. We're here for you and enjoy discussing the reasons why we choose the components we include with each of our kits. We put a lot of time and thought into our designs and always like to discuss alternatives and details.
Jason Griffith, Engineering Director. Nameless Performance, Inc.