Exhaust Bellow's Explained
What is an Exhaust Bellow?
Exhaust Bellows are constructed with a inner slip joint and then the exterior has a series of rib sections, these ribs allow for movement while completely sealing the inner slip joint from leaking.
Most commonly exhaust bellows are constructed from 304 stainless steel but these also can be found in 321 stainless steel for extreme high heat applications
What does an Exhaust Bellow do?
A Bellow gives movement to your wastegate or exhaust pipes, these are also commonly used for turbo manifold cross-over pipes aswell.
When fabricating this type of component the alignment can be tricky at the best of times especially when using stainless steel, this material is renowned for alot of movement when welding. A Bellow will aid in the alignment when assembling these components.
This movement also happens under general everyday use aswell, when pipes heat up they expand and this is one of the main reasons to use an exhaust bellow, to enable the pipes to move and expand without stressing other areas of your pipe work.
Exhaust Bellow vs Exhaust Flexi Joint
These two options visually are very different but there purpose is quite the same. A exhaust bellow or exhaust flexi joins (what is an Exhaust Flexi) main job is to give movement to the tubes they are attached to. Without the use of these you will have a much greater chance of your pipes cracking from either thermal expansion or general movement and vibration.
Pros & Cons
- The overall length are shorter so this is an advantage in tight spaces
- Bellows have a solid inner liner so are more suited for turbo manifold applications and high heat
- Because of the way the bellows are manufactured the inner slip join steps down so they can be around 2-3mm smaller than the inside diameter of the tube size. This can cause flow restrictions in some cases when alot of volume is passing through
- Stainless steel is more prone to cracking so over long periods of time the outer ribs work harden and can lead to cracking issues
- Because of there construction and the material they are made from the exhaust flexi will provide a long term ability of movement without cracking.
- These are longer than exhaust bellows so are not ideal for tight spaces
- Because of the thin interlocking inner liner the exhaust flexi are not recommended for high heat applications