Dont want to sound patronising mate but did it have an aftermarket Bov?
If its standard it wont make a sound as it recircs back into inlet.
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If its an aftermarket one, they can be adjusted by a nut on them which decides what psi they vent at.
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If its a Rev1/2 Id keep it standard as venting to atmosphere will make the car run rich and will be
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'jerky'