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Blow off valves and dump valves.
When the throttle is closed (when you lift off the accelerator) in a turbo driven engine there is a build up of pressure as forced air is still coming from the turbo. Lifting off the throttle is a lot like putting a plug in the sink – the flow through is stopped and water would just build up and overflow the sink.
So what exactly is engine knock and how dangerous is it? What causes engine knock and how can it be avoided?
You may notice a knocking or rattling noise from your engine or a sudden loss of power under full throttle.
Immediately back off the throttle and only use low rpm engine speeds until you can get the engine investigated.
The chances are that you are suffering from a condition known as “engine knock”.
Principles of porting an engine and big valve conversions
The inlet and outlet ports on the engine block are usually larger than those of the manifolds that connect to them.
This allows for scope in the manufacturing process to allow for mismatched alignment.
Generally the engine ports are larger in the upstream flow direction avoiding turbulance but power gains can be made by matching these up.
Cryogenic engine treatments
When putting more power through an engine you need to ensure that every part will perform at its optimum.
One of the motorsports favourite techniques to improve the durability of an engine is a process know as cryogenic treatments.
As you can guess from the use of the word Cryo – it involves the cooling and heating of the engine block to temper the metal changing its structure.
