Using our specialist hose-burst pressure rig, we tested the XDB range of hoses against both black rubber hoses (various constructions) and standard 3-ply silicone hoses. How Samco XDB Technology works.
Step 1 – Multi-ply Silicone Hose
At the heart SamcoXDB hoses is our world-renowned multi-ply silicone core which is hand-made using multiple layers of silicone rubber reinforced with specialist fabrics. We use only the finest quality Automotive grade European Silicone, and depending on the application, we use either 3 or 4 plies, using Nomex fabrics where necessary, to withstand temperatures up to 250oC .
In addition, specially formulated “flouro-silicone” is used for lining out Turbo hoses to provide optimum resistance to oil vapour. The resulting hoses offer a lifetime of reliable performance, guaranteed not to perish or crack like standard black rubber hoses.
Step 2 - Extra Nomex high temperature ply.
With our Xtreme Duty Build (XDB™) technology, we then add an extra 4th or 5th Nomex® high temperature ply. This gives maximum protection from radiant heat sources (up to 250oC) under the bonnet, protecting the core hose from heat ageing effects - vital when engine ventilation is reduced such as when the vehicle is used in low speed off-road work.
This extra ply also increases the hose's burst pressure by up to 100%*compared to standard black rubber hose, and by over 30%* compared to an equivalent silicone hose without this final layer. Importantly this extra Nomex ply offers this extra burst resistance specifically in the weakest areas of a hose – at mid-span.
Step 3 – Tuff-Cuff hose ends for maximum clamping force.
With XDB™, the final Nomex® ply is intentionally removed for an 18mm section at each end of the hose. By removing this material from under the clip, the 'setting' effects are dramatically reduced, and maximum clamp pressure transmission is achieved – up to 40%* improvement compared to black rubber hose. (Removing this section does not weaken the hose in any way - even after this section is removed, this area is still stronger than the mid-section because it is protected from radial expansion due to the proximity of the hose clip.)
The final feature of XDB™ is the prominent 'end shoulder'. As hoses take on pressure, they will try to bulge at the middle and straighten – this can lead to substantial pull-forces being exerted on the hose clamp area, as the hose tries to “blow off”. As the hose takes on pressure, it will try to slide off the pipe work, but the hose clamp will then have to slide over the pipebead for the hose to slide off further . If the clamp torque is correct and there is little material under the clamp, the then clamp cannot pass over the pipe-bead, instead the hose itself will try to 'sub-marining' underneath the clip – resulting in a hose “Blow-off” The SamcXDB square shoulder means that there is a substantial block of material behind the clip, which would need to be pulled under the clip this shoulder therefore increases the pressure rating at which any such blow-off would occur.